Urinary Heavy Metals and Longitudinal Changes in Blood Pressure in Midlife Women: The Study of Women’s Health Across the Nation

Environmental exposure to heavy metals may contribute to increased blood pressure; however, evidence from midlife women who are at greater risk of cardio-metabolic disease is limited. We evaluated the associations of urinary concentrations of arsenic, cadmium, mercury, and lead with longitudinal changes in blood pressure in the Study of Women’s Health Across the Nation Multi-Pollutant Study. The sample included 1317 White, Black, Chinese, and Japanese women, aged 45 to 56 years at baseline (1999–2000), whose systolic blood pressure (SBP) and diastolic blood pressure were measured annually or biannually through 2017. Urinary metal concentrations were determined at baseline. Longitudinal changes in SBP and diastolic blood pressure were modeled using linear mixed-effects models by tertiles of metal concentrations. After multivariable adjustment, estimated annualized increases (95% CI) in SBP in the highest and lowest tertiles were 0.93 (0.85–1.01) mm Hg and 0.74 (0.66–0.82) mm Hg for arsenic, 0.82 (0.75–0.90) mm Hg and 0.72 (0.65–0.80) mm Hg for mercury, and 0.86 (0.78–0.93) mm Hg and 0.72 (0.64–0.79) mm Hg for lead, respectively. Similar results were observed for associations of arsenic, mercury, lead with diastolic blood pressure. Urinary cadmium was associated with a greater rate of increase in SBP only among never smokers. Women with higher concentrations of all four metals had greater annualized increases in SBP and diastolic blood pressure than those with lower concentrations. Our findings suggest that exposure to heavy metals may accelerate the increase in blood pressure in midlife women, supporting the need for continued efforts to reduce these environmental exposures.