Circulating Serum Copper Is Associated with Atherosclerotic Cardiovascular Disease, but Not Venous Thromboembolism: A Prospective Cohort Study

<b><i>Background and Objective:</i></b> Serum copper has been linked to the risk of atherosclerotic cardiovascular disease (CVD). However, the potential association between serum copper and venous thromboembolism (VTE) is not known. The principal aim was to evaluate the potential prospective association between serum copper and VTE risk. A secondary aim was to confirm or refute previously reported associations between serum copper and atherosclerotic CVD. <b><i>Methods:</i></b> Serum copper was measured at baseline using atomic absorption spectrometry in 2,492 men aged 42–61 years without a history of VTE in the Kuopio Ischemic Heart Disease prospective cohort study. Cox regression models were used to calculate hazard ratios (HRs) with 95% confidence interval (CI) for VTE. <b><i>Results:</i></b> During a median follow-up of 27.0 years, 166 VTE events occurred. The risk of VTE per 1 standard deviation increase in serum copper in age-adjusted analysis was HR: 1.02; 95% CI: 0.88–1.20, which was attenuated to HR: 0.99; 95% CI: 0.82–1.19, following further adjustment for several established and emerging risk factors. Comparing the top versus bottom tertiles of serum copper, the corresponding adjusted HRs were 1.16 (95% CI: 0.80–1.66) and 1.11 (95% CI: 0.74–1.68), respectively. In 1,901 men without a history of coronary heart disease (CHD), the multivariable-adjusted HR for CHD was 1.32 (95% CI: 1.10–1.59) comparing extreme tertiles of serum copper. <b><i>Conclusion:</i></b> In middle-aged Finnish men, we confirmed previously reported associations between high serum copper levels and increased risk of atherosclerotic CVD, but serum copper was not associated with future VTE risk. Other large-scale prospective studies conducted in women, other age-groups, and other populations are needed to confirm or refute these findings.