The relationship between daily calcium intake and bone mineral density in men with prostate cancer

OBJECTIVE: To analyse the relationship between daily calcium intake (DCI) and bone mineral density (BMD) in patients with prostate cancer, and to assess if DCI is a risk factor for osteoporosis in this group of patients. PATIENTS AND METHODS: DCI was assessed by a standard questionnaire answered by men with prostate cancer who had had bone densitometry. BMD was measured by dual-energy X-ray absorptiometry in the lumbar spine and different hip sites, in a cross-sectional study including 372 men with prostate cancer free of bone metastases, 71.5% (266) under androgen-deprivation therapy (ADT) and 28.5% (106) after radical prostatectomy (RP). Osteoporosis was defined according to the International Society for Clinical Densitometry official position (2005). RESULTS: A DCI of <1000 mg, the National Institute of Health recommendation, was detected in 93% of the men, (93.5% under ADT and 91.5% after RP). Osteoporosis was identified in 49.2% (183) of the patients, 54.9% (146) under ADT and 34.9% (37) after RP. The mean DCI was 609.7 mg in men with osteoporosis and 682.8 mg in those without (P < 0.001); in men under ADT the mean DCI remained significantly lower in those with osteoporosis (615.5 vs 700.4 mg, P < 0.001). A multivariate analysis showed that DCI was an independent risk factor for osteoporosis, together with patient age, ADT and its duration. CONCLUSIONS: DCI seems to be related to BMD; a low DCI was an independent risk factor for osteoporosis in men with prostate cancer. In the study population overall the DCI was inadequate. Urologists should recommend a DCI of >1000 mg in patients with prostate cancer, especially in those under ADT. © 2007 The Authors.