Urinary estrogen metabolites, prostate specific antigen, and body mass index among African-American men in South Carolina

Introduction: Estrogen metabolites have been linked to risk of breast cancer, and we were interested in whether they are associated with prostate specific antigen (PSA) and other factors associated with prostate cancer. African-American (AA) men in South Carolina have among the highest prostate cancer rates in the world, and thus provide an ideal population in which to investigate this hypothesis. Methods: We recruited AA men attending prostate cancer screenings in and around Columbia, South Carolina. Because very few men had elevated PSAs, we restricted our study to the 77 men whose PSA was below the cutpoint used by the screening program to indicate need for diagnostic workup. These men provided spot urine samples and answered demographic and lifestyle questions including self-reported body weight, height, exercise, tobacco use, medications, cancer history and age. Levels of urinary 2-hydroxyestrone (2-OHE1) and 16α-hydroxyestrone (16α-OHE1), and their ratio (2/16) and blood PSA levels were determined. Results: After adjusting for a statistically significant interaction between age and BMI, we found a reduction of 14.2% in 2-OHE1 for each 1.0 ng/ml increase in PSA (p = 0.05). For obese AA men only (BMI ≥ 30 kg/m2), 2-OHE1 increased by 36% for each decade of age (p = 0.009). Conclusions: Estrogen metabolites may be related to PSA level in AA men. Older men with BMIs greater than 30 kg/m2 had an unexpected increase in 2-OHE1, suggesting a dysregulation of this estrogen metabolism pathway. Further studies of estrogen metabolites may provide insights into prostate cancer risk factors.