Even low blood lead levels aggravate hypertension risk

Blood lead level correlates significantly with the risk of hypertension, even among people with low blood concentrations, a recent study has found.

Drawing from the US National Health and Nutrition Examination Survey 1999–2016, researchers looked at 39,447 adults with available blood lead and blood pressure measurements. Hypertension, if not already diagnosed or self-declared, was defined according to the 2017 guidelines of the American Heart Association/American College of Cardiology.

Of the participants, 20,803 were hypertensive (mean age, 54.08±0.23 years; 51.6 percent male) while 18,674 were not (mean age, 39.87±0.19; 44.6 percent male). Aside from age and sex, blood lead also differed significantly between subgroups, with the former registering significantly higher mean concentrations than the former (1.44 vs 1.22 µg/dL; p<0.001).

Increasing blood lead levels also resulted in changes in blood pressure and, in turn, hypertension risk. Every doubling of blood lead concentration correlated significantly with a 3.25-mm Hg (95 percent confidence interval [CI], 2.94–3.55) spike in systolic blood pressure, and 45-percent increase in hypertension risk (odds ratio [OR], 1.45, 95 percent CI, 1.40–1.50).

Dividing participants according to blood lead quartiles resulted in similar outcomes. Relative to those with concentrations <0.89 µg/dL, blood lead levels of 0.89 to <1.30 µg/dL (OR, 1.15, 95 percent CI, 1.04–1.26), 1.30 to <2.10 µg/dL (OR, 1.17, 95 percent CI, 1.05–1.31), and ≥2.10 µg/dL (OR, 1.21, 95 percent CI, 1.07–1.36) all significantly increased the risk of hypertension.

“Our findings suggest that reducing present levels of environmental lead exposure may benefit adults by reducing blood pressure and its attendant cardiovascular risk,” researchers said.