Lifestyle factors and duration of androgen deprivation affect bone mineral density of patients with prostate cancer during first year of therapy

OBJECTIVES Androgen deprivation therapy (ADT) is associated with loss of bone mineral density (BMD) and increased fracture risk. We sought to examine the impact of ADT and lifestyle variables on BMD in 120 patients with prostate cancer without bone metastases entering a randomized clinical trial. METHODS A total of 120 patients with prostate cancer and without bone metastases who had been treated with ADT for less than 12 months were enrolled in a clinical trial of zoledronic acid versus placebo. BMD measurements of the femoral neck, total hip, and lumbar spine were obtained before starting the study treatment by dual energy x-ray absorptiometry. The subjects answered a questionnaire regarding possible osteoporosis risk factors, including dairy product use, caffeinated beverage use, smoking history, alcohol intake, calcium/vitamin D supplementation, thyroid medication, and exercise. RESULTS The median duration of ADT was 3 months (range 0 to 12). Osteopenia or osteoporosis (T score of less than -1) was detected in two thirds of the subjects at one or more measured sites. The mean baseline BMD Z scores were femoral neck -0.091 0.959, total hip 0.122 +/- 1.005, and lumbar spine 0.657 1.789. On multiple linear regression analysis, the duration of ADT was negatively associated with the Z score at all three sites and the body mass index, calcium/vitamin D supplementation, and alcohol use were positively associated with the Z score. CONCLUSIONS BMD loss is a function of the duration of ADT during the first year of therapy. The body mass index, calcium/vitamin D supplementation, and alcohol use were associated with greater BMD, even after controlling for ADT exposure.