Body mass index influences prostate-specific antigen in men younger than 60 years of age

Prostate-specific antigen (PSA) levels can be affected by many factors. Body mass index (BMI) is suspected to influence PSA levels, but the associations are controversial. The aim of this study was to examine whether PSA levels were affected by BMI and age in Koreans.

We evaluated the association between BMI and PSA in a group of 8640 Korean men (aged 40-79 years) without prostate cancer who received a general health checkup. Eligible men were classified into age groups spanning 10 years. BMI was categorized as normal (BMI <22.9), overweight (BMI 23.0-24.9), obese (BMI 25.0-29.9), and very obese (BMI > or =30) according to the re-defined World Health Organization (WHO) criterion for the Asia Pacific Region. PSA levels were stratified by age and BMI category.

Prostate-specific antigen levels decreased with increasing BMI (P trend <0.001). However, the inverse correlations between PSA and BMI were significant only among men 40-59 years old (P trend <0.05, respectively). BMI showed no significant associations with PSA in 60-79 years old (P trend >0.05, respectively).

Our study demonstrates that increased BMI is associated with decreased PSA levels only in men younger than 60 years of age. When determining whether to carry out prostate biopsy as part of early prostate cancer detection, obesity should be considered as a factor associated with reduced PSA in healthy young men (<60 years old) with marginal PSA levels.