Farm-related factors associated with asthma in U.S. farm operators: Results from the 2006 Farm and Ranch Safety Survey

To develop national prevalence estimates for farm-related factors and explore their associations with current asthma, work-related asthma (WRA), and farm work-related asthma attacks in U.S. primary farm operators. In 2006, the National Agricultural Statistics Service conducted a regionally stratified telephone survey of 25,000 farm operations to address the health and safety concerns of primary farm operators. Self-reported data on 12,278 active farm operators were analyzed. National prevalences and adjusted prevalence odds ratios (PORs) were estimated using survey procedures in SAS^®. Of the estimated 2.1 million U.S. farms, approximately 51% were livestock and 46% were crop operations. The median age of operators was 57 years; 88% were males. Approximately 5% operators reported current asthma. Among these, 25% reported WRA and 28% reported work-related asthma attacks. Operators with current asthma were more likely to report exposure to moldy dust (POR=1.3) than those without asthma. Those with WRA were more likely to report exposures to diesel tractors (POR=3.1) and welding (POR=3.0). Among operators with current asthma, work-related asthma attacks were significantly associated with exposure to storage bags (POR=3.0), equine (POR=2.3), and moldy dust (POR=2.2); among livestock operators with current asthma, reporting exposure to equine (POR=3.4) and moldy dust (POR=3.0) were significant factors for work-related asthma attacks. These findings contribute to the limited information about associations between farm-related factors and asthma among primary farm operators, and can assist in establishing priorities for asthma prevention programs or targeting asthma intervention strategies on farms.