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COMPREHENSIVE 5-MARKER ANSWERS (K. Park Reference)

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1. TYPES OF COHORT STUDIES

1. Prospective (Concurrent) Cohort Study
   • Cohort is identified in the present and followed into the future
   • Exposure is recorded before disease occurs
   • Example: Doll and Hill's study on smoking and lung cancer
   • Advantage: Accurate exposure data; can study multiple outcomes
2. Retrospective (Historical/Non-concurrent) Cohort Study
   • Cohort is identified from past records; outcome has already occurred
   • Uses existing records (factory registers, hospital records)
   • Cheaper and quicker than prospective
   • Disadvantage: Dependent on quality of past records
3. Ambidirectional Cohort Study
   • Combines both prospective and retrospective components
   • Some outcomes already occurred; rest are followed prospectively
4. Open (Dynamic) Cohort
   • Members can enter or leave at different times
   • Membership changes over time
5. Closed (Fixed) Cohort
   • All members enter at the same time; no new entries
   • Followed until end of study period

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2. BARRIERS OF COMMUNICATION

1. Physical Barriers - Noise, distance, poor lighting, defective equipment
2. Semantic/Language Barriers - Use of technical jargon, different languages, unclear meaning, misinterpretation of words
3. Psychological Barriers
   • Fear, anxiety, mistrust of health personnel
   • Preconceived notions, selective perception
   • Emotional stress of patient/receiver
4. Cultural Barriers - Beliefs, taboos, customs, caste differences, traditional practices conflicting with health messages
5. Social Barriers - Illiteracy, poverty, social inequality, gender discrimination
6. Administrative/Organizational Barriers - Red tape, lack of feedback mechanism, poor planning of message
7. Perceptual Barriers - People hear what they want to hear; filter messages based on personal values
8. Physical Disabilities - Deafness, blindness, speech defects

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3. SICKNESS ABSENTEEISM

• Frequency Rate = (Number of spells of absence / Average number of workers) × 100
• Duration Rate = (Total days lost / Number of spells) - average duration per spell
• Spell Incidence Rate = Number of new spells per 100 workers per year
• Severity Rate = Days lost per worker per year

• Occupational diseases and injuries
• Non-occupational illness
• Malingering and personal reasons
• Domestic reasons

• Indicator of workers' health status
• Measures effectiveness of occupational health services
• Spells > 3 days are generally recorded
• Monday absenteeism - often not due to genuine illness

• Proper medical care and treatment
• Improvement of working conditions
• Health education
• Employee assistance programs
• Rehabilitation services

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4. MEDICAL MEASURES IN PREVENTION OF OCCUPATIONAL DISEASE

• Assess fitness for specific job
• Identify pre-existing conditions
• Establish baseline health record
• Exclude susceptible individuals from hazardous work

• Regular health check-ups during employment
• Early detection of occupational diseases
• Biological monitoring (blood lead, urinary metabolites)
• Lung function tests for dust-exposed workers

• Monitoring of workers exposed to specific hazards
• Audiometry for noise exposure
• Chest X-rays for pneumoconiosis
• Blood tests for chemical exposures

• Prompt treatment of occupational diseases
• Removal from exposure when disease detected
• Vocational rehabilitation and retraining

• Measurement of toxic substances in body fluids
• Blood lead levels, urinary benzene metabolites

• Educating workers about hazards
• Proper use of protective equipment
• Personal hygiene measures

• Adequate first aid at workplace
• Emergency treatment protocols

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5. ROLE OF FAMILY IN HEALTH AND DISEASE

1. Socialization - Teaches health habits, hygiene, dietary practices from childhood
2. Economic support - Provides financial resources for health care
3. Emotional support - Mental health and psychological well-being
4. Health decisions - Family decides when and where to seek care

1. Genetic transmission - Hereditary diseases (diabetes, hypertension, hemophilia)
2. Infection spread - Communicable diseases spread within family
3. Nutritional habits - Family dietary practices affect nutritional status
4. Behavioral factors - Smoking, alcohol, lifestyle habits learned in family

1. Primary caregivers during illness
2. Compliance with treatment depends on family support
3. Rehabilitation and recovery supported by family

• Family physician concept
• Family health records
• Comprehensive care for all members

• Nuclear family vs joint family
• Single-parent families and health risks
• Broken homes and mental health of children

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6. FOOD FORTIFICATION

• Correct nutritional deficiencies in the population
• Cost-effective public health intervention
• Does not require change in food habits

• Deficiency must be widely prevalent
• Food must be widely consumed
• Addition must not alter taste/appearance
• Must be stable during storage/cooking
• Must be technically feasible and affordable

• Universal Salt Iodization in India
• Double Fortified Salt (DFS) with iron + iodine
• FSSAI mandated fortification standards

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7. FOOD ADULTERATION

1. Intentional Adulterants - Deliberately added; e.g., water in milk, chalk in flour
2. Incidental Adulterants - Due to negligence; e.g., pesticide residues, rodent droppings
3. Metallic Adulterants - Arsenic from pesticides, lead from containers

• Epidemic dropsy (argemone oil)
• Lead poisoning (lead chromate)
• Liver damage (aflatoxins)
• Gastrointestinal illness

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8. OXIDATION BOND (Note on Chemical Bonds in Biology)

• Process where ATP is synthesized using energy from electron transport chain
• High-energy phosphate bonds (~P) store energy
• Occurs in mitochondria

• Phosphate bonds in ATP are high-energy bonds (~)
• Energy released on hydrolysis: ~7.3 kcal/mol
• Important in energy metabolism of macronutrients

• Carbohydrates, fats, proteins undergo oxidation to produce energy
• Measured in calories
• Caloric value: Carbohydrates = 4 kcal/g, Proteins = 4 kcal/g, Fats = 9 kcal/g

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9. HUMAN DEVELOPMENT INDEX (HDI)

1. Health - Measured by Life Expectancy at Birth
2. Education - Measured by Mean Years of Schooling + Expected Years of Schooling
3. Standard of Living - Measured by GNI per capita (PPP$)

• Very High Human Development: HDI ≥ 0.800
• High: 0.700-0.799
• Medium: 0.550-0.699
• Low: < 0.550

• Better measure of development than per capita income alone
• Focuses on human capabilities
• Allows comparison between countries
• Guides policy formulation

• India is in medium human development category
• HDI approximately 0.633 (recent years)
• Ranked around 132 out of 191 countries (2021-22)

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10. GENETIC COUNSELLING

1. Provide accurate diagnosis
2. Estimate recurrence risk
3. Explain options to family
4. Support decision making
5. Ensure psychological adjustment

• Advanced maternal age (>35 years) - Down syndrome risk
• Previous child with chromosomal abnormality
• Family history of genetic disorder
• Consanguineous marriage
• Repeated abortions (>3)
• Exposure to teratogens
• Abnormal prenatal screening results

1. Accurate diagnosis (clinical + laboratory)
2. Establish pedigree (family tree)
3. Calculate recurrence risk
4. Communicate risk clearly
5. Discuss options (prenatal diagnosis, adoption, etc.)
6. Follow-up and support

• Autosomal dominant: 50% each child
• Autosomal recessive: 25% if both parents carriers
• X-linked recessive: 50% of sons affected

• Amniocentesis, chorionic villus sampling
• Ultrasound, fetoscopy
• Maternal serum screening (triple/quadruple test)

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11. SIGNS OF POOR MENTAL HEALTH / WARNING SIGNS

1. Cognitive Signs:
   • Confused thinking, difficulty concentrating
   • Memory problems
   • Inability to make decisions
2. Emotional Signs:
   • Prolonged sadness, depression, hopelessness
   • Excessive fears, worries, anxieties
   • Extreme mood swings
   • Emotional blunting or apathy
3. Behavioral Signs:
   • Social withdrawal and isolation
   • Changes in eating/sleeping habits
   • Loss of interest in activities
   • Neglect of personal hygiene
   • Substance abuse (alcohol, drugs)
   • Self-harm or suicidal thoughts
4. Physical Signs:
   • Unexplained physical complaints (headaches, stomach aches)
   • Fatigue without cause
   • Changes in libido
5. Social Signs:
   • Problems at work/school
   • Inability to fulfill responsibilities
   • Relationship difficulties
   • Aggressive behavior

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12. LEVELS OF PREVENTION

• Aim: Prevent occurrence of disease
• Health Promotion: Health education, nutrition, housing improvement, recreational facilities
• Specific Protection: Immunization, chemoprophylaxis, use of protective equipment, safe water supply

• Aim: Early detection and prompt treatment
• Early Diagnosis and Treatment: Screening programs, case finding, prompt treatment to halt disease progression
• Goal: Shorten duration, prevent complications, reduce infectivity

• Aim: Limit disability and restore function
• Disability Limitation: Adequate treatment to prevent complications
• Rehabilitation:
  • Medical rehabilitation
  • Vocational rehabilitation
  • Social rehabilitation
  • Psychological rehabilitation

• Prevention of emergence of risk factors
• Changes in social/environmental conditions
• Example: Prevention of obesity, tobacco use before they become prevalent

