Lower blood pressure linked to reduced blood lead levels

Through the Strong Heart Family Study, researchers supported by the National Institutes of Health discovered that modest decreases in blood lead levels were linked to long-term cardiovascular improvements in American Indian adults. Participants experiencing the most significant reductions in blood lead levels saw a corresponding decrease of approximately 7 mm Hg in systolic blood pressure, a reduction akin to the impact of blood pressure-lowering medications.

The study’s results, reported by researchers from Columbia University Mailman School of Public Health, NIEHS, and NHLBI, are now published in the Journal of the American Heart Association.

Anne E. Nigra, PhD, an assistant professor of environmental health sciences at Columbia Mailman School of Public Health, and her co-authors, including Wil Lieberman-Cribbin, MPH, also at Columbia Mailman School, attribute these positive changes largely to public health and policy advancements occurring over the past few decades.

Beyond the improvements in systolic blood pressure, the investigators noted that decreases in blood lead levels were correlated with reductions in a marker associated with hypertrophic cardiomyopathy and heart failure.

To conduct the research, investigators collaborated with 285 American Indian adults through an extension of the Strong Heart Study, the most extensive study monitoring cardiovascular health outcomes and risk factors among American Indian adults. Participants were from four tribal communities in Arizona, Oklahoma, North Dakota, or South Dakota.

The researchers examined blood lead levels and blood pressure readings over time. Initial lead measurements were taken during the 1997-1999 study visit, with follow-up measurements collected between 2006-2009. During this period, participants had their blood pressure monitored and underwent medical examinations, including echocardiographs to evaluate their heart’s structure and function. To ensure consistent comparisons among participants, researchers controlled for various factors, including social variables, cardiovascular disease risks, and medical history.

At the study’s onset, the average blood lead level was 2.04 µg/dL. Over the course of the study, the average blood lead level decreased by 0.67 µg/dL, equating to a 33 percent reduction. The most noteworthy changes were observed in participants with average starting blood lead levels of 3.21 µg/dL, experiencing reductions of about 1.78 µg/dL (55 percent), which were linked to a 7 mm Hg reduction in systolic blood pressure.

The reductions in blood lead levels observed in the study mirror those seen in the general U.S. population over the past 50 years, following policies and initiatives aimed at minimizing lead exposure through measures such as regulating paint, gasoline, water, plumbing, and canned items.

The researchers emphasize the importance of further exploring these findings in different communities and seeking additional ways to minimize lead exposure, particularly in populations with heightened risks of exposure and cardiovascular disease.