Farming activities and respiratory health in school age children

Abstract

There is limited study of the relationship between current farming exposures and childhood asthma, respiratory symptoms, and lung function. This thesis examined the prevalence of asthma in children living on and off farms and the risk of asthma and respiratory symptoms of children exposed to farming activities as well as the relationship between participation in selected farm related activities and lung function values in school age children.The analysis for this thesis was based on data collected from a cross-sectional study conducted in 2004 of 636 children ages 6-13 from an agricultural community in rural Saskatchewan. Parents on behalf of children completed a questionnaire of respiratory health and environmental exposures. Asthma was defined as doctor diagnosis of asthma. Respiratory symptoms were determined by report of cough, wheeze, phlegm. Individual farming activities assessed were; haying, harvesting, moving or playing with hay bales, feeding livestock, cleaning or playing in barns, cleaning pens, and emptying or filling grain bins. The health assessment, conducted at the schools with children, included measurements of height, weight, skin prick test for atopy and lung function (FEV1, FVC, FEV 25-75, FEV1/FVC ratio).There were 553 subjects with questionnaire data for a response rate of 86.9%. Of those subjects participating in the study, lung function was available for 532 subjects. The overall prevalence of asthma was 18.8% and the prevalence of respiratory symptoms was 39.8%. The prevalence of asthma or respiratory symptoms did not differ between children who lived on farms or in towns. After adjusting for significant or clinically important risk factors, children who were exposed to emptying and filling of grain bins were more likely to have asthma (OR=2.42, 95%CI:1.19-4.92). Children with respiratory symptoms were more likely to be exposed to haying activities (OR=1.92, 95% CI:1.03-3.56), playing on or near hay bales (OR=1.93, 95%CI:1.2 -2.96) or cleaning pens (OR=2.55, 95% CI:1.04-6.26). Lung function variables were not associated with participation in any of the seven farming activities tested.Although there were no differences in the prevalence of asthma and respiratory symptoms between farming and non-farming children, certain farming practices may be important in the etiology of asthma and related respiratory symptoms in children.