Abstract
Respiratory disease is a common chronic illness among farmers and can interfere with many aspects of daily living. Agricultural practices and exposures vary with geographic region, and there are few data on western, dry climate farmers. These results are based on a longitudinal study of a representative cohort of California farmers that began in 1993. In 1998, 1,349 operators completed a telephone interview assessing relevant health outcomes, occupational hazards, and functional status. 90% of those interviewed were male with an average age of 54 years. There was a low prevalence of smoking in this cohort with 10.8% current, 38.2% ex- and 50.9% non-smokers. New cases of cough were recorded in 5.9% of the cohort, 7% of the cohort for bronchitis and 8.2% of the cohort for persistent wheeze. Symptoms disappeared between 1993 and 1998 for over one-third of participants (37%, 39% and 50% for cough, bronchitis and persistent wheeze, respectively). Farming tasks that bring on wheezing or make it worse reported by farmers include handling of straw/hay (23%), loading/stacking bales (20%), feeding of hay (19%), mechanical mowing of weeds (17%), and mechanical harvesting (14%). Multivariate models adjusted for age, sex and smoking status found increased odds of incident chronic bronchitis among farmers involved in residue burning (OR=I.5, 95% CI=[1.0,2.4]), feeding manufactured grains (OR=2.8, 95% CI=[1.4,5.5]), and handling hay/straw (OR=2.3, 95% CI=[1.3,4.1]). There were no associations between farm tasks and incident cases of cough or persistent wheeze. Agricultural practices and exposures in California are different from other parts of the country. Understanding specific determinants of chronic respiratory disease in California farmers is a critical component of health promotion and disease prevention recommendations in this population.