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13. MASS APPROACH IN HEALTH COMMUNICATION

1. Television - Widest reach, audio-visual impact
2. Radio - Reaches rural and illiterate populations
3. Newspapers/Print Media - Educated population
4. Posters and Hoardings - Visual messages in public places
5. Films and Documentaries - Entertainment-education
6. Internet/Social Media - Modern mass communication

• Reaches large numbers simultaneously
• Cost-effective per capita
• Can create social norms
• Suitable for non-stigmatizing messages

• Not targeted; wasteful resources on non-susceptible
• Cannot address individual risk factors
• Low impact - small shift in population behavior
• No immediate feedback
• May cause anxiety in low-risk individuals

• Pulse Polio campaign
• AIDS awareness campaigns (Red Ribbon campaign)
• Family planning media campaigns

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14. COMMUNITY NUTRITION PROGRAMS IN INDIA

1. ICDS (Integrated Child Development Services) - 1975:
   • Target: Children 0-6 years + pregnant/lactating women
   • Services: Supplementary nutrition, immunization, health check-up, nutrition education
   • Delivered through Anganwadi centers
2. Mid-Day Meal Program (MDM) - 1995 (national):
   • Free cooked meals to school children (Class 1-8)
   • Improves enrollment, retention, nutrition
3. National Nutritional Anemia Prophylaxis Program:
   • Iron and folic acid tablets for children and pregnant women
   • Weekly Iron and Folic Acid Supplementation (WIFS) for adolescents
4. National Iodine Deficiency Disorders Control Program:
   • Universal salt iodization
   • Monitoring iodine levels in population
5. Vitamin A Supplementation Program:
   • Biannual vitamin A doses to children 9 months - 5 years
6. Special Nutrition Program (SNP):
   • For children under 3 years, nursing mothers in tribal/backward areas
7. Kishori Shakti Yojana:
   • Nutrition for adolescent girls
8. POSHAN Abhiyaan (National Nutrition Mission) - 2018:
   • Reduce stunting, undernutrition, anemia in children and women

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15. THE ESI ACT (Employees' State Insurance Act, 1948)

• Enacted in 1948, implemented from 1952
• Social security legislation for Indian workers
• Administered by ESIC (Employees' State Insurance Corporation)

• Factories employing ≥10 workers (with power) or ≥20 (without power)
• Wages up to ₹21,000/month (₹25,000 for persons with disability)
• Extended to shops, hotels, restaurants, cinemas, etc.

• Employee: 0.75% of wages (reduced from 1.75% in 2019)
• Employer: 3.25% of wages (reduced from 4.75%)
• State government: 1/8th of medical benefit cost

1. Medical Benefit - Full medical care from day of entry
2. Sickness Benefit - 70% of wages for 91 days/year
3. Extended Sickness Benefit - For 34 long-term diseases (2 years)
4. Maternity Benefit - 100% wages for 26 weeks
5. Disablement Benefit - Temporary/permanent disablement
6. Dependants' Benefit - Death due to employment injury
7. Funeral Expenses - Up to ₹15,000

• April 1 - Sept 30 → October 1 - March 31
• October 1 - March 31 → April 1 - September 30

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16. ICEBERG PHENOMENON

• Above water (visible): Diagnosed, clinically apparent cases presenting to health facilities
• Below water (invisible): Subclinical, undiagnosed, mild, or latent cases

1. Clinical disease - Tip of iceberg
2. Pre-symptomatic disease - Infection without symptoms yet
3. Subclinical disease - No symptoms at all
4. Latent infection - Dormant infection (e.g., TB, herpes)
5. Carrier state - Healthy carriers

• Hypertension: For every diagnosed case, many undiagnosed exist
• Diabetes: ~50% undiagnosed
• Polio: 200 subclinical infections per 1 paralytic case
• TB: Many infected but disease in few

• True disease burden underestimated if only clinical cases counted
• Screening programs needed to detect submerged portion
• Community surveys reveal true prevalence
• Control programs must target iceberg base

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17. ADVANTAGES OF CASE-CONTROL STUDY

1. Suitable for rare diseases - Can study diseases with low incidence without waiting years
2. Quick and inexpensive - Results available rapidly; lower cost than cohort studies
3. Small sample size required - Especially useful for rare outcomes
4. No follow-up needed - Retrospective design; no attrition problem
5. Ethical - No deliberate exposure of subjects to harmful agents
6. Multiple exposures studied - Can examine many risk factors for one disease simultaneously
7. No risk to subjects - Observational; no intervention
8. Good for diseases with long latent period - e.g., cancer, chronic diseases
9. Generates hypotheses for further prospective studies
10. Can use existing records - Hospital records, disease registries

• Cannot calculate incidence or relative risk (only OR)
• Recall bias, selection bias
• Cannot study multiple outcomes
• Temporal relationship sometimes unclear

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18. OPEN VIAL POLICY

1. Has not expired
2. Has been stored under proper cold chain conditions (2-8°C)
3. Has not been submerged in water
4. Vaccine Vial Monitor (VVM) has not crossed the discard point
5. No visible contamination, floating particles, or abnormal appearance

• OPV, DPT, TT, Hepatitis B, DT
• Multi-dose vials of these vaccines

• BCG - discard after 4 hours (no preservative, reconstituted)
• Measles - discard after 4 hours
• JE vaccine
• Any lyophilized vaccine that has been reconstituted

• Reduces vaccine wastage
• Improves cost-effectiveness of immunization programs
• Particularly important in outreach sessions

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19. SCREENING TEST vs. DIAGNOSTIC TEST

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20. NATIONAL MENTAL HEALTH PROGRAM (NMHP)

1. Prevention and treatment of mental and neurological disorders
2. Rehabilitation of the mentally ill
3. Prevention of and reduction in associated disability

1. Ensure availability and accessibility of minimum mental health care for all
2. Encourage application of mental health knowledge in general health care
3. Promote community participation in development of mental health services
4. Stimulate efforts toward self-help in communities

1. Integration of mental health with general health services - Training PHC staff
2. Decentralization of psychiatric services - To district level
3. Promotion of community mental health
4. Training of human resources

• Launched 1996 in pilot districts
• Provides outpatient services at district hospital
• Training for PHC doctors, nurses
• School mental health programs
• Integrated counseling centers

• Early detection and treatment
• Training of health personnel
• IEC activities
• Monitoring and evaluation

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21. DIETARY GOALS

1. Total fat: 15-30% of total energy (saturated fat <10%)
2. Protein: 10-15% of total energy
3. Carbohydrates: 55-75% of total energy (complex carbs preferred)
4. Free sugars: <10% of total energy (WHO recommends <5%)
5. Dietary fiber: >25 g/day
6. Salt (NaCl): <5 g/day
7. Fruits and vegetables: ≥400 g/day (5 portions)

• Increase consumption of fruits, vegetables, whole grains, legumes
• Decrease consumption of saturated fats, trans fats, refined sugars, salt
• Achieve energy balance to maintain healthy weight
• Limit alcohol consumption

• Rice/wheat as staple + pulses + vegetables + milk
• Reduce use of salt and sugar
• Increase green leafy vegetable intake
• Promote breastfeeding

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22. GLOBAL WARMING

• Carbon dioxide (CO2) - 60% contribution (fossil fuels, deforestation)
• Methane (CH4) - 20% (livestock, paddy fields, landfills)
• Nitrous oxide (N2O) - agricultural fertilizers
• CFCs, HFCs - industrial/refrigerants
• Water vapor

1. Direct effects: Heat stroke, heat exhaustion, increased cardiovascular mortality
2. Infectious diseases: Spread of vector-borne diseases (malaria, dengue - expanded range); waterborne diseases
3. Respiratory diseases: Increased air pollution, pollen, ozone
4. Food insecurity: Crop failures, malnutrition
5. Mental health: Displacement, disaster-related psychological trauma
6. Sea level rise: Flooding, displacement of coastal populations

• Reduce fossil fuel combustion
• Renewable energy adoption
• Reforestation
• Energy efficiency measures
• International treaties (Kyoto Protocol, Paris Agreement)
• Adaptation strategies in health sector

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23. PRINCIPLES OF HEALTH EDUCATION

1. Credibility: Educator must be credible; information from reliable sources; based on scientific facts
2. Interest: Topic must be relevant and interesting to the audience; based on felt needs
3. Participation: Active involvement of learners; two-way communication; self-discovery
4. Motivation: Messages should motivate people toward health action; focus on positive gains
5. Comprehension: Messages must be understood; simple language; avoid jargon; appropriate for literacy level
6. Reinforcement: Repeat messages; reinforce through multiple channels; positive reinforcement of good behavior
7. Feedback: Two-way process; educator must receive feedback; evaluate effectiveness
8. Relevance: Education must be relevant to local cultural context, beliefs, and practices
9. Learning by Doing: Practical demonstration more effective than lecture
10. Good Human Relations: Warmth, empathy, respect for learner's dignity
11. Setting Priorities: Focus on most important health problems of the community
12. Positive Approach: Emphasize positive health behaviors rather than just prohibitions
13. Evaluation: Regular assessment of knowledge, attitude, and practice (KAP) changes

