Presentation Authors: Mahmoud Mima*, C.Danielle Tan, Rodrigo L Pagani, Chicago, IL, Stephen J Freedland, Los Angeles, CA, Gerald L Andriole, St. Louis, MO, Samuel J Ohlander, Daniel M Moreira, Chicago, IL
Introduction: Sex steroid levels vary by geographic location suggesting environmental factors may influence hormone production. We used data from Reduction by Dutasteride in Prostate Cancer Events (REDUCE) trial to identify differences in baseline androgen levels and sexual function between North American and European men.
Methods: We evaluated 5,825 men aged 50-75 years in the REDUCE trial. Subjects were divided in North Americans (NA) and Europeans (E). Differences in baseline demographics, comorbidities, laboratory results and questionnaire-based sexual function (Problem Assessment Scale of Sexual Function Index: PAS-SFI) between groups were evaluated using univariate and multivariate analyses. Subgroup analyses further dividing Europeans into Eastern and Western were performed as above.
Results: 1,912 (32.8%) were NA and 3,913 (67.2%) were E men (3,157 Western and 756 Eastern E). NA were significantly younger (mean age 61.6 vs 63.2 years), heavier (mean body-mass index 28.3 vs 27.1 kg/m2), less likely to be white (87.4% vs 99.6%), had greater prevalence of diabetes (9.9% vs 7.5%) and hypertension (44.0% vs 38.4), and less likely to be current smokers (12.9% vs 15.8%; all P < 0.01). Despite having significantly lower mean total testosterone (TT) levels (432.1 vs 451.6 nmol/L, P=0.001), NA had greater sexual activity (83.0% vs 80.1%, P=0.007) and comparable PAS-SFI scores, libido, and erectile dysfunction (ED) rates to E in univariable analysis. In multivariable analysis, these differences were no longer statistically significant (Table). In subgroup analysis dividing E in Eastern and Western, Eastern E had higher TT levels, lower PAS-SFI scores, and lower libido but similar sexual activity compared to NA (all P < 0.01). Western E had similar TT levels, PAS-SFI scores, sexual activity, and libido (p>0.05), but less ED than NA (P < 0.05).
Conclusions: We found significant differences in TT and sexual function between NA and E. Specifically, NA had lower TT and higher sexual activity rates, denoting weak correlation between serum TT levels and sexual function. Although some differences in sexual function were explained by imbalances in baseline patient characteristics, it is likely unmeasured factors such as the environment and lifestyle may influence serum TT and sexual function.