Osteoporosis: Identification of factors associated with fracture, bone mineral density, bone geometry and bone strength in older adult

Osteoporosis is a major public health problem in men and women. Low bone mineral density (BMD) is a major risk factor for fracture. Fractures have major implications for morbidity and mortality.;This research project evaluated correlates of trabecular and cortical vBMD at the radius and tibia in primarily Caucasian men aged 69 years or older using the Osteoporotic Fractures in Men study (MrOS). The correlation between serum 25-hydroxy vitamin D [25(OH)D] and bone density, content, geometry and strength was also assessed using Caucasian men from MrOS and men of African descent from the Tobago Bone Health Study, aged 65 years and older. We also investigated the longitudinal impact of serum leptin and adiponectin on bone loss and fractures in the Health Aging and Body Composition study (Health ABC) in men and women, aged 70 years and older, of African American and Caucasian descent.;Our findings have important public health implications. We have a better understanding of how different factors are correlated with trabecular and cortical and vBMD. Future research can generate hypotheses to evaluate these associations prospectively. Men of African descent had significantly higher 25(OH)D than Caucasians, which has never been reported. Serum 25(OH)D was positively correlated with indices of bone strength in Caucasian men, but not men of African descent. Serum 25(OH)D thresholds were identified at an estimated 20 ng/ml (lower than previous consensus of 30 ng/ml), greater levels of 25(OH)D had minimal effects on bone measures. Significant correlations between 25(OH)D occurred only at cortical regions. Prospective studies that evaluate the impact of 25(OH)D on trabecular and cortical vBMD loss are needed. There was an association between higher adiponectin and greater risk of incident fracture in men only. We also report that adiponectin predicted greater hip areal BMD (aBMD) loss among women, but not men. The impact of leptin on bone loss and incident fractures was largely attenuated by BMI and weight change. This study provides strong evidence that higher levels of adiponectin may increase the risk of bone loss and fracture. Studies are needed to explain these differential associations for adiponectin in women and men.