Respiratory symptoms in Swiss farmers: An epidemiological study of risk factors

Background The study was undertaken to assess the prevalance and risk facto rs of self-reported asthma, symptoms of chronic bronchitis, hayfever, and w ork-related respiratory symptoms in Swiss farmers as well as to compare the prevalance rates of respiratory symptoms with the Swiss population (SAPALD IA-Study), Methods An epidemiological study was performed with a representative sample of 1,542 Swiss farmers using a self-administered questionnaire. To investi gate the effect of the type of farming on reported symptoms, the farmers we re subdivided into seven groups according to the rime farmers spent in diff erent animal confinement buildings. A multivariate analysis was performed b y the methods of binary and multivariate logistic regression adjusted for a ge and smoking habits. Results In farmers the prevalence rate was 16.0% for chronic bronchitis, 15 .4% for asthma symptoms, and 42.0% for reporting at least one work-related symptom. Using logistic regression analysis, it was established that poultr y fanning and pig/cattle farming was a risk factor for reporting nasal irri tation at work [OR 5.33, (1.57-18.0), OR 3.37 (1.04-10.87)]. Poultry farmer s experienced the highest symptom rates. In crop farmers, the prevalance fo r chronic bronchitis was increased [OR 2.32 (1.03-5.23)]. Over 4 hr spent p er day in animal confinement buildings more than doubled the risk for repor ting chronic bronchitis [OR 2.61 (1.01-6.76)] and phlegm COR 2.3 (0.99-5.4) independent of the type of fanning. The comparison of Swiss farmers with t he Swiss population showed a twofold elevated risk of reporting chronic bro nchitis [OR 1.89 (1.32-2.95)] and a 4.5-fold elevated risk for bringing up phlegm regularly [OR 4.5 (3.25-6.69)] in farmers. In contrast, the risk of farmers to report nasal allergies was less than half as high [OR 0.40 (0.29 -0.56)] as that of the general population. Conclusions This study shows that agricultural work in Switzerland is assoc iated with an elevated risk for reporting symptoms of chronic bronchitis an d chronic phlegm compared with the general Swiss population. These main res ults most likely indicate occupational disorders as the exposure-response r elationship (hours spen in animal confinements) was particularly obvious fo r these symptoms. (C) 2001 Wiley-Liss, Inc.