Osteoporosis and spinal fractures in men with prostate cancer: Risk factors and effects of androgen deprivation therapy

Purpose: We determined the risk factors for osteoporosis and spinal fractures in men with prostate cancer receiving androgen deprivation therapy. Materials and Methods: We performed a retrospective analysis of 87 consecutive men with prostate cancer receiving androgen deprivation therapy referred for evaluation of osteoporosis. Data were comprised of lateral thoracolumbar radiographs, bone densitometry, serum biochemistry and a detailed assessment of osteoporotic risk factors. Multivariate regression analysis was used to determine the major risk factors for osteoporosis and spinal fractures. Results: There were 38 (44%) men who were 74.5 years old with radiographic evidence of spinal fractures. They had an initial mean prostate specific antigen of 52.8 ng/ml and had received androgen deprivation therapy for a mean of 39.6 months (95% confidence interval 28.7 to 50.4). Mean spinal (quantitative computerized tomography t-score -4.2) and femoral neck bone mineral densities (dual energy x-ray absorptiometry t-score -2.1) were significantly lower than in men without spinal fractures (p <0.001 for all measurements). In the regression analysis the duration of androgen deprivation therapy (p =0.002), serum 25-hydroxyvitamin D levels (p =0.003) and a history of alcohol excess (defined as more than 4 standard drinks daily, p =0.04) were the main determinants of spinal fractures. Conclusions: Prolonged androgen deprivation therapy, low serum 25-hydroxyvitamin D levels and a history of alcohol excess are important risk factors for osteoporosis and spinal fractures in men with prostate cancer.