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News Brief: December 2009
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Tuesday, January 5, 2010 Contacts: Contact: Arlyn G. Riskind
1. New Research Suggests Fat Mass Helps Build Bone Mass in Girls 1. New Research Suggests Fat Mass Helps Build Bone Mass in Girls Excessive reduction of fat mass in girls may increase risk of osteoporosis in later life According to a new study accepted for publication in The Endocrine Society’s Journal of Clinical Endocrinology & Metabolism (JCEM), fat mass is important in increasing bone size and thickness, but this effect appears to be stronger in girls than boys. Lean mass is one of the strongest determinants of bone mass throughout life. Until now, it has been unclear whether fat mass and lean mass differ in how they influence bone development in boys and girls. Findings from previous studies have been inconsistent regarding whether fat mass has a positive or negative impact on bone development. This new study shows that fat mass is a strong stimulus for the accrual of cortical bone mass (hard outer layer of bone) in girls. In this study, researchers used dual x-ray absorptiometry (DXA) to determine total body fat mass and lean mass, and peripheral quantitative computer tomography (pQCT) to measure cortical bone mass at the mid-tibia, in 4,005 boys and girls with a mean age of 15.5 years. Although lean mass was the major determinant of bone mass, fat mass also exerted an important positive influence, particularly in girls, in which the effect was approximately “The effect of fat mass on bone mass appears to be strongest in girls,” said Jonathan Tobias, PhD, of the University of Bristol in the United Kingdom, and lead author of the study. “Girls clearly have more fat mass than boys and our findings show that whereas the greater lean mass in boys contributes to their greater cortical bone mass, this effect is partly counteracted by the greater fat mass in girls.” “Fat mass in girls during puberty may have a long-term impact on bone health as they grow into adulthood,” said Tobias. “Excessive reduction in fat mass could have adverse effects on the developing skeleton particularly in girls, leading to an increased risk of osteoporosis in later life.” Adrian Sayers of the University of Bristol in the United Kingdom also worked on this study. The article, “Fat mass exerts a greater effect on cortical bone mass in girls than boys,” will appear in the February 2010 issue of JCEM. 2. HIV-Infected Postmenopausal Women at High Risk for Bone Fractures With potent therapies comes longer life for HIV-infected individuals, but with longer life comes metabolic complications According to a new study accepted for publication in The Endocrine Society’s Journal of Clinical Endocrinology & Metabolism (JCEM), postmenopausal HIV-infected women have a high prevalence of low bone mineral density and high bone turnover placing them at high risk for future bone fractures. “As HIV-infected individuals live longer with potent antiretroviral therapy (ART), metabolic complications such as low bone density and osteoporosis are increasingly recognized,” said Michael Yin, MD of Columbia University Medical Center in New York and lead author of the study. “Although numbers of HIV-infected postmenopausal women are increasing and postmenopausal women are at highest risk for osteoporotic fractures, few studies have evaluated skeletal status in this group. We hypothesized that postmenopausal women might be particularly vulnerable to the adverse effects of HIV infection or ART on the skeleton and our results indicate that this may indeed be the case.” To test their hypothesis, Yin and his colleagues initiated a longitudinal study to assess bone health in 92 HIV-positive and 95 HIV-negative postmenopausal women. Bone mineral density of the lumbar spine, femoral neck and hip as well as body composition were measured by dual x-ray absorptiometry (DXA). Researchers found that HIV-positive postmenopausal women had lower bone mineral density at both the spine and hip than HIV-negative postmenopausal women. “HIV infection was independently associated with lower bone mineral density after adjusting for body mass index (BMI) and traditional osteoporosis risk factors,” said Yin. “While the reason for HIV-associated bone loss remains unclear, it may be related to increased levels of cytokines (proteins produced by cells that aid communication between cells), direct effects of antiretrovirals on bone cells or hormonal/nutritional deficiencies that are common in HIV.” “Estrogen protects against the effect of cytokines on bone resorption,” said Yin. “Therefore, as HIV-positive women become estrogen deficient during menopause, they may be at higher risk for accelerated bone loss and fracture.” Other researchers working on the study include Don McMahon, Chiyuan Zhang, Aimee Shu, Ronald Staron, Ivelisse Colon, Jay Dobkin, Scott Hammer and Elizabeth Shane of Columbia University Medical Center in New York, N.Y.; David Ferris of Bronx-Lebanon Hospital Center in N.Y.; and Jeffrey Laurence of Weill Cornell Medical College in New York, N.Y. The article, “Low bone mass and high bone turnover in postmenopausal HIV-infected women,” will appear in the February 2010 issue of JCEM. 3. New Patient Fact Sheet on Klinefelter Syndrome Available The Hormone Foundation has published a new bilingual (English/Spanish) patient fact sheet on Klinefelter Syndrome. The fact sheet explains the genetic basis of the syndrome in simple terms. It outlines the varied signs and symptoms that may occur in infants and young boys, adolescents, and adults, as well as potential health problems associated with the syndrome. Treatment options, including testosterone replacement, are also covered. For more information visit: www.hormone.org.
# # # Founded in 1916, The Endocrine Society is the world's oldest, largest, and most active organization devoted to research on hormones and the clinical practice of endocrinology. Today, The Endocrine Society's membership consists of over 14,000 scientists, physicians, educators, nurses and students in more than 80 countries. Together, these members represent all basic, applied, and clinical interests in endocrinology. The Endocrine Society is based in Chevy Chase, Md. To learn more about the Society, and the field of endocrinology, visit our web site at www.endo-society.org. |