Purpose
To examine the role of body mass index (BMI) in assessment of prostate cancer (PCa) risk.
Materials and Methods
3,258 participants who underwent biopsy (including 1,902 men with a diagnosis of PCa) were identified from the Selenium and Vitamin E Cancer Prevention Trial. The associations of BMI with PCa and high-grade PCa (HGPCa) were examined using logistic regression, adjusting for age, race, BMI-adjusted prostate-specific antigen, digital rectal exam, family history of PCa, previous biopsy history, PSA velocity and time between study entry and the last biopsy. The prediction models were compared with our previously-developed BMI-adjusted Prostate Cancer Prevention Trial prostate cancer Risk Calculator (bmiPCPTRC).
Results
Of the study subjects, 49.1% were overweight and 29.3% were obese. After adjustment, among men without a known family history of PCa, increased BMI was not associated with higher risk of PCa (per one-unit increase in logBMI: OR=0.83, p=0.54) but was significantly associated with higher risk of HGPCa (i.e., Gleason score≥7 prostate cancer) (OR=2.31, p=0.03). For men with a known family history of PCa, the risks of PCa and HGPCa increased rapidly as BMI increased (PCa: OR=3.73, p=0.02; HGPCa: OR=7.95, p=0.002). The bmiPCPTRC generally underestimated the risks of PCa and HGPCa.
Conclusions
BMI provided independently predictive information regarding risks of PCa and HGPCa, after adjusting for other risk factors. BMI, especially among men with a known family history of PCa, should be considered for inclusion in any clinical assessment of PCa risk and recommendations regarding prostate biopsy.