Environmental Exposure to Lead and Risk of Atherosclerosis

Abstract

Background: Lead exposure is associated with an increased risk of cardiovascular mortality. Atherosclerosis has been hypothesized to be one mechanism underlying this association. Aim: To assess whether lead exposure, assessed as the concentrations in blood, is associated with an increased risk of atherosclerosis in the carotid arteries in a large Swedish population-based cohort. Methods: We performed a cross-sectional study using data from the population-based Swedish CardioPulmonary bioImage Study (SCAPIS), including 5622 men and women (50-64 years of age), enrolled 2013-2018. Blood lead (B-Pb), measured by inductively coupled plasma mass spectrometry, was used as exposure biomarker (in quartiles). The presence of atherosclerotic plaque in the carotid arteries was determined by ultrasonography. Associations between B-Pb and the risk of plaque was analysed using Poisson regression to estimate prevalence ratios (PR) in models adjusted for age, sex, LDL/HDL ratio, diabetes mellitus, waist circumference and smoking status. Results: The prevalence of atherosclerotic plaques was 57% and the median B-Pb concentration was 14 μg/L (range: 0.75-203). Individuals in the fourth quartile of B-Pb (Q4) as compared with the first quartile (Q1), had a PR for plaque of 1.08 (95%CI: 1.01, 1.16), which was slightly higher among men (PR 1.11; 95%CI: 1.02, 1.20). PRs were weaker and non-significant among women (PR 1.06; 95%CI: 0.95, 1.17). Among never-smokers, associations were mostly non-significant, except for women in Q3 (PR 1.29; 95%CI: 1.09, 1.53). Conclusions: Individuals in the highest quartile of blood lead had a slightly increased risk of carotid plaque in this sample of the general population with lead concentrations comparable to those in other European countries and the U.S. Our study provides some support for the hypothesis that atherosclerosis is one of the mechanisms underlying the association between lead and cardiovascular disease.