Vitamin D Deficiency at Diagnosis Increases All-Cause and Prostate Cancer-specific Mortality in Jamaican Men.

BACKGROUND: 25 hydroxyvitamin D [25(OH)D] and serum calcium have been associated with incident prostate cancer (PCa). However, there is limited data on whether these metabolites predict survival in men of African descent, a population disproportionately affected by PCa. We studied the relationship of 25(OH)D at PCa diagnosis with all-cause and cancer-specific mortality among Jamaican men and examined whether serum calcium modified any associations. METHODS: Serum 25(OH)D from 152 Jamaican men with incident PCa within the Prostate Cancer Risk Evaluation (PROSCARE) study were re-evaluated approximately 11 years after enrollment. 25(OH)D analyses were stratified using the using Holick criteria. PCa-specific and all-cause mortality were examined in Kaplan-Meier survival curves and Cox regression models adjusted for age, body mass index (BMI), smoking and Gleason score. Restricted cubic splines evaluated nonlinear associations. Serum calcium was assessed as an effect modifier of the association between 25(OH)D and mortality. RESULTS: Of cases with available 25(OH)D, 64 men with PCa survived, 38 deaths were PCa specific and 36 died of other causes. At baseline, 9.9% of cases were vitamin D deficient and 61.2% were vitamin D sufficient. Compared to 25(OH)D sufficient men, those with 25(OH)D <20.0 ng/mL concentrations were associated with higher PCa-specific mortality (adjusted HR, 4.95; 95% CI, 1.68, 14.63, P = .004) and all-cause mortality (adjusted HR, 2.40; 95%CI, 1.33, 4. 32, P = .003). Serum calcium was not associated with survival and did not modify any associations with 25(OH)D. CONCLUSIONS: 25(OH)D deficiency at PCa diagnosis predicted decreased survival for overall and PCa-specific cancer in Caribbean men of African ancestry.

Central adiposity at diagnosis may reduce prostate cancer-specific mortality in African-Caribbean men with prostate cancer: 10-year follow-up of participants in a case-control study.

PURPOSE: General and central adiposity are associated with the risk of developing prostate cancer (PCa), but the role of these exposures on PCa survival among men of African ancestry are less studied. This study aimed to investigate the association of anthropometry at diagnosis with all-cause and PCa-specific mortality and evaluate whether androgen deprivation therapy (ADT) modulated this risk. METHODS: Associations between body mass index (BMI), waist circumference (WC), and waist-to-hip ratio (WHR) at diagnosis and mortality were examined in 242 men with newly diagnosed PCa enrolled between 2005 and 2007 and re-evaluated 10.9 years later. Multi-variable Cox proportional hazard models were used to examine associations of body size variables (using standard WHO cut-points and as continuous variables) with mortality, adjusted for sociodemographic characteristics, Gleason score, smoking, diabetes, primary treatment, and ADT therapy. RESULTS: A total of 139 deaths (all-cause mortality 6.98/100 person-years) occurred (PCa-specific deaths, 56; other causes, 66; causes unknown, 17). In multi-variable analysis BMI, WC and WHR categories at diagnosis were not associated with all-cause mortality even after adjusting for ADT. While WHR (but not BMI or WC) when included as a continuous variable predicted lower PCa-specific mortality (multi-variable adjusted WHR per 0.1 difference: HR, 0.50; 95%CI 0.28, 0.93), the effect disappeared with ADT covariance and excluding deaths within the first 2 years. CONCLUSION: Our study suggests that central adiposity as measured by WHR may improve long-term survival among men of African ancestry. Metabolic studies to understand the mechanism for this association are needed.