Epidemiology of Chronic Otitis Media (Mucosal Type / CSOM) - Nepal and Global

Global burden

• CSOM is estimated to affect around 250-330 million people worldwide, with roughly 60% (about 200 million) suffering some degree of hearing impairment as a result.
• WHO classifies CSOM prevalence bands: <1% = low, 1-4% = high, >4% = very high burden. Populations with the highest rates (often >4%) include Indigenous Australians, Alaskan and Canadian Inuit, Greenlandic Inuit, and some Pacific Island and Sub-Saharan African populations.
• By WHO region, the South-East Asia and Western Pacific regions contribute roughly 85-90% of the global CSOM burden, with India and China accounting for much of this - India due to high prevalence rate, China due to sheer population size.
• A 2025 systematic review (Onifade et al., J Epidemiol Glob Health) pooling studies from 18-19 countries (2005-2023) found CSOM prevalence data most commonly from India, Nepal, South Korea, and Bangladesh, and suggested the South-East Asia region may have even greater prevalence than Africa or the Western Pacific.
• Global Burden of Disease 2021 data show otitis media cases (all types) rose from about 322 million (1992) to 391 million (2021) globally, with a stable/rising incidence but a declining age-standardized prevalence and DALY rate overall - though low and low-middle SDI (socioeconomic development index) regions continue to bear a disproportionate burden.
• Children under 5 account for a substantial share of cases (roughly 22% of global CSOM incidence), and CSOM disproportionately affects socioeconomically disadvantaged populations, with risk factors including malnutrition, overcrowding, poor hygiene/water access, upper respiratory infections, and limited healthcare access.
• CSOM can progress to serious complications (mastoiditis, intracranial abscess, meningitis) in a minority of cases, and is linked to worse quality of life, and in some populations, higher rates of depression and anxiety.

Nepal-specific data

• A study from urban private school children in Nepal (Adhikari et al., 2009, Braz J Otorhinolaryngol) found significant CSOM burden among schoolchildren.
• A more recent Nepali study (eastern Nepal, general population/community screening) reported a CSOM prevalence of 8.2%, with the majority of cases occurring in the 11-15 year age group (51.9%) - indicating school-age children are disproportionately affected.
• A separate study among Tibetan populations in Nepal also documented high CSOM rates, consistent with the broader pattern of elevated CSOM burden in Indigenous/high-altitude and disadvantaged populations.
• Nepali patients with CSOM have been shown to report lower quality of life compared with healthy controls, and quality of life improves after corrective (tympanoplasty/mastoid) surgery.
• Overall, Nepal's rates (roughly 5-8%+ in various community and school-based surveys) place it well above the WHO "high burden" threshold of 4%, reflecting the country's socioeconomic risk factor profile - poor access to ENT care in rural/hill areas, crowding, malnutrition, and high rates of untreated acute otitis media progressing to chronic disease.

Key takeaway

Epidemiology of COM (Mucosal Type) - Key Points for Case Study

• Affects ~250-330 million people worldwide; ~60% (~200 million) have associated hearing impairment.
• WHO burden classification: <1% low, 1-4% high, >4% very high prevalence.
• South-East Asia and Western Pacific regions account for ~85-90% of global CSOM burden (India, China contribute most).
• Disproportionately affects LMICs and disadvantaged/Indigenous populations (highest rates in Aboriginal Australians, Inuit populations, some African and Pacific groups).
• Children under 5 make up ~22% of global incidence.

• Falls in the WHO "high/very high burden" category.
• Community-based study (eastern Nepal): prevalence 8.2%, majority in the 11-15 year age group (51.9%).
• School-based Nepal study also confirmed significant CSOM burden among children.
• Risk factors: poor access to ENT care (especially hill/rural areas), overcrowding, malnutrition, untreated acute otitis media.
• Associated with reduced quality of life, improving after tympanoplasty/mastoid surgery.

• Global: ~250-330 million affected; ~60% have hearing impairment. High burden in South-East Asia/Western Pacific (India, China).
• Nepal: Prevalence ~8.2%, mostly in 11-15 year age group. Classified as "high burden" (>4%, WHO).