Hypersensitivity pneumonitis epidemiology and demographics

Overview
Hypersensitivity pneumonitis usually occurs in people who work in places where there are high levels of organic dusts, fungus, or molds. As the causative agent is dust, the prevalence of HP varies significantly by region, climate, occupation/exposure and farming practices.

Prevalence by occupation

 * Farmers:
 * US: 8-540 cases per 100,000 persons per year among those at risk
 * UK: 420-3000 cases per 100,000 persons per year among those at risk
 * France: 4370 cases per 100,000 persons per year among those at risk
 * Finland: 1400-1700 cases per 100,000 persons per year among those at risk


 * Pigeon Breeders: 6000-21,000 cases per 100,000 persons per year


 * Bird Fanciers: 20-20,000 cases per 100,000 persons per year


 * Attack rates vary considerably, but can be high in sporadic outbreaks. For example a large proportion (52%) of office workers exposed to an infected humidifier were affected in one outbreak, and in another outbreak 27% of workers at a molding plant for polyurethane foam parts were affected.

Prevalence by gender
Males are slightly more affected, The male to female ratio being approximately 1.2:1.

Prevalence by age
It generally occurs in patient with fourth and fifth decade of there life. The mean age of the patients with HP is 61 ± 0.7 years.