ProCEED Pilot Study (Prostate Cancer Study of Ethnicity, Exercise and Diet)

The ProCEED pilot study was a case-control study that was undertaken to assess the epidemiology of prostate cancer in Illinois as compared to the United States; differences in levels of IGF-1 and IGFBP-3 in blood samples from prostate cancer cases compared to controls; differences in dietary and exercise intake between case-control groups; and potential interactions between lifestyle variables and IGF-1 level. The clinical portions of this study were undertaken in the General Urology Clinic at the Jesse Brown Veteran’s Adminsitration Medical Center, Chicago, Illinois. A total of 84 subjects were enrolled: 59 prostate cancer cases and 25 controls. The cases were significantly older than controls (70.6 versus 63.2, p=.0020). Both groups were predominately African Americans (83% cases versus 84% controls). More cases than controls were not working at the time of the study (84.8% versus 62.5%, p=.0053). Prostate cancer cases had been seen in the JBVMAC General Urology clinic for the following treatments: hormone therapy (37%), watchful waiting (27%), prostatectomy (37%), radiation (22%), brachytherapy (2%). The total Gleason scores for the prostate cancer cases were as follow: 5 (1.7%), 6 (42.4%), 7 (37.3%), 8 (8.5%), 9 (10.2%). After controlling for covariates, there was a statistically significant and slightly negative association for IGF-1 and prostate cancer (OR 0.96, C.I. 0.93–0.99). In dietary analyses, adjusted carbohydrate intake, daily calorie intake, and age remained statistically significant predictors of prostate cancer (all p<.05) and total adjusted dietary fiber intake was a significant protective factor (p=.0262), after controlling for covariates. Effect modification between IGF-1 and the total daily intakes of fiber and carbohydrates showed borderline significance, but brought the associations toward the null. In this predominately African American, inner-city population, there were slightly decreased odds of developing the disease with elevated levels of IGF hormones; and carbohydrates, fiber, total daily calories, and age were significant predictors of prostate cancer. Thus, diets lower on the glycemic index (lower simple carbohydrate and higher fiber intake) may be protective for prostate cancer.