A survey of chronic bronchitis among brassware workers

A stratified random sample of 580 workers aged between 18 and 50 years representing each sub-occupation in the brassware industry was studied for the prevalence of chronic bronchitis in relation to occupational and environmental factors. The findings were compared with those obtained in a reference group (N = 131) belonging to similar socio-economic status and unexposed to a dusty environment. Although the exposed group showed higher prevalence of chronic bronchitis in comparison to that observed in the controls (10.5 vs 5.3%), the difference was not significant at the 5% level. It was observed that the workers engaged in non-dusty occupations such as brass sheet cutting and engraving showed the lowest prevalence of the disease (5.0%) while those engaged in the dusty occupations viz., casting, soldering, electroplating and polishing showed the highest prevalence (12.0%). The smoking adjusted odds ratios calculated in various sub-occupations showed the highest risk of developing chronic bronchitis among the polishers (2.74). Though the risk in other occupational sub-groups was double, it did not attain a level of significance. The smoking adjusted odds ratios in relation to length of exposure showed that the risk was significantly higher among the workers exposed for over 10 years compared to those who worked for less than 10 years in the grinding, soldering and brass ingot making operations. The study thus showed a dose-response relationship between length of exposure and chronic bronchitis while effect of age on the disease was not discernible probably due to the small number of cases and the young age of the study group. The concentration of various metals in the air samples drawn from the work environment where main processes were in operation, was low compared to the prescribed level by ACGIH.