Objective: To assess the frequency of vitamin D deficiency among men with prostate cancer, as considerable epidemiological, in vitro, in vivo and clinical data support an association between vitamin D deficiency and prostate cancer outcome.
Patients, subjects and methods: The study included 120 ambulatory men with recurrent prostate cancer and 50 with clinically localized prostate cancer who were evaluated and serum samples assayed for 25-OH vitamin D levels. Then 100 controls (both sexes), matched for age and season of serum sample, were chosen from a prospective serum banking protocol. The relationship between age, body mass index, disease stage, Eastern Cooperative Oncology Group performance status, season and previous therapy on vitamin D status were evaluated using univariate and multivariate analyses.
Results: The mean 25-OH vitamin D level was 25.9 ng/mL in those with recurrent disease, 27.5 ng/mL in men with clinically localized prostate cancer and 24.5 ng/mL in controls. The frequency of vitamin D deficiency (<20 ng/mL) and insufficiency (20-31 ng/mL) was 40% and 32% in men with recurrent prostate; 28% had vitamin D levels that were normal (32-100 ng/mL). Among men with localized prostate cancer, 18% were deficient, 50% were insufficient and 32% were normal. Among controls, 31% were deficient, 40% were insufficient and 29% were normal. Metastatic disease (P = 0.005) and season of blood sampling (winter/spring; P = 0.01) were associated with vitamin D deficiency in patients with prostate cancer, while age, race, performance status and body mass index were not.
Conclusions: Vitamin D deficiency and insufficiency were common among men with prostate cancer and apparently normal controls in the western New York region.