Effect of body mass index and waist circumference on prostate specific antigen and prostate volume in a generally healthy Korean population.

PURPOSE We examined the influences of age, body mass index and waist circumference on prostate specific antigen before and after adjusting for prostate volume. We also examined associations among age, body mass index, waist circumference and prostate volume. MATERIALS AND METHODS We analyzed 38,380 Korean men 30 to 79 years old who received regular checkups at our health examination center. We had prostate volume data for 3,593 of them. We divided the subjects into 5 groups by age, 4 groups by body mass index and waist circumference (using Asia-Pacific obesity reference values), and quartiles for prostate volume. We compared prostate specific antigen and prostate volume by multivariate regression analysis across body mass index and waist circumference after adjusting for age and/or prostate volume. RESULTS Increasing body mass index or waist circumference was associated with decreasing prostate specific antigen (with or without prostate volume adjustment) and increasing prostate volume (p for trend <0.01). When we stratified prostate volume by quartile, age was not associated with prostate specific antigen except in quartile 4 (p for trend by quartile 0.402, 0.639, 0.056 and <0.01). Mean prostate specific antigen of the group with a body mass index less than 23 in prostate volume quartile 4 was approximately 3 times that of the group with a body mass index greater than 30 in prostate volume quartile 1 (1.42 vs 0.55). CONCLUSIONS Obesity had a negative association with prostate specific antigen regardless of prostate volume, and a positive association with prostate volume. Age was not associated with prostate specific antigen after prostate volume adjustment. Obese men, especially those with a small prostate volume, may have lower baseline prostate specific antigen and, thus, be at higher risk for having prostate cancer undetected in a prostate specific antigen screening test.