Association of Cumulative Ultraviolet Radiation Exposure with Prostate Cancer Risk in a Case-control Study of African-American Men

Abstract

It is well established that exposure to ultraviolet (UV) radiation has beneficial effects in reducing prostate cancer risk. To determine if there is a correlation between UV exposure and prostate cancer risk, we assessed sun exposure in a case-control study of 182 African-American men aged 40 years and older residing in the Metropolitan Washington, DC area. Using data on cumulative exposure per year and adult sunbathing scores derived from a validated questionnaire, analysis revealed significant difference in cumulative sun exposure between cases and controls (p=0.003). Additionally, the outdoor and recreation UV exposures were significantly higher in controls when compared to cases (p=0.003; p=0.03 in age-matched cases and controls). Although the results of conditional logistic regression analysis indicate that there was no association between total UV exposure and risk of prostate cancer after adjusting for age (OR=2.04, 95% CI 0.54-7.70, p=0.29), outdoor UV exposure was associated with decreased prostate cancer risk (OR= 0.31, 95% CI 0.14-0.65, p=0.002). Furthermore, a trend for reduced prostate cancer risk was found among men with early life high sun exposure during childhood ages 0-5 years (OR=0.17, 95% CI 0.03-0.74, p=0.02) and 6-11 years (OR= 0.28, 95% CI 0.07-1.05, p=0.06). Interestingly, this inverse association between prostate cancer risk and early life high sun exposure intensity was also observed among young men at ages 12-17 years although not statistically significant (OR=0.41, 95% CI 0.09-1.95, p=0.26). These findings indicate that UV exposure earlier in life may affect susceptibility to prostate cancer.