Effect of obesity on serum prostate-specific antigen in Nigerian men

Lower serum total prostate-specific antigen (PSA) levels (tPSA) have been reported in obese men. It has not been confirmed if this association truly exists in all ethnic groups. Thus, we evaluated the relationship between tPSA and obesity among Nigerian men.

Men aged ≥ 40 years with tPSA <20 ng/ml and no known prostatic disease were involved. Obesity was defined using the body mass index (BMI) and waist to hip ratio (WHR). Multivariate linear regression was used to investigate the relationship between tPSA and either BMI or WHR. The odds of having abnormal tPSA were estimated using logistic regression.

A total of 3,191 men participated, and 3,049 (95.6%) were eligible for analysis. A BMI ≥ 25.0 and a WHR ≥ 0.9 were found in 47.7 and 64.6%, respectively. tPSA was significantly associated with age (p < 0.001) and digital rectal examination status (p < 0.001). Multivariate linear regression analysis showed no relationship between tPSA and obesity (BMI, p = 0.581; WHR, p = 0.160). Adjusting for age and digital rectal examination status, logistic regression showed no significantly observable trend of having a tPSA level greater than thresholds for men with a BMI ≥ 25 or a WHR ≥ 0.9 when compared with normal BMI or WHR, respectively.

Although overweight and obesity were common among healthy Nigerian men, there was no associated tendency towards lower serum tPSA.