The likelihood of having a serum PSA level of ≥2.5 or ≥4.0 ng ml(-1) according to obesity in a screened Korean population.

This study aimed to determine if lower serum total prostate-specific antigen (PSA) levels in obese Korean men affect prostate cancer (PCa) screening, as an increased body mass index (BMI) is inversely associated with the PSA level. Between March 2007 and December 2012, 22 208 native Korean men who were eligible to receive a serum PSA test were recruited. Logistic regression was used to estimate the odds of an 'abnormal' PSA (≥2.5 or ≥4.0 ng ml(-1)) in these men (age: 45-75 years, PSA <10 ng ml(-1)) based on BMI, which was categorized as normal (BMI <25 kg m(-2)) and obese (BMI ≥25 kg m(-2)). In all, 20 509 men (92.3%) were included in the study after applying the inclusion criteria. After controlling for age, there was a statistically significant trend towards a lower likelihood of having a serum PSA level ≥2.5 ng ml(-1) with an increased BMI, with obese men having an 18% lower likelihood (odds ratio: 0.823, 95% confidence interval: 0.743-0.912; P<0.001) compared to men with a normal BMI. Obese men were approximately 82% as likely to have a PSA level ≥2.5 ng ml(-1) as men with a normal BMI. These results might affect PCa screening using serum total PSA. Further studies are needed to better define these results in clinical biopsy practice.