CHICAGO, June 23: The same estrogen hormone elderly women take to fend off symptoms of menopause such as brittle bones likely helps them keep their teeth as well, researchers reported on Sunday.

A substantial portion of the elderly gradually lose their natural teeth and women are particularly vulnerable, with many cases thought to be associated with bone loss in the jaw, or alveolar, bone that surrounds the teeth.

Roughly 40 per cent of American women over age 65 do not have any of their natural teeth, and many suffer periodontal disease, according to the study, which was published in the Archives of Internal Medicine.

Just as estrogen has been shown to strengthen skeletal bones susceptible to osteoporosis, it has a similar impact on the alveolar bone and potentially prevents tooth loss, said researchers at the Washington University School of Medicine in St. Louis.

In the study of 135 women, roughly half took estrogen as well as calcium and vitamin D supplements and received regular dental checkups. The remaining women received the supplements and the checkups but substituted a placebo, or sugar pill, for the estrogen.

Those who received the hormone replacement therapy had an average 3.6 per cent gain in bone density in their femur, the leg bone joined to the hip, compared to an 0.2 per cent bone density improvement in those taking the placebo. In tests of the alveolar bone, density improved an average of 1.8 per cent among those taking estrogen, and 1 per cent among those taking a placebo. Women taking the placebo who had a slight improvement in bone density in their jaw bone did not show bone improvements elsewhere in their bodies.

“This means that perhaps you can prevent bone erosion in the jaw with calcium and vitamin D, but those supplements are not sufficient to restore bone loss,” said study author Dr. Roberto Civitelli, a professor of medicine, cell biology and physiology. —Reuters