California's generally arid climate and land cultivation practices combine to generate agricultural dusts which present challenges to the respiratory health of farmers. 620 (72%) of current UC Davis Fanner Health Study cohort members who were still working in 2004, were questioned about symptoms of asthma, persistent wheeze, chronic cough and bronchitis using a CATI. Exposures to a range of animal and crop tending tasks, previously associated with dust generation, were recorded in four ways; ever performed, number of years, performed last year, and number of days. From Chi-sq analyses, significant associations (p< 0.05) between incident symptoms and exposures were assessed in multivariable logistic regression models adjusted for age and smoking status. Mean age of farmers was 62.4 (sd 11.6) years, range 36-94. 124 fanners reported current respirator symptoms, who were symptom free in 1993 (when first contacted); 94 of these reported one, 20 reported two and 10 reported three symptoms. 7.7% (48) were evaluated to have incident persistent wheeze, 6.8% (42) with chronic bronchitis, 6.6% (41) with chronic cough, and 5.3% (33) with asthma. New CC was associated with last year dust intensity, OR = 1.19 (95%CI 1.05-1.35) and with time working in dust OR = 1.02 (95 1.003-1.028). More specifically, new PW was significantly associated with years performing mechanical harvesting and number of days last year driving a tractor. Incident asthma was associated with days hand harvesting last year, CB with any hand harvesting last year, and CC with number of days performing maintenance shop work. In this population of older working farmers, incident respiratory symptoms were associated with tasks which generated agricultural dusts, including tractor driving, mechanical and hand harvesting and general shop/repair work.
Proceedings of the American Thoracic Society. 2005 ATS International Conference, May 20-25, 2005, San Diego, California