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APHA Scientific Session and Event Listing

John R. Shaffer, Graduate School of Public Health, University of Pittsburgh, 114 Parran Hall, Pittsburgh, PA 15261, (412) 624-3002, jrinsky@asph.org

Background: Bone mass, the primary determinant of osteoporosis, is the net result of two factors: (1) acquisition of peak bone mass during young adulthood, and (2) subsequent rate of bone loss with age. While heritability of peak bone mass has been extensively studied, the genetic contribution to bone loss is largely unknown. We investigated the extent to which genes influence change in bone mineral density (BMD) over time in a sample of 18 extended Mexican American families (n=176, ages 45 to 78).

Methods: Annual BMD change was calculated from measurements of hip, spine, and radius BMD obtained by dual x-ray absorptiometry at baseline and follow-up (3-7 years later, median=5.5 years). Maximum likelihood methods were used to estimate heritability of change in BMD while simultaneously adjusting for the effects of age, sex, and body mass index.

Results and Conclusions: Heritability of change in BMD at hip, spine, and radius was 0.39 (p=0.009), 0.46 (p=0.007), and 0.45 (p=0.02), respectively. This study is the first to conclusively demonstrate the heritability of BMD change, showing that genetic factors account for approximately 40% of the variation in bone loss. Furthermore, the magnitude of heritability suggests that additional work to locate genes affecting bone loss may be fruitful. Discovery of such genes could lead to: (1) new biological targets for the treatment of osteoporosis, and/or (2) the identification of persons at risk for accelerated bone loss who would benefit from preventative interventions, resulting in improved health, improved quality of life, and reduction of medical care costs.

Learning Objectives:

• The educational mission of this abstract is to demonstrate the importance of genetic factors in the etiology of osteoporosis, a disease of profound public health significance, and to identify potential avenues for the clinical application of the research described herein.

Keywords: Genetics,

Presenting author's disclosure statement:

Not Answered