PREDICTORS OF ASTHMA AND WHEEZING IN ADULTS - GRAIN FARMING, SEX, ANDSMOKING

We investigated predictors for asthma and wheeze in 1,634 men and wome n in the age group 20 to 65 yr from the town of Humboldt, Saskatchewan . On the basis of questionnaire responses, subjects were classified in to mutually exclusive groups as asthmatic (n = 62), wheezing (n = 444) , asymptomatic (n = 908), and symptomatic (n = 220) groups. After excl uding the symptomatic group, we used polytomous logistic regression mo dels to determine predictors of asthma and wheezing. Significant predi ctors for asthma were grain farming (odds ratio [OR] = 1.9, 95% confid ence interval [Cl]: 1.1-3.5; p = 0.03) and sex (OR = 1.9, Cl: 1.1-3.2; p = 0.03; males compared with females). Significant predictors for wh eezing were smoking (former smoker: OR = 1.8, Cl: 1.3-2.5, p < 0.001; current smoker: OR = 5.0, Cl: 3.8-6.7, p < 0.001; in comparison to non smoker) and grain farming (OR = 1.7, Cl: 1.3-2.4, p < 0.001). Age, lev el of education, and physical activity at work were not significant pr edictors for asthma or wheezing. None of the interaction effects betwe en the predictors was significant. When stratified by sex, grain farmi ng was a significant predictor of asthma in men but not in women. Neve rtheless, smoking and grain farming were significant predictors of whe ezing in both men and women. Our study raises the possibility that gra in farming might be a risk factor for asthma and asthma-like symptoms.