Researchers Find Maine Adolescent Girls at Risk for Bone Loss and Future Fractures

in Health & Medicine, News Releases, School of Medicine
June 21st, 2005

Contact: Gina M. Digravio, 617-638-8491 | gina.digravio@bmc.org

(Boston) — Researchers at Boston University School of Medicine (BUSM) have found that adolescent girls living in Maine are at an increased risk for vitamin D deficiency, which may eventually compromise their bone health.

According to their report in the June issue of the Journal of the American Dietetic Association, the researchers also indicate that dietary intake goals for vitamin D should be higher than current recommendations.

Previous studies have shown that people living at northern latitudes are at an increased risk of vitamin D insufficiency during the winter because the sun’s rays are less direct, owing to its increased zenith angle to these latitudes. Vitamin D plays an integral role in bone mineralization by promoting calcium absorption in the small intestine and stimulating osteoblastic activity to maintain serum calcium and phosphorous levels.

An adequate supply of vitamin D is especially important to maximize gains in bone mineral during puberty. Puberty is a time of rapid bone growth and mineralization, with up to 50 percent of total adult bone mass accrued during this period.

For three years, each September and March the researchers measured serum 25-OHD (the standard indicator of vitamin D status) and parathyroid hormone levels of 23 girls between the ages of 9-11. Dietary intake of vitamin D and summer sun exposure were also analyzed. The average decrease in serum 25-OHD from September to March was 28 percent. Vitamin D insufficiency was observed in 48 percent (11 of 23) of the girls.

“Adolescent girls living at northern latitudes may be at particular risk for the deleterious effects of vitamin D insufficiency because of rapid bone mineralization rates during puberty, lack of vitamin D synthesis during winter, and the decrease in milk consumption that often occurs in adolescence,” says senior author Michael Holick, M.D., Ph.D., a professor of medicine, physiology, and biophysics at BUSM.

According to the researchers, there is a sizeable gap between the current serum vitamin D status and the desirable levels. “As the research continues, dietetic professionals should anticipate changes in the Dietary Reference Intake and in food fortification and supplementation practices,” adds Holick.

Susan S. Sullivan, D.Sc., and Clifford J. Rosen, M.D., from the University of Maine, collaborated on this study.

The Boston University School of Medicine, founded in 1848, is a leading academic and research institution, with an enrollment of nearly 1,000 students and more than 1,000 full-time faculty. Nationally renowned for its programs in heart disease, hypertension, stroke, pulmonary disease, arthritis, Alzheimer’s disease, autism, alcoholism and drug addiction, among others, in the past year it ranked 13th among U.S. medical schools in total dollars of National Institutes of Health funding.

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