A cross-sectional study of pulmonary function among workers exposed to multimetals in the glass bangle industry

Spirometric lung functions were evaluated in 220 asymptomatic glass bangle workers exposed to the salts of various heavy metals, such as arsenic, lead, zinc, copper, manganese, cobalt, cadmium, and selenium, which are used as coloring agents in the manufacture of glass bangles. The mean values of various spirometric variables (viz. FVC, FEV1, IMBC, and PEFR) were within normal range (more than 80% of the predicted values) in both smoking and nonsmoking glass bangle workers and did not reveal any significant differences in comparison with those observed in the unexposed controls. However, variables such as FEV1/FVC% ratio, FEF25-75 and FEF75-85 were reduced significantly (p less than 0.001) in the exposed group. The reduction was more marked in the smoking glass bangle workers indicating additive effect of cigarette smoking on the small airways. The exposed group showed a significantly higher prevalence (16.3%) of respiratory impairment in comparison to that observed in the controls (7.9%) as a result of exposure to various metals in the work environment (p less than 0.01). The respiratory impairment observed in the exposed group indicated primarily restrictive pattern of pulmonary abnormality (10.4%), while the controls revealed only 1.1% prevalence of this disease (p less than 0.001). The effect of the duration of exposure on the prevalence of respiratory impairment in the glass bangle industry revealed significantly higher prevalence (p less than 0.05) in those who worked for more than 10 years (23.0%) than in those who worked for less than 10 years (10.8%) thereby indicating that the duration of exposure is directly related to the prevalence of respiratory impairment.