Planas J et al. (2007) The relationship between daily calcium intake and bone mineral density in men with prostate cancer. BJU Int 99: 812–816

Researchers from Spain have revealed a significant relationship between a low daily calcium intake (DCI) and the risk of osteoporosis in men with prostate cancer.

Androgen deprivation therapy (ADT) is the standard treatment for metastatic prostate cancer, and loss of bone mineral density (BMD) leading to osteoporosis is a widely reported side-effect of ADT. To investigate the relationship between DCI and BMD, Planas et al. analyzed the results of a standard questionnaire filled out by prostate cancer patients who had undergone bone densitometry. Of the 372 participants, 106 had clinically localized prostate cancer treated by radical prostatectomy and were free of biochemical progression, and 266 had clinically advanced disease but no bone metastases, and were treated with ADT.

In total, 93% of patients were found to have a DCI below the recommended level (≥1000 mg/day). The rate of osteoporosis was significantly higher in patients undergoing ADT compared with those treated by radical prostatectomy (54.9% vs 34.9%; P <0.001). Mean DCI did not significantly differ according to ADT status. However, DCI was significantly lower in patients with osteoporosis than in those without (609.7 mg vs 682.8 mg; P <0.001), regardless of hormonal status. Multivariate analysis revealed DCI (P <0.001), patient age (P <0.02), and ADT status (P <0.003) and duration (P <0.001) to be independent risk factors for the development of osteoporosis.

These findings support the recommended optimum DCI of >1000 mg/day in patients with prostate cancer. The authors recommend that BMD is assessed before initiating ADT and monitored throughout treatment.