Low-level environmental lead and cadmium exposures and dyslipidemia in adults: Findings from the NHANES 2005–2016

Previous experimental and occupational health studies have shown the toxic effects of relatively high-level cadmium and lead on lipid metabolism. However, limited studies investigated the relationships between serum lipid levels and exposure to low-level lead and cadmium in adults. To investigate the associations between lead and cadmium levels in blood and dyslipidemia in adults. A retrospective cross-sectional study of 7,457 adults aged 20–79 years who were recruited in the National Health and Nutrition Examination Survey (NHANES, 2005–2016) was conducted. Multivariate linear and logistic regressions were used to examine the associations of blood lead and cadmium levels with serum lipid profiles and risk of dyslipidemia, respectively. The weighted geometric means [95% confidence intervals (CIs)] of lead and cadmium in blood were 1.23 (1.21, 1.25) μg/dL and 0.36 (0.35, 0.37) μg/L, respectively. Blood lead was significantly associated with serum total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), non-high-density lipoprotein cholesterol (non-HDL-C), and apolipoprotein B (Apo B) levels after adjusting for covariates. Compared with the adults in the lowest blood lead quartile (≤0.76 μg/dL), those in the highest lead quartile (>1.90 μg/dL) had higher risks of elevated TC (OR = 1.88, 95% CI: 1.59–2.22), non-HDL-C (OR = 1.59, 95% CI: 1.33–1.91), LDL-C (OR = 1.68, 95% CI: 1.41–1.99) and Apo B (OR = 2.00, 95% CI: 1.46–2.73). However, the single effect of cadmium exposure and the joint effect of lead and cadmium exposures on dyslipidemia were not observed. Blood lead well below the current recommended level was positively associated with the risk of dyslipidemia in adults, while the low-level cadmium exposure currently observed in adults did not show any significant associations with lipid levels.