Serum levels of lead, mercury and cadmium in relation to coronary artery disease in the elderly: A cross-sectional study

Abstract

Background: There is a continuing attempt to identify novel factors that can predict the risk of cardiovascular disease beyond the established coronary risk factors. It has been suggested that serum levels of lead, mercury and cadmium are associated with the risk of coronary artery disease (CAD). In the present study, we aimed to evaluate serum concentrations of lead (s-Pb), mercury (s-Hg) and cadmium (s-Cd) in patients with CAD in comparison with those of healthy individuals. The correlation between serum levels of these heavy metals and lipid profile parameters was also investigated.

Methods: In this case-control study, we included 65 patients (35 females) aged 50-70 years with angiographically-documented CAD and 65 healthy controls (43 female) matched for sex, age and place of residence. Serum concentrations of heavy metals were determined using graphite furnace atomic absorption (GFAA). Serum lipids were measured using routine enzymatic methods.

Results: It was observed that the mean concentration of s-Pb (12.54 ± 8.41 vs. 5.89 ± 4.44 μg/L, p < 0.05) and s-Cd (0.938 ± 0.72 vs. 0.448 ± 0.30, p < 0.05; CI: 95%) and s-Hg (10.14 ± 5.06 vs. 6.11 ± 5.66, p < 0.05) were significantly higher in CAD patients compared with control subjects. The same result was also obtained after adjustment for cardiovascular risk factors including age, dyslipidemia, diabetes mellitus and hypertension (p < 0.05). The mean concentration of total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C) and TC:HDL-C ratio were significantly higher in CAD patients (p < 0.05). There was no significant association between serum metal concentrations with TC, HDL-C and TC:HDL-C ratio (p > 0.05).

Conclusions: The present results showed that serum levels of heavy metals are associated with the presence of CAD. Long-term exposure to trace levels of Pb, Cd and Hg may play a role in the development of coronary atherosclerotic plaques.

Keywords: Cadmium; Coronary artery disease; Heavy metals; Lead; Mercury.