Combined effect of cigarette smoking and non-ferrous metal exposure in the development of cardiovascular disease in industry workers: a case-control study

Materials and methods A retrospective case-control study was performed. Industry workers from a nonferrous plant and controls were monitored for an 8-year period. During this period, all workers received regular clinical examinations, which included evaluation for smoking status, occupational exposure to noxious non-ferrous metals (lead, Pb; cadmium, Cd), and cardiovascular disease (hypertension, coronary artery disease, peripheral vascular disease) using an epidemiological questionnaire . Four representative groups were selected: Group (1) included all workers with both smoking and exposure to noxious non-ferrous metals. Group (2) included workers with smoking but without noxious metal exposure. Group (3) included workers without smoking but with exposure to noxious metals. Group (4) included workers without smoking and without exposure to noxious metals. Groups (2) and (4) were selected in such a way to match Groups (1) and (3) by age, gender, work history, and lifestyle. The prevalence of smoking and cardiovascular disease 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 cardiovascular disease.