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24. CIGARETTES AND OTHER TOBACCO PRODUCTS ACT (COTPA), 2003

1. Section 4: Prohibition of smoking in public places (offices, hospitals, restaurants, transport, educational institutions)
2. Section 5: Prohibition of all direct and indirect advertisement, promotion, and sponsorship of tobacco products
3. Section 6:
   • Prohibition of sale to/by minors (<18 years)
   • No sale within 100 meters of educational institutions
4. Section 7-9: Statutory warnings on tobacco product packages
   • 85% of pack surface must carry pictorial health warnings
   • Warnings: "Tobacco causes cancer," "Tobacco kills"
5. Section 10: Display of boards about prohibition of smoking at entrances of public places

• Violation of Section 4: Fine up to ₹200
• Violation of Section 5: Imprisonment up to 2 years and/or fine up to ₹1000
• Violation of Section 6: Fine up to ₹200

• India signed WHO Framework Convention on Tobacco Control (FCTC) 2004
• National Tobacco Control Program (NTCP) launched 2007
• National Quitline services available

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25. INDICATORS OF AIR POLLUTION

1. Suspended Particulate Matter (SPM):
   • PM10 (particles <10 μm) and PM2.5 (particles <2.5 μm)
   • Standard: PM10 <60 μg/m³ (annual mean, India)
   • PM2.5 most dangerous - reaches deep lung
2. Sulphur Dioxide (SO2):
   • Standard: 80 μg/m³ (annual mean)
   • Sources: Coal combustion, industries
3. Nitrogen Dioxide (NO2):
   • Standard: 80 μg/m³ (annual mean)
   • Sources: Vehicular exhaust, combustion
4. Carbon Monoxide (CO):
   • Standard: 10 mg/m³ (8-hour average)
   • Sources: Incomplete combustion, vehicles
5. Ozone (O3):
   • Photochemical pollutant
   • Ground-level ozone is harmful (vs. stratospheric ozone which is protective)
6. Lead (Pb):
   • Standard: 0.5 μg/m³ (annual mean)
   • Source: Leaded petrol (now banned in India)
7. Air Quality Index (AQI):
   • Composite index (0-500)
   • 0-50: Good; 51-100: Satisfactory; 101-200: Moderate; 201-300: Poor; 301-400: Very Poor; 401-500: Severe
8. Biological Indicators: Lichens disappear with SO2 pollution (bioindicators)

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26. PURIFICATION OF WATER AT HOUSEHOLD LEVEL

1. Boiling:
   • Most reliable method
   • Kill all pathogens if boiled for 1 minute (rolling boil)
   • Kills bacteria, viruses, cysts
   • Disadvantage: Cost of fuel; doesn't remove chemical pollutants; water may get re-contaminated
2. Chemical Disinfection:
   • Chlorination: Bleaching powder (chlorine 0.5-1 mg/L residual); Halazone tablets
   • Potassium Permanganate (KMnO4): Pink color indicates safe; used in rural areas
   • Iodine tablets: 2 tablets per liter
3. Filtration:
   • Candle filter (Pasteur Chamberland): Removes bacteria, turbidity
   • Sand filter (household type)
   • Ceramic filters
4. Solar Disinfection (SODIS):
   • Fill PET bottles with clear water
   • Expose to sunlight for 6 hours (or 2 days if cloudy)
   • UV radiation kills pathogens
5. Storage in Clean Vessels:
   • Use narrow-mouthed vessels
   • Avoid dipping hands/containers
   • Store off the floor
6. Modern Methods:
   • UV purifiers (kills bacteria, viruses)
   • RO (Reverse Osmosis) - removes dissolved solids, heavy metals
   • Combination UV+RO systems

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27. APPROACHES TO HEALTH EDUCATION

• One-to-one counseling (patient-doctor/nurse interaction)
• Most effective - tailored to individual needs
• Examples: Antenatal counseling, dietary advice, smoking cessation counseling

• Small groups (5-20 people) with common interest/problem
• Methods: Group discussion, lecture-discussion, role play, case study, demonstration, workshop
• Examples: Maternal education classes, diabetic education groups

• Reaches large population simultaneously
• Methods: Radio, TV, newspapers, posters, films, social media, street plays (nukkad natak)
• Cannot address individual needs

• Captive audience; habits formed early
• Integration into curriculum

• Occupational health education
• Targets working population

• Direct (face-to-face): Most effective; immediate feedback
• Indirect (mass media): Wide reach; no immediate feedback

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28. LATHYRISM

• Neurotoxin: BOAA (β-N-oxalyl amino-L-alanine) - an excitatory neurotoxin
• Affects upper motor neurons → spastic paraparesis

• Endemic in Madhya Pradesh, Bihar, UP (India)
• Occurs during famines when people subsist on khesari dal
• Affects primarily young males (18-45 years)
• "Famine food" disease

• Sudden onset of leg weakness after exertion/cold/rain
• Bilateral spastic paralysis of lower limbs (upper limbs spared)
• Scissor gait (crosses legs while walking)
• Hyperreflexia, clonus, extensor plantar response
• No sensory loss; bladder normal initially
• Irreversible once established

• Ban on cultivation and sale of khesari dal
• Detoxification: Soaking, parboiling, roasting reduces toxin
• Food security programs to prevent dependence on khesari dal
• Nutritional alternatives
• Legislation in India prohibiting sale of khesari dal

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29. OCCUPATIONAL HAZARDS OF AGRICULTURAL WORKERS

• Pesticide poisoning - Organophosphates (inhibit acetylcholinesterase), carbamates, organochlorines
• Symptoms: Salivation, miosis, bradycardia, convulsions (acute); chronic: neuropathy, carcinogenesis
• Fertilizer exposure (nitrates - methemoglobinemia)

• Zoonotic diseases: Leptospirosis (rice field workers), brucellosis, tetanus
• Parasitic diseases: Hookworm (walking barefoot), ascariasis
• Vector-borne: Malaria, Japanese encephalitis

• Heat stress: Heat stroke, dehydration (outdoor work in hot sun)
• Musculoskeletal disorders: Back pain (stooping, carrying loads), joint problems
• UV radiation: Skin cancers, cataracts
• Injuries from farm machinery and tools

• Poor posture while paddy transplanting, weeding
• Heavy lifting and carrying
• Repetitive strain injuries

• Crop failure stress, debt, farmer suicides
• Long working hours, seasonal unemployment

• Safe pesticide handling training
• Protective clothing and equipment
• Safe water supply in fields
• Regular health check-ups
• Pest management alternatives (IPM)

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30. EUGENICS AND EUTHENICS

• Positive Eugenics: Encourage reproduction of genetically "fit" individuals
• Negative Eugenics: Discourage reproduction of genetically "unfit" individuals (sterilization, restrictions)

• Genetic counseling
• Genetic screening (prenatal diagnosis)
• Sterilization of carriers
• Regulation of marriage

• Negative eugenics is unethical and was misused (Nazi Germany)
• Modern genetics focuses on disease prevention, not racial improvement
• Genetic counseling is non-directive

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• Improving housing, sanitation, nutrition
• Education and social reform
• Better working conditions
• Control of communicable diseases
• Environmental hygiene

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31. MEASURES OF CENTRAL TENDENCY

• Sum of all values divided by number of values
• Mean (x̄) = Σx/n
• Uses all observations; most commonly used
• Affected by extreme values (outliers)
• Used with normally distributed quantitative data

• Middle value when data arranged in ascending order
• For n values: Median = (n+1)/2 th value
• Not affected by extreme values
• Used with skewed distributions or ordinal data
• More representative when outliers present

• Most frequently occurring value in a data set
• May have no mode, one mode (unimodal), or two modes (bimodal)
• Not affected by extreme values
• Used with nominal/categorical data
• May not be unique

• Symmetrical distribution: Mean = Median = Mode
• Positively skewed: Mode < Median < Mean
• Negatively skewed: Mean < Median < Mode

• Mean age, mean weight, mean income
• Median income (for skewed distributions)
• Mode - most common disease, most common symptom

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32. EPIDEMIOLOGICAL TRIAD

• Biological: Bacteria, viruses, parasites, fungi
• Chemical: Poisons, allergens, drugs
• Physical: Heat, radiation, trauma
• Nutritional: Deficiencies, excesses
• Must be present in sufficient quantity at the right time

• Intrinsic factors affecting susceptibility
• Age, sex, genetic constitution
• Immunological status
• Nutritional status, behavior, habits
• Psychological factors

• External conditions
• Physical: Climate, geography, housing, water, air
• Biological: Vectors, reservoirs, other organisms
• Social: Poverty, education, occupation, customs, beliefs

• Agent has sufficient virulence/dose
• Host is susceptible
• Environment favors agent transmission to host

• Oversimplified for chronic diseases
• Doesn't account for multiple causation
• Led to web of causation model (MacMahon) for complex diseases like CHD

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33. ICEBERG PHENOMENON (see Q.16)

