Objectives Purpose of the study: (1) to determine the prevalence of digestive diseases in workers in non-ferrous metallurgy, and (2) to evaluate the effect of cigarette smoking in the development of digestive diseases in exposed workers.

Method A retrospective combined cross-sectional and case-control study was performed. Industry workers from a nonferrous plant and controls were monitored for an 8-year period. All workers received regular clinical examinations: evaluation for *smoking status, *occupational exposure to Pb and Cd, *digestive disease using an epidemiological survey. Four representative groups were selected: Group (1)-exposed smokers, Group (2)-non-exposed smokers, Group (3)-exposed non-smokers, Group (4)-non-exposed non-smokers. The prevalence of digestive diseases was determined in each group. Linear regression analysis was used to assess the correlation between the levels of exposure and biomarkers of exposures, as well as between the amount of smoking and the burden of digestive disease.

Results During the studied period, Pb&Cd levels in the air of all workplaces were persistently high (Pb = 0.9–13.3 mg/m³; Cd = 0.3–1.3 mg/m³). Clinical examination identified the classic symptoms of chronic occupational intoxication with Pb. There was a relatively high prevalence of smoking in group (1) and (2). The prevalence of digestive disease was significantly higher in exposed smokers. Linear regression analysis showed close relationship between the studied parameters.

Conclusions There is high prevalence of smoking and digestive disease in industry workers. Cigarette smoking may act as a confounder in the assessment of the severity of occupational disease related to noxious metal exposure in industry workers. The goal for all facilities and workers is to minimise smoking and occupational exposure to noxious agents.