Association between serum copper levels and stroke in the general population: A nationally representative study

Association of Blood Copper With the Subclinical Carotid Atherosclerosis: An Observational Study

BACKGROUND

Copper exposure is reported to be associated with increased risk of stroke. However, the association of copper exposure with subclinical carotid atherosclerosis remains unclear.

METHODS AND RESULTS

This observational study included consecutive participants from Xinqiao Hospital between May 2020 and August 2021. Blood metals were measured using inductively coupled plasma mass spectrometry and carotid atherosclerosis was assessed using ultrasound. Modified Poisson regression was performed to evaluate the associations of copper and other metals with subclinical carotid plaque presence. Blood metals were analyzed as categorical according to the quartiles. Multivariable models were adjusted for age, sex, body mass index, education, smoking, drinking, hypertension, diabetes, dyslipidemia, estimated glomerular filtration rate, and coronary artery disease history. Bayesian Kernel Machine Regression was conducted to evaluate the overall association of metal mixture with subclinical carotid plaque presence. One thousand five hundred eighty-five participants were finally enrolled in our study, and carotid plaque was found in 1091 subjects. After adjusting for potential confounders, metal-progressively-adjusted models showed that blood copper was positively associated with subclinical carotid plaque (relative risk according to comparing quartile 4 to quartile 1 was 1.124 [1.021-1.238], relative risk according to per interquartile increment was 1.039 [1.008-1.071]). Blood cadmium and lead were also significantly associated with subclinical carotid plaque. Bayesian Kernel Machine Regression analyses suggested a synergistic effect of copper-cadmium-lead mixture on subclinical carotid plaque presence.

CONCLUSIONS

Our findings identify copper as a novel risk factor of subclinical carotid atherosclerosis and show the potential synergistic proatherogenic effect of copper, cadmium, and lead mixture.

The Association between Serum Copper and Bone Mineral Density among Adolescents Aged 12 to 19 in the United States

Bone mineral density (BMD) is a key parameter widely used in the assessment of bone health. Although many investigations have explored the relationship between trace elements and BMD, there are fewer studies focused on serum copper and BMD, especially for adolescents. Using data extracted from the National Health and Nutrition Examination Survey, we applied a multiple-linear regression and smooth curve fitting to assess the relationship between serum copper and BMD. A total of 910 participants were finally included in this study. After adjusting for relevant covariates, serum copper was negatively associated with lumbar spine BMD (β = -0.057, 95% CI: -0.109 to -0.005), trunk bone BMD (β = -0.068, 95% CI: -0.110 to -0.026), pelvis BMD (β = -0.085, 95% CI: -0.145 to -0.024), subtotal BMD (β = -0.072, 95% CI: -0.111 to -0.033), and total BMD (β = -0.051, 95% CI: -0.087 to -0.016) (p < 0.05). In quartile analysis, the highest level of serum copper was associated with decreased BMD when compared with those at the lowest quartile (p < 0.05). The stratified analysis revealed a significant interaction between age and the effects of serum copper on trunk bone BMD (p = 0.022) and pelvis BMD (p = 0.018). Meanwhile, the higher level of serum copper was negatively associated with BMD in males, and gender modified the relationship (p < 0.001). Future longitudinal studies will be necessary for a more definitive interpretation of our results.