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34. PRIMARY PREVENTION

• Non-specific; raises general health level
• Health education
• Adequate nutrition
• Attention to personality development
• Provision of adequate housing, recreation
• Provision of income and employment
• Genetic counseling

• Directed against specific diseases
• Immunization - vaccines against infectious diseases
• Chemoprophylaxis - anti-malarial drugs, isoniazid for TB contacts
• Environmental sanitation - safe water, sanitation
• Occupational safety - protective equipment, dust control
• Accident prevention - seat belts, helmets
• Avoidance of allergens
• Protection from carcinogens - avoid tobacco, occupational carcinogens
• Specific nutrients - iodized salt, vitamin A supplementation

1. Health promotion
2. Specific protection
3. Legislative action
4. Engineering controls
5. Economic interventions
6. Social interventions

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35. METHODS OF PURIFICATION OF WATER ON SMALL SCALE

1. Storage and Sedimentation:
   • Store water for 24-48 hours - most suspended particles settle
   • Does not kill pathogens; only reduces turbidity
2. Filtration:
   • Slow sand filter (most commonly used)
   • Removes 99.9% bacteria through Schmutzdecke (biological layer)
   • Rate: 0.1-0.4 m³/m²/hour
3. Boiling:
   • Kills all pathogens; 1 minute of rolling boil sufficient
   • Most reliable household method

1. Chlorination:
   • Bleaching powder: 2.5 mg/L chlorine demand + 0.5 mg/L residual
   • Double Pot Method for small scale
   • Horrock's test for residual chlorine
2. Potassium Permanganate (KMnO4):
   • Small quantities for household use
   • Pink color indicates adequate treatment
3. Iodine:
   • 2 drops of 2% iodine per liter; effective against bacteria, viruses, cysts

1. Coagulation + Sedimentation + Filtration + Chlorination:
   • Alum (1-2 mg/L) → coagulation → settling → filtration → chlorination
   • Standard small-scale treatment sequence
2. Solar Disinfection (SODIS): (see Q.26)

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36. USES OF SCREENING TEST

1. Early Detection of Disease:
   • Identify disease before symptoms appear
   • Interrupt natural history at pre-symptomatic stage
   • Examples: Pap smear for cervical cancer, mammogram for breast cancer
2. Reduce Morbidity and Mortality:
   • Early treatment more effective; better prognosis
   • Prevents progression to severe disease
3. Identify Risk Factors:
   • Hypertension screening; hypercholesterolemia screening
   • Enables primary prevention interventions
4. Prevalence Estimation:
   • Determine disease burden in community
   • Plan health services
5. Control of Communicable Diseases:
   • Contact tracing; identify carriers
   • Blood bank screening (HIV, HBsAg, HCV)
6. Newborn Screening:
   • PKU, congenital hypothyroidism, hemoglobinopathies
   • Prevents irreversible disability
7. Occupational Health:
   • Pre-employment and periodic screening of workers
   • Early detection of occupational diseases
8. Research Purposes:
   • Study natural history of disease
   • Evaluate interventions

• Mass screening
• Selective (targeted) screening
• Multiphasic screening (multiple tests simultaneously)
• Opportunistic screening

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37. DRUG ABUSE

1. Opioids - Heroin, morphine, opium, codeine
2. Cannabis - Marijuana, hashish, charas, ganja
3. Depressants - Benzodiazepines, barbiturates, alcohol
4. Stimulants - Cocaine, amphetamines
5. Hallucinogens - LSD, PCP
6. Inhalants - Solvents, glue
7. Prescription drugs - Tramadol, buprenorphine misuse

• Compulsive drug-seeking behavior
• Loss of control over use
• Withdrawal symptoms on stopping
• Tolerance (needing more for same effect)
• Neglect of work, family, social responsibilities
• Continued use despite harm

• Needle marks (IV drug users)
• Pinpoint pupils (opioids)
• Dilated pupils (stimulants)
• Jaundice (hepatitis), weight loss, poor hygiene

• HIV/AIDS, hepatitis B, C (IV drug use)
• Overdose deaths
• Criminal activity, violence
• Family breakdown

• Primary: Education in schools, media campaigns, life skills training
• Secondary: Early identification and treatment (de-addiction centers)
• Tertiary: Rehabilitation, relapse prevention, naltrexone therapy

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38. INTEGRATED VECTOR CONTROL MEASURES

1. Chemical Control:
   • Insecticides: DDT (indoor residual spraying), malathion, pyrethroids
   • Larvicides: Temephos, Abate for mosquito larvae
   • Insect growth regulators
2. Biological Control:
   • Larvivorous fish (Gambusia, Guppy) in water bodies
   • Bacillus thuringiensis israelensis (Bti) - bacterial larvicide
   • Bacillus sphaericus
   • Copepods (for Cyclops control in Guinea worm)
3. Environmental Management:
   • Source reduction: Eliminate breeding sites
   • Drainage of stagnant water
   • Filling and leveling of pits
   • Proper solid waste disposal
4. Personal Protection:
   • Insecticide-treated bed nets (ITNs/LLINs)
   • Repellents (DEET)
   • Protective clothing
   • Window and door screens
5. Genetic Methods:
   • Sterile insect technique (SIT)
   • Genetically modified mosquitoes (Oxitec)
6. Legislative Measures:
   • Anti-larval measures enforced
   • Construction codes for water tanks

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39. IMPACT OF ENVIRONMENTAL SANITATION ON HEALTH

• Safe water supply prevents cholera, typhoid, hepatitis A, dysentery
• Proper sanitation reduces fecal-oral transmission
• Every rupee invested in water and sanitation yields economic benefits

• Elimination of stagnant water reduces malaria, dengue
• Proper drainage reduces vector breeding
• Solid waste management reduces rodent-borne diseases

• Safe disposal of excreta prevents hookworm, ascariasis, tetanus
• Open defecation causes significant disease burden (India: Swachh Bharat Mission)

• Proper food storage and handling prevents food poisoning
• Hygienic slaughterhouses, markets

• Well-ventilated houses reduce respiratory diseases
• Overcrowding promotes TB, meningitis
• Clean cooking fuel reduces indoor air pollution

• Industrial emission control reduces respiratory diseases, lung cancer
• Vehicle emission standards

• % population with safe water access
• % with sanitary latrines
• % open defecation free villages

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40. WEB OF CAUSATION FOR MYOCARDIAL INFARCTION

Heredity/Genetics
    ↓
Hyperlipidemia → Atherosclerosis → Coronary Artery Disease → MYOCARDIAL INFARCTION
    ↑                ↑                   ↑
Obesity         Hypertension        Coronary thrombosis
    ↑                ↑                   ↑
Physical        Stress/Type A       Platelet aggregation
inactivity      personality             ↑
    ↑                                   Smoking
Diet (high fat/salt)                    ↑
    ↑                               Oral contraceptives
Diabetes mellitus

• Non-modifiable: Age (>45 men, >55 women), male sex, family history
• Modifiable:
  • Hyperlipidemia (high LDL, low HDL)
  • Hypertension
  • Diabetes mellitus
  • Cigarette smoking
  • Obesity (BMI >30)
  • Physical inactivity
  • Psychological stress, Type A personality
  • Alcohol (heavy use)

• Identifies multiple intervention points
• Population strategy targets all risk factors
• Primordial + primary + secondary prevention all applicable

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41. HEALTH INFORMATION SYSTEM (HIS)

1. Data collection
2. Data processing and analysis
3. Data storage
4. Information retrieval
5. Information dissemination and use

1. Civil registration system (births, deaths - vital registration)
2. Hospital/clinic records and health facility data
3. Disease surveillance systems (IDSP - Integrated Disease Surveillance Programme)
4. Surveys (NFHS, DLHS, census)
5. Sample Registration System (SRS)
6. Demographic surveys
7. Research and special studies
8. Environmental monitoring data

1. Planning and priority setting in health services
2. Resource allocation
3. Monitoring and evaluation of health programs
4. Disease surveillance and outbreak detection
5. Policy formulation
6. Research
7. International reporting (WHO)
8. Medico-legal purposes

• Completeness, accuracy, timeliness
• Accessibility and usability
• Integration across levels (sub-center to national)
• Regular feedback to data providers

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42. MORBIDITY INDICATORS

1. Incidence Rate:
   • New cases per 1000/100,000 population per unit time
   • Measures risk of developing disease
2. Prevalence Rate:
   • All existing cases (new + old) per population at a point in time
   • Point prevalence vs. period prevalence
   • Relationship: Prevalence ≈ Incidence × Duration
3. Attack Rate:
   • % of population exposed that develops disease
   • Used in epidemics/outbreaks
4. Secondary Attack Rate:
   • Rate among household contacts following primary case
   • Measures communicability
5. Case Fatality Rate (CFR):
   • % of diseased people who die
   • Measures disease severity
6. Hospitalization Rates:
   • Admission rate per 1000 population
7. Disability Rates:
   • Days of restricted activity, work disability
   • DALY (Disability-Adjusted Life Years)
8. Notification Rate:
   • Notifiable diseases reported per 100,000 population
9. Bed Occupancy Rate:
   • Indicator of health service utilization
10. Proportional Morbidity Rate:
    • Proportion of all illness attributable to specific disease

