Effect of obesity on prostate-specific antigen, prostate volume, and international prostate symptom score in patients with benign prostatic hyperplasia

PURPOSE

We examined the correlation between body mass index (BMI) as a marker of obesity and prostate-specific antigen (PSA), prostate volume (PV), and International Prostate Symptom Score (IPSS) in patients with benign prostatic hyperplasia (BPH).

MATERIALS AND METHODS

From January 2008 to December 2008, we examined 258 patients diagnosed with BPH. Patients taking 5α-reductase inhibitors or those diagnosed with prostate cancer were excluded from this study. BPH was defined as PV≥25 ml and IPSS≥8. BMI (kg/m(2)) was categorized into 4 groups as follows: BMI<18.5 (underweight), BMI 18.5-23.0 (normal), BMI 23.0-27.5 (overweight), and BMI>27.5 (obese). The relationships between PSA, PV, IPSS, and BMI were analyzed by correlation analysis and one-way ANOVA.

RESULTS

The mean age of the patients was 65.19±9.13 years and their mean BMI was 23.7±4.4 kg/m(2). The mean PSA values of each BMI group were as follows: 3.42±1.53, 3.07±1.88, 2.74±1.75, and 2.60±1.44 ng/ml. The PSA value was lowest in the obese group. The correlation analysis showed a negative correlation between BMI and PSA (Pearson's correlation coefficient=-0.142, p=0.023) and positive correlations between BMI and PV (Pearson's correlation coefficient=0.32, p=0.001) and IPSS (Pearson's correlation coefficient=0.470, p=0.02). These correlations were also confirmed by one-way ANOVA.

CONCLUSIONS

Patients with an elevated BMI tended to have lower PSA values, larger PVs, and a higher IPSS. We suggest that weight loss could be helpful for BPH symptom relief as well as for detection of coexisting prostate cancer in BPH patients.

Effects of obesity on lower urinary tract symptoms in Korean BPH patients

We analyzed the effects of obesity on lower urinary tract symptoms (LUTSs) in Korean benign prostatic hyperplasia (BPH) patients. This is a multicenter, cross-sectional, prospective study conducted in four centers in Korea. A total of 602 men with LUTSs secondary to BPH were included. BPH/LUTSs cases were men aged >/= 40 years with international prostate symptom scores (IPSS) > or = 8 points. Height, weight and waist circumference were measured. Among the 602 patients, 156 patients had a waist circumference above 90 cm, representing central obesity, and 215 patients had a body mass index above 25 kg m(-2). Waist circumference was positively correlated with prostate volume (P = 0.034). Men with waist circumference > 90 cm experienced a 1.36-fold increased risk of severe LUTSs (95% CI 0.82-2.41) compared with men with waist circumference < or = 90 cm. Prostate volume was positively correlated with urgency and nocturia in men with central obesity. In this population of Korean men diagnosed with BPH, central obesity rather than overall obesity seems to be the more important predictor of LUTSs correlated with BPH.