Higher Body Mass Index Increases the Risk for Biopsy-Mediated Detection of Prostate Cancer in Chinese Men

OBJECTIVE To investigate the relationship between body mass index (BMI) and prostate cancer (PCa) risk at biopsy in Chinese men. PATIENTS AND METHODS We retrospectively reviewed the records of 1,807 consecutive men who underwent initial multicore (≥10) prostate biopsy under transrectal ultrasound guidance between Dec 2004 and Feb 2014. BMI was categorised based on the Asian classification of obesity as follows: <18.5 (underweight), 18.5-22.9 (normal weight), 23-24.9 (overweight), 25-29.9 (moderately obese), and ≥30 kg/m2 (severely obese). The odds ratios (OR) of each BMI category for risk of PCa and high-grade prostate cancer (HGPCa, Gleason score ≥4+3) detection were estimated in crude, age-adjusted and multivariate-adjusted models. Prevalence ratios and accuracies of PSA predicted PCa were also estimated across BMI groups. RESULTS In total, PCa was detected by biopsy in 750 (45.4%) men, and HGPCa was detected in 419 (25.4%) men. Compared with men of normal weight, underweight men and obese men were older and had higher prostate specific antigen levels. The risk of overall PCa detection via biopsy presented an obvious U-shaped relationship with BMI in crude analysis. Overall, 50.0%, 37.4%, 45.6% 54.4% and 74.1% of the men in the underweight, normal weight, overweight, moderately obese and severely obese groups, respectively, were diagnosed with PCa via biopsy. In multivariate analysis, obesity was significantly correlated with a higher risk of PCa detection (OR = 1.17, 95%CI 1.10-1.25, P<0.001). However, higher BMI was not correlated with HGPCa detection (OR = 1.03, 95%CI 0.97-1.09, P = 0.29). There were no significant differences in the accuracy of using PSA to predict PCa or HGPCa detection across different BMI categories. CONCLUSION Obesity was associated with higher risk of PCa detection in the present Chinese biopsy population. No significant association was detected between obesity and HGPCa.