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43. SYMPTOMS OF DRUG ADDICTION AND PREVENTION

• Compulsive drug seeking
• Loss of control over use
• Spending excessive time obtaining/using drugs
• Neglecting responsibilities (work, school, family)
• Continuing use despite knowledge of harm
• Stealing, lying to obtain drugs

• Tolerance (needing increasing doses)
• Withdrawal on stopping:
  • Opioid withdrawal: Sweating, diarrhea, gooseflesh, pain
  • Alcohol withdrawal: Tremors, seizures, delirium
  • Benzodiazepine withdrawal: Anxiety, seizures
• Weight loss, malnutrition
• Injection marks, abscesses (IV users)
• Poor personal hygiene

• Craving
• Depression, anxiety
• Mood swings
• Paranoia (stimulants)
• Cognitive impairment

• School-based drug education (DARE programs)
• Life skills training for adolescents
• Media campaigns
• Reducing availability (law enforcement)
• Community programs

• Early identification
• De-addiction counseling
• Opioid Substitution Therapy (buprenorphine/methadone)
• Brief intervention in primary care

• Rehabilitation centers
• Narcotics Anonymous (NA) groups
• Relapse prevention medications (naltrexone)
• Vocational rehabilitation

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44. SEWAGE AND MODERN SEWAGE TREATMENT PLANT

• BOD (Biochemical Oxygen Demand): Oxygen required to stabilize organic matter (raw sewage: 200-400 mg/L; clean water: <2 mg/L)
• COD (Chemical Oxygen Demand)
• Suspended solids, pH, coliforms

• Screening - removes large solids (rags, sticks)
• Grit chamber - removes sand, gravel
• Flow measurement

• Plain sedimentation in settling tanks
• Removes 30-40% BOD, 50-60% suspended solids
• Sludge settles at bottom (primary sludge)
• Effluent goes to secondary treatment

• Trickling Filter: Effluent trickled over stones coated with bacteria; BOD reduced 80-90%
• Activated Sludge Process: Aeration tanks with sewage + recirculated sludge; microorganisms oxidize organic matter
• Reduces BOD to 20-30 mg/L

• Sludge digestion (anaerobic) - produces biogas (methane)
• Sludge drying and disposal

• Filtration, chemical treatment
• Removal of nutrients (nitrogen, phosphorus)

• Chlorination of final effluent
• UV treatment

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45. EVALUATION OF SCREENING TEST

1. Sensitivity:
   • Ability to correctly identify true diseased people
   • Sensitivity = TP/(TP+FN) × 100
   • High sensitivity = few false negatives
   • "If disease is present, test is positive"
2. Specificity:
   • Ability to correctly identify true non-diseased people
   • Specificity = TN/(TN+FP) × 100
   • High specificity = few false positives
   • "If no disease, test is negative"
3. Predictive Value Positive (PVP):
   • Proportion of test positives who truly have disease
   • PVP = TP/(TP+FP) × 100
   • Depends on prevalence of disease
4. Predictive Value Negative (PVN):
   • Proportion of test negatives who truly don't have disease
   • PVN = TN/(TN+FN) × 100

• Increasing sensitivity → decreases specificity (more false positives)
• ROC curve used to find optimal cut-off point

• Consistent results on repeated testing
• Measured by Kappa statistic
• Affected by: intra-observer variation, inter-observer variation, biological variation

• Number of previously undiagnosed cases identified per unit of effort
• Depends on: sensitivity of test, prevalence of disease, proportion previously undiagnosed

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46. MEASURES OF DISPERSION (VARIATION)

• Difference between maximum and minimum values
• Range = Maximum - Minimum
• Simple but affected by extreme values
• Example: If ages are 5, 10, 15, 20, 25 → Range = 25-5 = 20

• Average of absolute deviations from mean
• MD = Σ|x - x̄|/n
• Rarely used in practice

• Average of squared deviations from mean
• σ² = Σ(x - x̄)²/(n-1)
• Units are squared - not directly interpretable

• Square root of variance
• Most important measure of dispersion
• σ = √[Σ(x - x̄)²/(n-1)]
• Same units as original data
• In normal distribution: Mean ± 1SD = 68.27%; ±2SD = 95.45%; ±3SD = 99.73%

• SE = SD/√n
• Measures precision of sample mean
• Used in confidence intervals and hypothesis testing

• CV = (SD/Mean) × 100
• Compares variability between different units/populations
• Example: Comparing variability in weight vs. height

• Interquartile Range (IQR) = Q3 - Q1
• Not affected by extreme values
• Used in box plots

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47. EFFECTS AND CONTROL OF NOISE EXPOSURE

• Occupational: 85 dB (A) for 8 hours (OSHA)
• Community: 45 dB (day), 35 dB (night) - WHO

1. Temporary Threshold Shift (TTS): Temporary hearing loss; recovers after rest
2. Permanent Threshold Shift (PTS)/Noise-Induced Hearing Loss (NIHL):
   • Irreversible sensorineural hearing loss
   • Begins at 4000 Hz (audiometric notch)
   • Progresses to conversational frequencies
3. Acoustic trauma: Sudden exposure to very loud noise

1. Cardiovascular: Hypertension, tachycardia, peripheral vasoconstriction
2. Hormonal: Increased cortisol, catecholamines (stress response)
3. Sleep disturbance: Chronic sleep deprivation
4. Psychological: Irritability, stress, anxiety, reduced productivity
5. Gastrointestinal: Peptic ulcer (chronic stress)
6. Interference with communication: Masking speech

1. Engineering Controls (at source):
   • Equipment redesign, vibration dampening
   • Enclosure of noisy machines
   • Sound barriers, acoustic panels
2. Administrative Controls:
   • Job rotation to limit exposure duration
   • Scheduling noisy work at low-occupancy times
3. Personal Protective Equipment:
   • Ear muffs, ear plugs (reduce 20-40 dB)
   • Must be properly fitted
4. Medical Measures:
   • Pre-employment audiometry
   • Periodic audiometric surveillance
   • Early detection and removal from exposure
5. Legislative Measures:
   • Noise Pollution (Regulation and Control) Rules, 2000 (India)
   • OSHA standards

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48. PREVENTION OF MENTAL ILLNESS

1. Health Promotion:
   • Mental health education in schools and community
   • Parenting skills programs
   • Stress management techniques
   • Promoting social support networks
2. Specific Protection:
   • Prevention of organic causes:
     • Rubella vaccination (prevent congenital rubella-associated mental illness)
     • Iodine supplementation (prevent cretinism/mental retardation)
     • Lead hazard control (lead poisoning affects brain)
     • Prevention of birth injuries
   • Genetic counseling for hereditary mental disorders
   • Prevention of substance abuse

1. Early case detection through community mental health workers
2. Screening programs for depression, schizophrenia
3. Prompt treatment - availability of psychotropic drugs at PHC level
4. Crisis intervention services
5. Suicide prevention hotlines

1. Rehabilitation of chronic mental patients
2. Day care centers, halfway homes
3. Vocational training and sheltered workshops
4. Family education and support
5. Prevention of stigma and discrimination

• Mental Healthcare Act 2017 (India) - ensures rights of persons with mental illness
• National Mental Health Policy 2014
• NMHP and DMHP for service delivery

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49. SAMPLING METHODS

1. Simple Random Sampling:
   • Every unit has equal chance of selection
   • Methods: Lottery method, random number tables
   • Unbiased; requires complete sampling frame
2. Systematic Random Sampling:
   • Every k-th unit selected (k = N/n)
   • Simple and practical
   • Risk: Periodicity bias
3. Stratified Random Sampling:
   • Population divided into strata (age, sex, social class)
   • Random sample from each stratum
   • More representative; reduces sampling error
   • Proportional vs. disproportional allocation
4. Cluster Sampling:
   • Population divided into clusters (villages, blocks)
   • Clusters randomly selected; all members included
   • Used in large surveys (e.g., 30x7 EPI coverage survey)
   • Cost-effective; requires larger sample
5. Multistage Sampling:
   • Multiple stages of sampling (state → district → village → household)
   • Used in NFHS, NSS surveys

1. Convenience Sampling: Select whoever is available; biased
2. Purposive Sampling: Deliberate selection based on judgment
3. Quota Sampling: Fixed quota from each subgroup
4. Snowball Sampling: Used for hard-to-reach populations

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50. MODES OF INTERVENTION IN PREVENTION OF DISEASE

1. Immunization - Specific protection against infectious diseases
2. Chemoprophylaxis - Drug prophylaxis (anti-malarials, INH for TB)
3. Health education - Behavior change communication
4. Nutritional interventions - Supplementation, fortification
5. Genetic counseling - Prevention of hereditary diseases

1. Safe water supply - Chlorination, purification
2. Sanitation - Sewage disposal, solid waste management
3. Vector control - IRS, bed nets, source reduction
4. Food safety - Inspection, food laws
5. Air pollution control - Emission standards

