Now, new research from the University of Michigan’s School of Public Health suggests lead levels in the shin bones may be an unlikely culprit, specifically for treatment-resistant hypertension patients.
Resistant hypertension refers to blood pressure that remains above the recommended guidelines, despite treatment with three or more drugs from various classes.
“Laws limiting lead exposure have been on the books for decades, but in recent years it is recognized that lead remains an environmental toxin that is still with us,” study author Sung Kyun Park said in a news release.
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For the study, published Wednesday in the Journal of the American Heart Association, Park and his colleagues tested levels of lead in the blood, shin bones and kneecaps of 475 men with hypertension, all of whom were in Boston's Veterans Affairs Center. Approximately 97 percent of the men had treatment-resistant hypertension.
When adjusted for race, smoking habits, age and other factors, the scientists found that for every 15-microgram per gram increase in lead levels in the shone bone, there was a 19 percent high risk of treatment-resistant blood pressure.
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While previous research has proposed that lead may lead to hypertension, “our study demonstrates that cumulative lead burden, as measured by cortical bone in the tibia (shin bone), may be an unrecognized risk factor for drug-resistant hypertension,” Park said.
The cortical bone, according to Medical News Today, is the hard outer layer of bone. No statistically significant association was found with lead in the blood or kneecap.
But the study does have some limitations, such as the fact that treatment-resistant men may have been using over-the-counter medication or incorrectly taking their blood pressure medication. The researchers also only studied men, most of whom were white.
Read the full study at ahajournals.org.