Background: There are few population-based studies addressing hypersensitivity pneumonitis (HP) in the United States. The National Institute for Occupational Safety and Health (NIOSH) has nationally comprehensive longitudinal mortality data that can contribute to a better understanding of the epidemiology of HP.
Methods: The National Center for Health Statistics multiple cause-of-death data were analyzed for the period 1980-2002. Annual death rate was age-adjusted to the 2000 U.S. standard population. Death rate time-trends were calculated using a linear regression model and geographic distribution of death rates were mapped by state and county. Proportionate mortality ratios (PMRs) by usual industry and occupation adjusted for age, sex, and race, were based on data from 26 states reporting industry and occupation during 1985-1999.
Results: Overall age-adjusted death rates increased significantly (P < 0.0001) between 1980 and 2002, from 0.09 to 0.29 per million. Wisconsin had the highest rate at 1.04 per million. Among industries, PMR for HP was significantly high for agricultural production, livestock (PMR, 19.3; 95% CI, 14.0-25.9) and agricultural production, crops (PMR, 4.3; 95% CI, 3.0-6.0). Among occupations, PMR for HP was significantly elevated for farmers, except horticulture (PMR, 8.1; 95% CI, 6.4-10.2).
Conclusions: These findings indicate that agricultural industries are closely associated with HP mortality and preventive strategies are needed to protect workers in these industries.