1. Legislative measures - Laws against tobacco, alcohol, food adulteration
2. Economic interventions - Tax on tobacco, sugar-sweetened beverages
3. Social marketing - Condom promotion, ORS use
4. Community mobilization - Village health committees

• Primary - Before disease (health promotion + specific protection)
• Secondary - Early disease (screening + treatment)
• Tertiary - Established disease (disability limitation + rehabilitation)

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51. DEFINE BALANCE (Dietary Balance)

• Positive balance → weight gain (energy in > energy out)
• Negative balance → weight loss (energy out > energy in)
• Balance → stable weight

• Nitrogen balance:
  • Positive: Protein intake > protein loss (growth, pregnancy)
  • Negative: Protein loss > intake (illness, starvation, burns)
  • Equilibrium: Adult on adequate protein diet

• Normal blood pH: 7.35-7.45
• Maintained by bicarbonate buffer, respiratory, and renal systems

• Intake (water + food) = Output (urine + feces + sweat + insensible loss)
• ~2.5 liters/day in/out in adults

• Na+, K+, Ca2+, Mg2+ maintained within narrow limits
• Hormonal control (aldosterone, ADH, PTH)

• Balanced diet provides all nutrients in right amounts
• ICMR recommended dietary allowances (RDA) guide dietary balance
• Imbalance causes both deficiency diseases and diseases of excess

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52. PREVENTIVE MEASURES FOR PROTEIN ENERGY MALNUTRITION (PEM)

1. Promotion and support of exclusive breastfeeding for 6 months
2. Appropriate complementary feeding from 6 months
3. Locally available, low-cost, energy-dense complementary foods
4. Kitchen gardens for vegetable/fruit access
5. Animal protein sources when feasible (eggs, milk, fish)

1. Growth monitoring at Anganwadi centers (weight-for-age charts)
2. Regular weighing and early identification of faltering growth
3. Treatment of infections (diarrhea, ARI, parasites worsen PEM)
4. Oral Rehydration Therapy for diarrhea
5. Micronutrient supplementation (Vitamin A, iron, zinc)

1. ICDS program - supplementary nutrition through Anganwadi
2. Mid-day meal programs
3. Food distribution programs (PDS - Public Distribution System)
4. MGNREGA (economic security → food security)

1. Educate mothers on infant feeding practices
2. Dispel myths about food taboos
3. Hygiene education to reduce infections

1. Nutritional Rehabilitation Centers (NRC) for severe acute malnutrition
2. RUTF (Ready-to-Use Therapeutic Food) - Plumpy'Nut

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53. ROLE OF DOCTOR IN EFFECTIVE COMMUNICATION

1. Use simple, understandable language (avoid jargon)
2. Active listening - let patient complete their complaint
3. Open-ended questions first, then closed-ended
4. Repeat and summarize key information
5. Provide clear instructions about treatment

1. Eye contact - shows attention and empathy
2. Appropriate posture - lean slightly toward patient
3. Facial expression - empathetic, non-judgmental
4. Physical distance - appropriate proxemics
5. Nodding to show listening

1. Build rapport and trust from the start
2. Take thorough history (including psychosocial aspects)
3. Explain diagnosis and treatment in understandable terms
4. Assess patient understanding (teach-back method)
5. Address patient's concerns and fears
6. Maintain confidentiality
7. Provide written instructions when needed
8. Show empathy - acknowledge emotions

• Time constraints
• Language differences (use interpreter if needed)
• Patient's emotional state (fear, anxiety)
• Cultural differences

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54. CULTURAL FACTORS INFLUENCING HEALTH AND DISEASE

1. Cleanliness rituals (Hindu practice of bathing)
2. Certain food preparation methods
3. Community support systems in joint families
4. Breastfeeding practices in some cultures

1. Dietary Taboos:
   • Eggs/meat avoided in illness (deprives protein)
   • Girls given less food than boys in some cultures
   • Pregnant women avoided nutritious foods (fish, eggs in some tribes)
2. Health-seeking Behavior:
   • Preference for traditional healers over modern medicine
   • Delayed health-seeking due to fatalism
   • Reliance on faith healing
3. Hygiene Practices:
   • Open defecation (cultural norm in rural India)
   • Unsafe delivery practices (traditional birth attendants)
4. Social Practices:
   • Female genital mutilation
   • Early marriage → teen pregnancy risks
   • Preference for male children → female infanticide
5. Stigma:
   • Mental illness, leprosy, HIV/AIDS - cultural stigma prevents treatment
6. Marriage Customs:
   • Consanguineous marriages → genetic disorders
   • Endogamy in some communities

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55. BIOCHEMICAL TESTS IN NUTRITIONAL SURVEYS

1. Hemoglobin Estimation:
   • Diagnosis of anemia
   • Normal: Men >13 g/dL; Women >12 g/dL; Children >11 g/dL
   • Methods: Sahli's, Cyanmethemoglobin (gold standard)
2. Serum Albumin:
   • Protein status indicator
   • Normal: 3.5-5.0 g/dL
   • Low in kwashiorkor and protein deficiency
   • Long half-life (20 days) - not good for acute changes
3. Serum Retinol (Vitamin A):
   • Normal: >20 μg/dL (>0.70 μmol/L)
   • Deficient: <10 μg/dL
   • Relative Dose Response (RDR) test
4. Urinary Iodine Concentration:
   • Indicator of iodine status
   • Normal: 100-299 μg/L
   • Deficient: <100 μg/L (mild: 50-99; moderate: 20-49; severe: <20)
5. Serum Ferritin:
   • Best indicator of iron stores
   • Normal: 15-200 ng/mL
   • Low (<12 ng/mL) indicates iron deficiency
6. Serum Zinc:
   • Normal: 70-120 μg/dL
   • Indicator of zinc deficiency
7. Urinary Creatinine Height Index:
   • Assesses muscle mass/protein nutritional status
8. Blood Glucose:
   • Nutritional diabetes assessment

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56. ASSESSMENT OF DIETARY INTAKE AND ANTHROPOMETRY IN PRESCHOOL CHILDREN

1. 24-hour Dietary Recall:
   • Parent/caregiver recalls all food consumed in 24 hours
   • Quick and easy
   • Subject to memory error; single day may not represent usual intake
2. Food Frequency Questionnaire (FFQ):
   • Frequency of consumption of specific foods over a period
   • Semi-quantitative
   • Good for epidemiological studies
3. Dietary History Method:
   • Detailed account of usual dietary patterns
   • More comprehensive than single recall
4. Weighed Food Record:
   • Precise measurement of all food items
   • Most accurate; but burdensome
5. Dietary Diversity Score:
   • Number of food groups consumed

• Weight - most sensitive indicator of current nutritional status
• Height/Length - reflects long-term nutritional status
• Mid-Upper Arm Circumference (MUAC) - indicator of muscle mass; used for SAM screening (<11.5 cm = SAM; 11.5-12.5 cm = MAM)
• Head circumference - brain growth indicator
• Skinfold thickness - fat stores

1. Weight-for-Age (WFA): Underweight (reflects composite)
2. Height-for-Age (HFA): Stunting (chronic malnutrition)
3. Weight-for-Height (WFH): Wasting (acute malnutrition)

• < -2 SD: Moderate malnutrition
• < -3 SD: Severe malnutrition

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57. ADVERSE EVENTS FOLLOWING IMMUNIZATION (AEFI)

1. Vaccine Product-Related Reactions:
   • Caused by inherent properties of vaccine
   • Example: Febrile seizures with whole-cell pertussis vaccine
2. Vaccine Quality Defect-Related Reactions:
   • Due to manufacturing defect or deviation
   • Example: Vaccine given as bolus instead of slow injection
3. Immunization Error-Related Reactions:
   • Due to improper handling, preparation, or administration
   • Wrong site, wrong dose, wrong vaccine, non-sterile technique
   • Example: Abscess at injection site from improper technique
4. Immunization Anxiety-Related Reactions:
   • Psychological response to needle/injection
   • Vasovagal syncope, hyperventilation
5. Coincidental Events:
   • Would have occurred regardless of vaccination
   • Temporal association but not causal

• Sore arm, local redness, swelling (most common)
• Fever
• BCG lymphadenitis
• VAPP (Vaccine-Associated Paralytic Polio) with OPV
• Anaphylaxis (rare but serious)
• Intussusception (Rotavirus vaccine - risk in older infants)

• For mild reactions: Reassure, symptomatic treatment
• For anaphylaxis: Adrenaline 1:1000 (0.01 mg/kg IM)
• Causality assessment and reporting to AEFI committee

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58. CONCEPT OF WELL-BEING

1. Physical Well-being:
   • Absence of disease
   • Adequate nutrition, fitness, functional capacity
   • Physical comfort
2. Mental/Psychological Well-being:
   • Positive sense of self, self-esteem
   • Emotional resilience, coping ability
   • Absence of mental disorders
   • Life satisfaction, happiness
3. Social Well-being:
   • Ability to maintain social roles
   • Good interpersonal relationships
   • Social support networks
   • Community integration
4. Spiritual Well-being:
   • Sense of meaning and purpose
   • Cultural and spiritual fulfilment
5. Environmental Well-being:
   • Safe and clean environment
   • Adequate housing, sanitation

