Exposure to Lead and Coronary Artery Atherosclerosis: A Swedish Cross-Sectional Population-Based Study

Background: Lead is an established causal risk factor for coronary heart disease. Atherosclerosis may be the key mediator for this association, but evidence from studies in humans is limited. Our objective was to test the hypothesis that environmental lead exposure is associated with coronary atherosclerosis. Methods: We used cross-sectional data from the SCAPIS (Swedish Cardiopulmonary Bioimage Study), including 5627 men and women aged 50 to 64 years. Coronary artery calcium score (CACS), measured using computed tomography, was used as a marker of atherosclerosis, and blood lead was used as a biomarker of lead exposure. The prevalence ratio (PR) of positive (>0) and high (>= 100) CACSs in relation to blood lead (continuous variable) was modeled using Poisson regression with robust SEs, adjusted for age, sex, smoking, low-density lipoprotein/high-density lipoprotein ratio, waist circumference, heredity for cardiovascular diseases, statin use, diabetes, blood cadmium, low physical activity, and educational level. Results: Median blood lead was 14.2 mu g/L. Positive CACS (prevalence, 41%) was not significantly associated with blood lead (PR per Delta 10 mu g/L, 1.02 [95% CI, 0.99-1.04]), whereas the association was stronger for high CACS (prevalence, 13%; and PR per Delta 10 mu g/L, 1.05 [95% CI, 1.00-1.11]). The estimate for high CACS was stronger in men (PR per Delta 10 mu g/L, 1.07 [95% CI, 1.01-1.13]) than among women (PR per Delta 10 mu g/L, 1.01 [95% CI, 0.85-1.20]). Conclusions: Our study, which found that lead is associated with coronary artery calcification in men, provides further evidence that lead is a risk factor for atherosclerosis and coronary heart disease.