Airborne Metal Exposure and Risk of Hypertension in the Sister Study

Abstract

Background Hypertension-related disease burden is a major challenge globally, and an estimated 1.56 billion adults will be affected by hypertension by 2025. Environmental factors, such as metals, could be risk factors for hypertension. However, the relationship between airborne metals and hypertension is rarely studied. Methods 49,876 women in the Sister Study cohort were included in this study. Census-tract airborne metal concentrations (arsenic, cadmium, chromium, cobalt, lead, manganese, mercury, nickel, selenium, and antimony) from the 2005 National Air Toxics Assessment database were linked to participants’ enrollment residential address. Hypertension was defined as high systolic (≥140) or diastolic (≥90) blood pressure (measured by trained examiners at enrollment) or taking anti-hypertensive medication. Logistic regression was used to estimate adjusted odds ratios (ORs) and 95% confidence intervals (CIs) for the association between individual metals and hypertension, with and without co-adjustment for other metals. Quantile-based g-computation was used to estimate the joint effect of the overall metal mixture. Results Risk of hypertension was higher among women of higher exposure to arsenic (OR quartile 4 vs 1=1.11, 95%CI=1.05,1.18), lead (OR quartile 4 vs 1=1.11, 95%CI=1.04,1.17), chromium (OR quartile 4 vs 1=1.07, 95%CI=1.01,1.14), cobalt (OR quartile 4 vs 1=1.07, 95%CI=1.01,1.14), and manganese (OR quartile 4 vs 1=1.07, 95%CI=1.01,1.13). Selenium was associated with lower risk of hypertension (OR quartile 4 vs 1=0.92, 95%CI=0.87,0.98). Results were similar with mutual adjustment for other metals. Race modified the associations, with greater ORs in non-white participants compared with non-Hispanic white participants. The joint effect of increasing all ten metals by one quartile was 1.04 (95%CI=0.98,1.10). Conclusion We found that living in areas of higher exposure to arsenic, lead, chromium, cobalt, and manganese was related to higher risk of hypertension, whereas exposure to selenium was inversely related to the risk of hypertension.