Researchers have linked a decade-long decline in the blood lead levels of American Indian adults to long-term cardiovascular health benefits, including reduced blood pressure levels and a reduction in a marker associated with hypertrophic cardiomyopathy and heart failure.
The research, supported by the National Institutes of Health, found that adults who had the greatest reductions in blood lead levels saw their systolic blood pressure fall by about 7 mm Hg, an amount comparable to the effects of blood pressure-lowering medication. Lead exposure is known to harm the health of children by damaging the brain and nervous system and slowing growth and development. It has also been associated with increased risks for heart disease in adults. The findings published in the Journal of the American Heart Association.
Investigators partnered with 285 American Indian adults in the Strong Heart Family Study, an extension of the Strong Heart Study. Participants lived in one of four tribal communities in Arizona, Oklahoma, North Dakota, or South Dakota. The authors explained that features of the built environment can lead to elevated lead exposure in tribal communities. This includes being exposed to lead through well water, local waterways, foods, including canned goods, herbs, and spices, as well as paint and dust.
For this retrospective review, the researchers looked at blood lead levels and blood pressure readings over time. Lead was first measured in blood collected during a 1997-1999 study visit and again in blood collected during a follow-up visit between 2006-2009. During these visits, participants had their blood pressure taken and participated in medical exams that included echocardiographs, a test to assess the heart’s structure and function. To support equal comparisons among participants, researchers controlled for multiple factors, including social variables, including education and income, cardiovascular disease risks, and medical history.
At the start of the study, the average blood lead level was 2.04 µg/dL. Throughout the study, the average blood lead level fell by 0.67 µg/dL, or 33%. The most significant changes occurred in participants with average starting blood lead levels of 3.21 µg/dL and who experienced reductions of about 1.78 µg/dL, or 55%. This drop was linked to a 7 mm Hg reduction in systolic blood pressure.
