Blood Cadmium Levels and Incident Cardiovascular Events during Follow-up in a Population-Based Cohort of Swedish Adults: The Malmö Diet and Cancer Study

Abstract

Background: Cadmium exposure may increase the risk of cardiovascular disease. The only published longitudinal study on cadmium and incident cardiovascular disease was performed in American Indians with relatively high cadmium exposure.

Objectives: Our aim was to examine the association between blood cadmium at baseline and incident cardiovascular events in a population-based study of Swedish men and women with cadmium levels similar to those of most European and U.S.

Methods: A Swedish population-based cohort (n = 6,103, age 46-67 years) was recruited between 1991 and 1994. After we excluded those with missing data on smoking, 4,819 participants remained. Acute coronary events, other major cardiac events, stroke, and cardiovascular mortality were followed until 2010. Associations with blood cadmium (estimated from cadmium in erythrocytes) were analyzed using Cox proportional hazards regression including potential confounders and important cardiovascular risk factors.

Results: Hazard ratios for all cardiovascular end points were consistently increased for participants in the 4th blood cadmium quartile (median, 0.99 μg/L). In models that also included sex, smoking, waist circumference, education, physical activity, alcohol intake, serum triglycerides, HbA1c, and C-reactive protein, the hazard ratios comparing the highest and lowest quartiles of exposure were 1.8 (95% CI: 1.2, 2.7) for acute coronary events, and 1.9 (1.3, 2.9) for stroke. Hazard ratios in never-smokers were consistent with these estimates.

Conclusions: Blood cadmium in the highest quartile was associated with incident cardiovascular disease and mortality in our population-based samples of Swedish adults. The consistent results among never-smokers are important because smoking is a strong confounder. Our findings suggest that measures to reduce cadmium exposures are warranted, even in populations without unusual sources of exposure.

Citation: Barregard L, Sallsten G, Fagerberg B, Borné Y, Persson M, Hedblad B, Engström G. 2016. Blood cadmium levels and incident cardiovascular events during follow-up in a population-based cohort of Swedish adults: the Malmö Diet and Cancer Study. Environ Health Perspect 124:594-600; http://dx.doi.org/10.1289/ehp.1509735.

Figure 1

Hazard ratios and 95% confidence intervals for acute coronary event (ACE; acute myocardial infarction, or death in ischemic heart disease), major cardiac events (ACE, or coronary artery by-pass graft, or percutaneous coronary intervention), stroke, and cardiovascular mortality by quartiles of cadmium concentration in blood (white: quartile 1; blue: quartile 2; gray: quartile 3; black: quartile 4). The models were adjusted for age (time scale), sex, smoking, waist circumference, low education, low physical activity, alcohol intake, serum triglycerides, HbA1c, and C-reactive protein. For other models, see Table 2.