Interplay between exercise and BMI; results from an equal access, racially diverse biopsy study

Abstract

Purpose: It is unclear if exercise and BMI interact to influence prostate cancer (PC) risk. We hypothesized BMI is linked with increased aggressive PC risk but this link will be attenuated with increased exercise. Methods: Men undergoing prostate biopsy completed a questionnaire and metabolic equivalent (MET) hours of exercise was calculated. Of 695 men, 349 had PC; 161 low-grade, and 188 high-grade. We assessed the link between exercise and PC risk, high-grade PC (Gleason 7–10), and low-grade PC (Gleason 2–6) using logistic and multinomial logistic regression. Analysis was stratified by BMI. Link between BMI and PC risk and aggressive PC was similarly tested. Results: On multivariable analysis, there was no link between exercise and PC diagnosis in the entire cohort (p trend = 0.18–0.71) or across BMI groups (p trend = 0.15–0.97). For the entire cohort, higher BMI was linked with increased risk of high-grade PC (OR 1.06, p = 0.008). When stratified by exercise groups, the trend for higher BMI and increased risk of high-grade PC remained (OR 1.03–1.15, p = 0.02–0.66). There were no interactions between exercise and BMI in predicting PC risk (all p ≥ 0.31). Conclusions: Regardless of exercise, higher BMI was linked with higher risk of aggressive PC, while exercise was unrelated to PC risk. Confirmatory studies are needed.