The prevalence of symptomatic chronic bronchitis in two iron ore processing plants

Ryan, Mary Catherine (1983) The prevalence of symptomatic chronic bronchitis in two iron ore processing plants. Masters thesis, Memorial University of Newfoundland.

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Abstract

This research was undertaken to study the prevalence of symptomatic chronic bronchitis in a group of mining and mill workers to determine if there was an association between symptomatic chronic bronchitis and tobacco smoking, length of dust exposure or age, individually or synergistically. -- Analyses were done by two statistical methods. First, bivariate analysis done by cross tabulations using Chi-square as a test of significance gave the following results. -- (a) There was a significant association between tobacco smoking and symptomatic chronic-bronchitis. This association held when controlled by age and length of dust exposure. -- (b) Age was not significantly associated to symptomatic chronic bronchitis. -- (c) Length of dust exposure was not significantly associated to symptomatic chronic bronchitis. -- Second, a log-linear analysis was used to test different models for associations among the variables. The results confirmed the association between symptomatic chronic bronchitis and smoking, and showed that there were some interactive effects between the independent variables, smoking, age and length of exposure which may be explained by the correlation between age and length of exposure and by some differences in smoking habits by age.

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