• Well-being = "a state of complete ease and contentment"
• Well-being goes beyond clinical health
• Measured by health indicators: life expectancy, disability-free life years, quality-adjusted life years (QALYs)

• Wellness - dynamic process of moving toward higher levels of health
• Salutogenesis (Antonovsky) - factors that create health

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59. QUARANTINE vs. ISOLATION

1. Absolute quarantine: Complete restriction - same limitations as isolation
2. Modified quarantine: Selective restrictions (e.g., exclusion from food handling)
3. Personal surveillance: Daily reporting to health officer; no restrictions
4. Segregation: Separation of part of group (e.g., children from adults)

• Quarantine: Chicken pox contacts kept home for 21 days (max incubation)
• Isolation: Active TB patient on DOTS kept away from contacts initially

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60. DEFINITION OF SCREENING AND SCREENING vs. DIAGNOSTIC TESTS

1. Mass screening - Entire population screened
2. Selective screening - High-risk groups only
3. Multiphasic screening - Multiple tests simultaneously
4. Opportunistic screening - During routine clinical contacts

• Applied to asymptomatic/healthy people
• Identifies "suspects"
• Simple, cheap, safe, rapid
• High sensitivity desired
• Positive result → needs follow-up diagnostic test

• Applied to symptomatic or screen-positive individuals
• Confirms or rules out disease
• May be complex, expensive, invasive
• High specificity desired
• Leads to treatment decision

1. Condition should be important health problem
2. Acceptable treatment available
3. Facilities for diagnosis/treatment available
4. Recognizable latent/early symptomatic stage
5. Suitable test available
6. Test acceptable to population
7. Natural history understood
8. Agreed treatment policy
9. Cost-benefit analyzed
10. Ongoing process (not one-time)

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61. DISEASES DUE TO DUST EXPOSURE AND BYSSINOSIS

• Cotton/flax/hemp dust
• Endotoxin from gram-negative bacteria in vegetable dust is the likely cause
• Bronchoconstriction mechanism

• Grade 0: No symptoms
• Grade 1/2: Chest tightness on first day of working week (Monday); clears by afternoon
• Grade 1: Tightness on first day of every week
• Grade 2: Tightness on first day + other days
• Grade 3: Permanent respiratory disability (irreversible - emphysema, chronic bronchitis)

• Dust suppression at source (wetting, exhaust ventilation)
• Reduction of dust levels (<0.5 mg/m³ for cotton dust)
• PPE (respiratory protection)
• Pre-employment and periodic medical examination

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62. ATTRIBUTABLE RISK, RELATIVE RISK, POPULATION ATTRIBUTABLE RISK

• Ratio of incidence in exposed to incidence in unexposed
• RR = Ie / Iu (Ie = incidence in exposed; Iu = incidence in unexposed)
• Measures strength of association
• RR = 1: No association; RR > 1: Positive association; RR < 1: Protective
• Example: If smokers have 10% lung cancer incidence and non-smokers 1% → RR = 10

• Excess risk in exposed due to the exposure
• AR = Ie - Iu
• Measures absolute excess risk
• Tells how much disease in exposed is attributable to the exposure
• Example: AR = 10% - 1% = 9% (9% of lung cancer in smokers is due to smoking)

• Excess disease in total population due to the exposure
• PAR = Ip - Iu (Ip = incidence in total population)
• Measures public health impact of exposure
• Depends on both RR and prevalence of exposure in population

• RR: Etiological importance
• AR: Clinical importance (individual benefit from eliminating exposure)
• PAR: Public health priority (benefit to community from removing exposure)

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63. VITAMIN A DEFICIENCY DISORDERS

• XN: Night blindness (Nyctalopia) - first sign
• X1A: Conjunctival xerosis (dry, dull conjunctiva)
• X1B: Bitot's spots (foamy, triangular white patches on conjunctiva)
• X2: Corneal xerosis
• X3A: Corneal ulceration (< 1/3 cornea)
• X3B: Keratomalacia (> 1/3 cornea) - blinding
• XS: Corneal scar (Leukoma)
• XF: Xerophthalmic fundus

1. Increased susceptibility to infections (respiratory, diarrhea)
2. Impaired immune function (reduced lymphocyte proliferation)
3. Growth failure
4. Anemia (VA affects erythropoiesis)
5. Dry skin (follicular hyperkeratosis)
6. Increased child mortality

• Most common in preschool children (6 months - 6 years)
• Significant in South/Southeast Asia, Sub-Saharan Africa
• VADD is leading cause of preventable blindness in children

• Vitamin A supplementation program
• 9 months: 1 lakh IU oral
• 1-5 years: 2 lakh IU every 6 months

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64. STEPS TO REDUCE BURDEN OF VITAMIN A DEFICIENCY

• Mass supplementation to all children 6 months - 5 years
• Universal Immunization Program (UIP) delivery
• Dose: 1 lakh IU at 9 months (with measles); 2 lakh IU 6-monthly thereafter
• Safe upper limit: 10× RDA is safe; mega-doses can cause toxicity

• Promote consumption of vitamin A-rich foods
• Dark green leafy vegetables (amaranth, spinach, drumstick leaves)
• Orange/yellow fruits and vegetables (mango, papaya, carrots, sweet potato)
• Animal sources (egg yolk, liver, milk, fish)
• Kitchen gardens and animal husbandry promotion

• Fortify widely consumed foods with vitamin A
• Vanaspati/edible oils fortified with Vitamin A (India - mandatory)
• Sugar fortification (some countries)
• FSSAI standards for fortification

• Educate mothers on vitamin A-rich complementary foods
• Promotion of breastfeeding (colostrum rich in vitamin A)
• Dispel food taboos

• Treatment of diarrhea, respiratory infections
• Deworming (worms reduce absorption)
• Malaria control

• Regular national surveys to assess VADD burden
• Serum retinol surveys

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65. DISEASES TRANSMITTED BY RODENTS + ANTI-RODENT MEASURES

• Proper construction (no gaps in walls, floors)
• Elimination of harbourage sites (burrows, clutter)
• Proper storage of food in rat-proof containers
• Sanitary disposal of garbage
• Regular inspection of premises

• Anticoagulants: Warfarin, bromadiolone (first and second generation)
  • Multi-dose feeding required (tolerance develops)
• Acute rodenticides: Zinc phosphide (most common in India), brodifacoum
  • Single dose; use with caution (secondary poisoning risk)
• Bait stations in strategic locations

• Cats (domestic)
• Natural predators

• Mechanical traps (snap traps, cage traps)

• Coordinated rat control in areas (not just individual houses)
• Community sanitation drives

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66. GREENHOUSE EFFECT

• Natural: Essential for life; maintains Earth at ~15°C (without it would be -18°C)
• Enhanced/Anthropogenic: Due to increased GHG emissions → global warming

• Carbon dioxide (CO2) - 60%
• Methane (CH4) - 20%
• Nitrous Oxide (N2O)
• CFCs (Chlorofluorocarbons)
• Water vapor (H2O)

1. Solar radiation (short wavelength) passes through atmosphere
2. Earth absorbs and radiates as infrared (long wavelength)
3. GHGs absorb outgoing IR radiation
4. Re-radiate back to Earth surface
5. Net warming effect

• Rising global temperatures (1.1°C above pre-industrial)
• Melting of polar ice caps and glaciers
• Sea level rise (flooding of coastal areas)
• More frequent extreme weather events
• Changes in precipitation patterns
• Ecosystem disruption

• Heat-related illness and deaths
• Spread of vector-borne diseases
• Food and water insecurity
• Air quality deterioration
• Climate refugees and conflict

• Paris Agreement (2015): Limit warming to 1.5-2°C
• Reduce fossil fuel use; renewable energy
• UNFCCC, Kyoto Protocol
• Carbon capture and storage

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67. ENUMERATE SOCIAL FACTORS INFLUENCING HEALTH AND DISEASE

1. Poverty:
   • Direct impact on nutrition, housing, sanitation
   • Inability to afford healthcare
   • Poverty → malnutrition → susceptibility to infections
2. Education:
   • Education correlates with better health outcomes
   • Educated mothers have lower child mortality
   • Health literacy affects health behavior
3. Occupation:
   • Determines income, social class, occupational hazards
   • Blue collar workers → higher exposure to physical/chemical hazards
4. Social Class/Caste:
   • Inequalities in access to healthcare
   • Caste-based discrimination affects health services
5. Cultural Practices:
   • Dietary habits, health-seeking behavior (see Q.54)
   • Religious practices (fasting, dietary restrictions)
6. Family Structure:
   • Joint vs. nuclear family; single-parent households
   • Support during illness
7. Social Support Networks:
   • Strong social networks → better mental health, faster recovery
8. Housing:
   • Overcrowding → TB, respiratory infections
   • Lack of sanitation → diarrheal diseases
9. Urbanization:
   • Slums, pollution, stress of urban life
   • Access to health services (double-edged)
10. Gender Inequality:
    • Women's health affected by discrimination, violence
    • Limited decision-making power
11. Social Cohesion and Trust:
    • Community trust affects program acceptance (vaccination)
12. Migration:
    • Disrupts social networks; exposes to new diseases

