Blood Lead Levels and Risk of Deaths from Cardiovascular Disease

Abstract

Environmental exposure could be an important modifiable risk factor for cardiovascular disease (CVD). In this study, we investigated the relation between lead exposure, measured as blood lead levels (BLLs) and CVD mortality in a national cohort. A total of 15,036 adults aged ≥19 who participated in the National Health and Nutrition Examination Survey (1988 to 1994) as the baseline examination were followed up through December 31, 2010. Adjusted hazard ratios (HRs) derived from Cox proportional hazard regressions were used to estimate the risk of dying from CVD in association with BLLs. Cardiovascular mortality was 3.76, 8.11, and 14.77 per 1,000 person-years for patients in low, moderate, and high BLLs, respectively. After adjusting for potential confounders, patients in the high lead level had a significantly increased risk of death from all CVD (HR 1.35, 95% confidence interval 1.03 to 1.77), compared with those with low level. Participants in both moderate and high lead levels showed a significantly increased risk of death from heart disease, with an HR of 1.37 (1.04 to 1.81) and 1.60 (1.21 to 2.13), respectively. A significant linear association with all CVD and heart disease deaths was also seen with an HR of 1.08 (1.00 to 1.16) and 1.09 (1.02 to 1.16), respectively, per 1-unit increase in BLLs. In conclusion, the study demonstrates that increasing BLLs were associated with an increased risk of cardiovascular deaths, especially from heart disease. This further supports the possible cardiovascular effects that lead poses on patients at low levels of exposure and the importance of further reducing lead exposure in the general population.