Factors Associated With Vertebral Fractures in Men Treated With Androgen Deprivation Therapy for Prostate Cancer

Purpose: Androgen deprivation therapy for prostate cancer causes accelerated loss of bone mineral density and is associated with increased fracture risk. We evaluated risk factors associated with vertebral fractures among men enrolled in a fracture prevention trial. Materials and Methods: Analysis included men receiving androgen deprivation therapy for prostate cancer and enrolled in a phase III fracture prevention trial. All men were 70 years old or older or had a low bone mineral density (T-score less than -1.5 for the lumbar spine or total hip). We analyzed demographic and laboratory characteristics of men with and those without vertebral fractures at study entry. Results: Of the 1,244 subjects 162 (13.0%) had a vertebral fracture at baseline. The 2 factors significantly associated with vertebral fractures were white race (p = 0.028 compared with nonwhite race) and osteoporosis (p = 0.002 for osteoporosis at any site, p = 0.053 for osteoporosis at the spine, p = 0.002 for osteoporosis at the hip). Lower bone mineral density was also significantly associated with vertebral fractures when analyzed as a continuous variable. Factors not associated with vertebral fractures included age, country of residence, androgen deprivation therapy duration at baseline, androgen deprivation therapy mode, body mass index, testosterone, estradiol, C-telopeptide, bone specific alkaline phosphatase and osteocalcin. Results were similar in analyses limited to men 70 years old or older. Conclusions: White race and low bone mineral density were significantly associated with vertebral fractures in this study of men treated with androgen deprivation for prostate cancer. These observations should inform the assessment and management of fracture risk among such men.