Prevention of Diabetes Mellitus

1. Understanding the Risk Continuum

• Between 6-10% of patients with impaired glucose tolerance (IGT) progress to clinical diabetes each year; up to 65% of those with both IFG and IGT progress annually.
• A1C of 6.0-6.5% carries a 5-year progression rate of 25-50%.

2. Who to Screen (Risk Factors)

• Obesity (especially abdominal obesity) or BMI >25 kg/m²
• Family history of T2DM in first-degree relative
• Sedentary lifestyle
• History of gestational diabetes mellitus (GDM) or delivery of baby >9 lb
• History of cardiovascular disease
• Hypertension (BP ≥140/90 mmHg)
• Dyslipidemia: HDL <35 mg/dL or triglycerides >250 mg/dL
• Polycystic ovary syndrome (PCOS)
• Non-white ancestry
• Schizophrenia or bipolar disorder (due to antipsychotic use)
• Age >35 years (screen every 3 years)
• HIV medications or glucocorticoid use
• History of pancreatitis

3. Prevention of Type 2 Diabetes

A. Lifestyle Modification (First-Line)

• Randomized subjects with IGT to placebo, metformin, or intensive lifestyle intervention.
• Lifestyle modification reduced progression to T2DM by 58% (NNT = 7 over 3 years to prevent 1 case).
• Metformin reduced progression by 31% (NNT = 14 over 3 years).
• 10-year follow-up: lifestyle arm maintained a 34% relative risk reduction.

Specific Lifestyle Goals (ADA Recommendations):

• Weight loss of 7% from baseline body weight (obese/overweight individuals) - maximal T2DM prevention occurs at 7-10% weight loss, reducing risk by ~80%
• At least 150 minutes per week of moderate aerobic exercise (e.g., brisk walking)
• Dietary changes: caloric restriction with deficit of 500-1000 kcal/day, reduced saturated fat, increased dietary fiber, limited refined carbohydrates, reduced sodium

B. Pharmacotherapy

C. Surgical Prevention

D. Monitoring of Prediabetic Individuals

• Monitor annually for progression to clinical diabetes (HbA1c or fasting glucose)
• Address cardiovascular risk factors:
  • Smoking cessation
  • Target BP <140/90 mmHg (ADA) or <130/80 mmHg (AACE)
  • Target LDL <100 mg/dL with statin therapy
• In women with prior GDM: screen every 3 years

4. Prevention of Type 1 Diabetes

5. Prevention of Gestational Diabetes and Type 3c

• Gestational diabetes: Pre-pregnancy weight management, avoiding excessive gestational weight gain, and physical activity reduce risk. Women with prior GDM should be monitored and offered intensive lifestyle intervention postpartum.
• Pancreatogenic (Type 3c) diabetes: Avoiding alcohol excess and managing chronic pancreatitis reduces risk.

6. Public Health and National Programs

• Health promotion and lifestyle change through mass media
• Opportunistic screening of persons above age 30
• Integration with primary health care systems
• Capacity building at all levels

Summary of Prevention Strategies

PREDIABETES IDENTIFIED
        │
        ├── Lifestyle modification (FIRST LINE)
        │   ├── 7-10% weight loss
        │   ├── ≥150 min/wk moderate exercise
        │   └── Dietary modification
        │
        ├── Pharmacotherapy (if lifestyle insufficient)
        │   ├── Metformin (ADA-endorsed)
        │   └── Others (pioglitazone, acarbose - not routinely recommended)
        │
        ├── CV risk factor management
        │   ├── BP, LDL, smoking
        │
        └── Annual monitoring

Recent Evidence (2025)

VISION 2020: The Right to Sight

1. Background and Launch

2. Mission and Goal

"To eliminate the main causes of blindness in order to give all the people of the world, particularly the millions of needlessly blind, the Right to Sight by the year 2020."

3. Objectives of Vision 2020

1. Raise the profile among key audiences of the causes of avoidable blindness and the solutions to the problem
2. Advocate for and secure the necessary resources to increase prevention and treatment activities
3. Facilitate the planning, development and implementation of national Vision 2020 programmes in all countries
4. Assist member countries in developing sustainable systems to eliminate avoidable blindness from major causes by the year 2020

4. Priority Disease Areas (Target Diseases)

5. Three Core Strategies (Pillars)

A. Disease Control

• Cost-effective interventions targeted at the priority diseases listed above
• Emphasis on community-level disease control for trachoma and onchocerciasis
• Technical working groups established for each disease priority

B. Human Resource Development

• Training of ophthalmologists, ophthalmic medical assistants, ophthalmic nurses, and medical students
• Primary health care approach to extend coverage
• Faculty development at medical colleges

C. Infrastructure and Appropriate Technology Development

• Provision of adequate eye beds and surgical facilities
• Local production of eye medicines
• Refraction capability with spectacles and low vision devices
• Required surgical instrumentation (including low-cost IOLs)
• Sustainability built into technology use

6. Guiding Principles - ISEE

• I - Integration of eye care into health systems
• S - Sustainability
• E - Equity (community participation, equity of treatment and standard quality services)
• E - Evidence-based practice

7. India's Plan of Action under Vision 2020

National Programme for Control of Blindness (NPCB)

• 66 lakh cataract operations per year
• School eye screening + 9 lakh free spectacles per year for children with refractive errors
• Collection of 50,000 donated eyes per year for keratoplasty

8. Global Eye Health Action Plan 2014-2019

• Aimed to reduce avoidable visual impairment by 25% by 2019 from the 2010 baseline
• Was built on five principles: universal access and equity, human rights, evidence-based practice, life-course approach, and empowerment of the visually impaired
• Used the health systems approach - integrating eye care at primary, secondary, and tertiary levels
• Tracked progress using 3 national-level indicators:
  1. Prevalence and causes of visual impairment
  2. Number of eye care personnel
  3. Cataract surgical rate

9. After 2020 - "2030 in Sight"

• Setting the target that by 2030, no one should experience unnecessary sight loss
• Eye care and rehabilitation services should be accessible, inclusive, and affordable to everyone
• Emphasizing that national governments must own the process, with eye health as an integral part of universal health coverage

Summary Table