Purpose: Markers of mercury (Hg) exposure have shown both positive and negative associations with cardiovascular disease (CVD). We assessed the association between serum Hg (S-Hg) and risk of cardiovascular disease in a prospective population-based cohort, with attention to the roles of dental health and fish consumption.
Methods: Total mortality, as well as morbidity and mortality from acute myocardial infarction (AMI) and stroke, was followed up for 32 years in 1,391 women (initially age 38-60), in relation to S-Hg at baseline, using Cox regression models. Potential confounders (age, socioeconomic status, serum lipids, alcohol consumption, dental health, smoking, hypertension, waist-hip ratio, and diabetes) and other covariates (e.g., fish consumption) were also considered.
Results: Hazard ratios (HR) adjusted only for age showed strong inverse associations between baseline S-Hg and total mortality [highest quartile: hazard ratio (HR) 0.76; 95% confidence interval (CI) 0.59-0.97], incident AMI (HR 0.56; CI 0.34-0.93), and fatal AMI (HR 0.31; CI 0.15-0.66). Adjustment for potential confounding factors, especially dental health, had a strong impact on the risk estimates, and after adjustment, only the reduced risk of fatal AMI remained statistically significant.
Conclusions: There was a strong inverse association between Hg exposure and CVD. Likely, reasons are confounding with good dental health (also correlated with the number of amalgam fillings in these age groups) and/or fish consumption. The results suggest potential effects of dental health and/or fish consumption on CVD that deserve attention in preventive medicine.