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ARS Home » Northeast Area » Boston, Massachusetts » Jean Mayer Human Nutrition Research Center On Aging » Research » Publications at this Location » Publication #37932
Title: THE BSM-1 VITAMIN D RECEPTOR RESTRICTION FRAGMENT LENGTH POLYMORPHISM (BB) PREDICTS LOW BONE DENSITY IN PREMENOPAUSAL BLACK AND WHITE WOMEN

Author
item FLEET JAMES C - TUFTS-HNRCA
item HARRIS SUSAN S - TUFTS-HNRCA
item WOOD RICHARD J - TUFTS-HNRCA
item DAWSON-HUGHES BE - TUFTS-HNRCA

Submitted to: Journal of Bone and Mineral Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/16/1995
Publication Date: N/A
Citation: N/A

Interpretive Summary: Osteoporosis, a condition of low bone density leading to high rates of bone fracture, is a common disease that afflicts a substantial number of women in the U.S. Some studies have demonstrated that there is a strong genetic component to how strong or dense a person's bones are at any give time during the lifespan. Recently, researchers found a way of classifying women into groups with genetic predispositions to high (called the bb group) or low bone density (called the BB group). Most of the work in this new area has been done on postmenopausal white women. We have studied the role of the genotypic classification on bone density in a group of young (average age of 30 years old), premenopausal black and white women. We confirmed the natural tendency towards higher bone density in black women that others have reported. In addition, women in our study, regardless of race, who were in the BB group had lower bone density at two important sites: the lower spine and the leg bone that attaches into the hip. Our work is important for two reasons. First, we show that the negative consequences of being in the BB genetic classification can be seen relatively early in life. This suggests that preventative efforts to improve bone density must be started early in life to avoid the later occurrence of osteoporosis. Second, we find that racial differences in bone density are due to factors other than the BB genetic classification, thereby suggesting that additional factors remain to be identified that may ultimately be useful in helping people at risk for osteoporosis.

Technical Abstract: We conducted a study to determine whether a recently described restriction fragment length polymorphism in the vitamin D receptor gene (VDR-RFLP) predicts bone mineral density (BMD) in unrelated, premenopausal women as well as to determine the racial contribution to any genotypic influences on BMD. White (83) and black (72) women between 20 and 40 years of age were genotyped based on the presence (b) or absence (B) of a Bsm-1 restriction enzyme site in the VDR gene, and BMD in the lumbar spine and femur neck was determined for each subject. There were 16 BB, 73 Bb, and 66 bb women. Age and body mass index (BMI)-adjusted BMD was higher in black women at the spine (by 7.2%) and femur neck (7.3% higher). Mean BMD in the femur neck was lower in the BB women than the bb or Bb women (8.1 and 9.3% lower, respectively) after controlling for age, BMI, race, and a race by genotype interaction. Adjusted lumbar spine BMD was lower in the BB women than the Bb women (6.4% lower) in the group as a whole. The interaction of race and genotype on BMD was not significant at either site. Similar patterns of low BMD at the femur neck and the lumbar spine were seen in BB women of both races. No significant difference was observed in genotypic distribution between the racial groups. These data provide support for an association between low bone density and the BB genotype in a racially mixed, premenopausal population and suggests that this genotype may limit peak bone mass. Furthermore, racial differences in BMD appear to be independent from the VDR-genotype.