Determinants of prostate-specific antigen levels in African men

BACKGROUND: Prostate-specific antigen (PSA) is widely used for screening and diagnosis of prostate cancer (CaP). Variation in PSA levels is influenced by age, genetics and other factors, yet this variation has not been well characterized in African men. METHODS: We used data on serum PSA extracted from medical records from prostate cancer cases and controls collected as part of the Men of African Descent and Carcinoma of the Prostate (MADCaP) network. We evaluate the association of PSA levels with country of origin, age, body mass index (BMI), and polygenic risk score (PRS). RESULTS: The median PSA levels were 41.8 (0.2-9696) ng/ml in 1,907 prostate cancer cases and 1.235 (0.01-9.72) ng/ml in 902 controls. Higher PSA levels were associated with increasing age, lower BMI, higher Gleason Score, and more advanced tumor stage in cases, explaining approximately 35% of variation in log-transformed PSA levels. In controls, 4.8% of PSA variation was explained by age. CONCLUSION: Our data in African men are consistent with non-African studies that report PSA levels increase with age, inversely with BMI (suggesting a PSA dilution effect or reverse causation), and with more aggressive disease in cases. These data may be used to help understand PSA distributions and in the future may guide screening practices in African men.