By Janet Raloff
Subtle bone loss associated with advanced gum disease can be linked to elevated lead concentrations in the blood, a new study finds.
A toxic metal, lead is best known in the public-health sector for causing nerve damage in children. However, it can also pose significant risks to adults by, for example, elevating blood pressure. Fortunately, the body stores most of the lead in newly forming bone, where it remains until that bone breaks down from disuse or disease.
Because the bacterial infections behind periodontal disease provoke an immune reaction that can eat away the jawbone, dentist Bruce A. Dye and his colleagues at the Centers for Disease Control and Prevention in Hyattsville, Md., searched for a correlation between the health of tissues surrounding people’s teeth and concentrations of lead in their blood. They used data on 10,000 U.S. adults from the Third National Health and Nutrition Examination Survey, which was completed in 1994.
In the October Environmental Health Perspectives, the researchers report that the average blood-lead concentration for these people was 2.5 micrograms per deciliter (g/dl). However, that average rose incrementally with increasing periodontal disease and bone loss in subsets of the population.
But the most tantalizing discovery, Dye says, was an apparent effect of smoking on bone’s release of lead. Cigarette smoke is itself a source of lead and can also exacerbate periodontal disease. In the new study, the share of smokers with potentially toxic concentrations of lead in their blood–at least 10 g/dl–was 4.6 percent, or four times that of nonsmokers. Dye says the new data indicate that smoking can exaggerate the effect of periodontal disease on blood lead.
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