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68. MEASURES OF RISK IN COHORT STUDIES

• Proportion of initially disease-free people who develop disease over a defined period
• CI = New cases during period / Population at risk at start

• Rate of new cases per person-time at risk
• IR = New cases / Total person-years of observation
• Used when follow-up varies

• RR = Incidence in exposed / Incidence in unexposed
• RR = Ie / Iu
• Measures strength of association
• RR > 1: Increased risk; RR < 1: Protective

• AR = Ie - Iu
• Absolute excess risk in exposed
• Useful for assessing individual benefit of removing exposure

• AR% = (Ie - Iu)/Ie × 100
• % of disease in exposed due to exposure

• PAR = Ip - Iu
• Excess risk in total population due to exposure
• PAR% = (Ip - Iu)/Ip × 100

• 1/AR
• Number of exposed persons needed for 1 extra case

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69. ADVANTAGES AND DISADVANTAGES OF COHORT STUDY

1. Can calculate incidence rates directly (unlike case-control)
2. Can calculate Relative Risk (RR) - strongest epidemiological measure
3. Temporal sequence clear - exposure precedes disease (no reverse causality)
4. Can study multiple outcomes from a single exposure
5. Minimizes selection bias (selection before disease occurs)
6. Recall bias minimized (exposure assessed before disease)
7. Demonstrates natural history of disease
8. Suitable for common diseases and delayed effects

1. Time-consuming - Prospective cohorts take years to decades
2. Expensive - Large sample, long follow-up
3. Large sample required - Especially for rare outcomes
4. Attrition/Loss to follow-up - Can introduce bias
5. Not suitable for rare diseases - Very large cohort needed
6. Changes in exposure over time - Complicated analysis
7. Healthy worker effect - Biases occupational cohort studies
8. Ethical issues - Cannot study harmful exposures prospectively

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70. STANDARD NORMAL DISTRIBUTION CURVE

1. Symmetrical about the mean
2. Mean = Median = Mode
3. Bell-shaped curve
4. Total area under curve = 1 (or 100%)
5. Tails extend to infinity but never touch x-axis
6. Completely defined by mean (μ) and SD (σ)

• Mean ± 1 SD: 68.27% of observations
• Mean ± 1.96 SD: 95% of observations
• Mean ± 2 SD: 95.45% of observations
• Mean ± 2.58 SD: 99% of observations
• Mean ± 3 SD: 99.73% of observations

• Z = (X - μ)/σ
• Converts any normal distribution to standard normal
• Z-score: number of SDs from mean
• Used in growth charts (WHO Z-scores for nutritional assessment)

1. Reference for biological measurements (height, weight, blood pressure)
2. Quality control
3. Setting reference ranges (mean ± 2SD = 95% reference range)
4. Hypothesis testing (Z-test)
5. Growth monitoring (Z-scores for children)
6. Calculating confidence intervals

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71. ANTHROPOMETRIC INDICES FOR NUTRITIONAL ASSESSMENT IN CHILDREN

• Compares child's weight to reference for same age
• Indicator of: Underweight (reflects composite acute + chronic malnutrition)
• Used in growth monitoring
• < -2 SD: Moderate underweight; < -3 SD: Severe underweight
• Cannot distinguish stunting from wasting

• Compares height to reference for same age
• Indicator of: Stunting (chronic, long-term malnutrition)
• Reflects past nutritional history
• < -2 SD: Moderate stunting; < -3 SD: Severe stunting
• Irreversible if severe in early childhood

• Compares weight to reference for same height (age-independent)
• Indicator of: Wasting (acute, current malnutrition)
• < -2 SD: Moderate acute malnutrition (MAM)
• < -3 SD: Severe acute malnutrition (SAM)
• Most useful for identifying current emergency

• Used for school-age children (5-19 years)
• WHO BMI-for-age charts
• Identifies overweight and obesity in older children

• Measured at mid-point of upper arm
• < 11.5 cm: SAM; 11.5-12.5 cm: MAM; > 12.5 cm: Normal
• Easy to use in field conditions; no weighing scale needed
• Good predictor of mortality risk

• Reflects brain growth
• Important in infancy and early childhood

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72. NEWBORN SCREENING TESTS

1. Congenital Hypothyroidism (CH):
   • TSH on Day 3-5 blood spot (Guthrie card)
   • Most common preventable cause of mental retardation
   • Treated with thyroxine if detected early
2. Phenylketonuria (PKU):
   • Elevated phenylalanine in blood
   • Guthrie bacterial inhibition assay
   • Treated with phenylalanine-restricted diet
3. Congenital Adrenal Hyperplasia (CAH):
   • 17-OH progesterone measurement
4. Hemoglobinopathies:
   • Sickle cell disease, thalassemia
   • Hemoglobin electrophoresis
5. Glucose-6-Phosphate Dehydrogenase Deficiency (G6PD):
   • Enzyme assay
   • Important in India (avoid oxidant drugs)

• Congenital malformations
• Developmental dysplasia of hip (Barlow/Ortolani tests)
• Congenital heart disease (pulse oximetry + examination)
• Cleft lip/palate
• Ophthalmia neonatorum
• Jaundice

1. Hearing screening (DPOAE - Distortion Product OtoacousticEmissions)
2. Vitamin K injection (prevention of hemorrhagic disease of newborn)

• FBNC (Facility Based Newborn Care) under RCH program
• SNCU (Special Newborn Care Units) in district hospitals

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73. ECOLOGICAL FACTORS RELATED TO MALNUTRITION

1. Food Availability:
   • Agricultural productivity (drought, floods, soil quality)
   • Food distribution systems
   • Food storage and preservation
2. Socioeconomic Factors:
   • Poverty → inability to purchase adequate food
   • Unemployment
   • Income inequality
3. Dietary Habits and Practices:
   • Food taboos during pregnancy, lactation
   • Early weaning, inappropriate complementary foods
   • Preference for refined foods
4. Infection Cycle:
   • Infections → malnutrition (increased metabolic needs, anorexia, malabsorption)
   • Malnutrition → increased susceptibility to infection (impaired immunity)
   • Creates vicious cycle (Protein Energy Malnutrition ↔ Infection)
5. Population Dynamics:
   • High birth rate → increased demand on food resources
   • Large family size → less food per child
6. Ignorance and Lack of Education:
   • Mothers unaware of nutritional needs
   • Lack of nutrition education
7. Environmental and Climatic Factors:
   • Seasonal food shortages
   • Natural disasters
8. Political and Governance Factors:
   • War, conflict → food insecurity
   • Poor food distribution policies

• Immediate causes: Inadequate diet + disease
• Underlying causes: Household food insecurity, inadequate care, poor health environment
• Basic causes: Social, economic, political

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74. HEALTH-PROMOTING MEASURES FOR PREVENTION OF PEM IN COMMUNITY

1. Food Security Programs:
   • National Food Security Act (NFSA) 2013 - subsidized food grains
   • Public Distribution System (PDS) - rice, wheat, pulses at subsidized rates
   • MGNREGA - employment guarantee for rural poor
2. Maternal and Child Health Programs:
   • Antenatal care - identify and treat maternal malnutrition
   • JSSK (Janani Shishu Suraksha Karyakram) - free maternal and newborn services
   • Home-based newborn care
3. ICDS Program:
   • Supplementary nutrition at Anganwadi centers (6 days/week)
   • 500 kcal + 12-15 g protein for children; more for SAM children
   • Growth monitoring and promotion
4. Deworming:
   • National Deworming Day (twice yearly for 1-19 years)
   • Albendazole 400 mg single dose
   • Worms cause malabsorption and blood loss → worsens PEM
5. Promotion of Breastfeeding:
   • Baby Friendly Hospital Initiative (BFHI)
   • Exclusive breastfeeding for 6 months
   • Continued breastfeeding till 2 years with complementary feeding
6. Nutrition Education:
   • Community-based nutrition education through ASHAs, AWWs
   • Cooking demonstrations with locally available foods
   • Promotion of dietary diversity
7. Kitchen/Nutrition Gardens:
   • Village-level promotion of vegetable growing
   • Nutri-gardens at schools
8. POSHAN Abhiyaan (2018):
   • Mission to reduce stunting, wasting, underweight, anemia
   • Jan Andolan (People's movement) for nutrition

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75. LIST DIFFERENCE BETWEEN QUARANTINE AND ISOLATION (See Q.59)

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76. IMPORTANCE OF ATTRIBUTABLE RISK, RELATIVE RISK, POPULATION ATTRIBUTABLE RISK (See Q.62)

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77. MEASURES OF VARIATION (See Q.46)

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78. MODES OF INTERVENTION IN PREVENTION OF DISEASE (See Q.50)

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SUMMARY TABLE: QUICK REFERENCE FOR EXAM

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