Risk of prostate cancer in African-American men: Evidence of mixed effects of dietary quercetin by serum vitamin D status.

BACKGROUND: African-American (AA) men experience higher rates of prostate cancer (PCa) and vitamin D (vitD) deficiency than white men. VitD is promoted for PCa prevention, but there is conflicting data on the association between vitD and PCa. We examined the association between serum vitD and dietary quercetin and their interaction with PCa risk in AA men. METHODS: Participants included 90 AA men with PCa undergoing treatment at Howard University Hospital (HUH) and 62 controls participating in HUH's free PCa screening program. We measured serum 25-hydroxy vitD [25(OH)D] and used the 98.2 item Block Brief 2000 Food Frequency Questionnaires to measure dietary intake of quercetin and other nutrients. Case and control groups were compared using a two-sample t-test for continuous risk factors and a Fisher exact test for categorical factors. Associations between risk factors and PCa risk were examined via age-adjusted logistic regression models. RESULTS: Interaction effects of dietary quercetin and serum vitD on PCa status were observed. AA men (age 40-70) with normal levels of serum vitD (>30 ng/ml) had a 71% lower risk of PCa compared to AA men with vitD deficiency (OR = 0.29, 95%CI: 0.08-1.03; P = 0.055). In individuals with vitD deficiency, increased dietary quercetin showed a tendency toward lower risk of PCa (OR = 0.91, 95%CI: 0.82-1.00; P = 0.054, age-adjusted) while men with normal vitD were at elevated risk (OR = 1.23, 95%CI: 1.04-1.45). CONCLUSION: These findings suggest that AA men who are at a higher risk of PCa may benefit more from vitD intake, and supplementation with dietary quercetin may increase the risk of PCa in AA men with normal vitD levels. Further studies with larger populations are needed to better understand the impact of the interaction between sera vitD levels and supplementation with quercetin on PCa in AA men.

Infectious crystalline keratopathy.

In three patients (three men, 44, 67, and 83 years old) an unusual keratopathy characterized by white, branching, crystalline stromal opacities produced lesions that were insidious, that increased in size slowly, and that were clinically and histopathologically associated with little corneal inflammation. Intraocular inflammation eventually became evident in two of the patients. The keratopathy developed while the patients were using topical corticosteroids. In two cases, histopathologic studies disclosed accumulations of gram-positive cocci in the corneal stroma; a viridans streptococcus agent was isolated on culture. In one case, the viridans streptococcus was determined to be a dextran producer, which may have contributed to the pathogenesis of the keratopathy. Despite aggressive treatment with a variety of drugs, epithelial healing, and resolution of the corneal infiltrate, residual scarring persisted in two cases and neovascularization and graft edema in one case each.