Abstract
Abstract Introduction For accurate evaluation clinicians must consider the variations that testosterone undergoes in the human body. The diurnal variation of testosterone is well characterized, levels peak in the morning and decline during the day. Seasonal variations in testosterone levels have been reported in some studies, but the results are inconsistent. Thus, there is a lack of consensus on whether there are significant seasonal variations in serum testosterone levels. Objective In this study, we aimed to determine if clinically relevant seasonal variability in testosterone levels exists using a large cohort of men from two different institutions, one located in an area with seasons (Pittsburgh, Pennsylvania) and one without seasons (Miami, Florida). Methods Using two institutional databases, testosterone levels were obtained for men ages 18-99 from 2010-2021 who had at least 2 morning testosterone levels drawn within a 2-year period. All samples were analyzed with liquid chromatography with tandem mass spectrometry (LC-MS/MS). To avoid potential confounding by testosterone altering medications patients who were currently or previously on exogenous testosterone, endogenous testosterone stimulating medications, testosterone suppressing medications, and aromatase inhibitors were excluded from the study. Results There were 9495 and 16171 total testosterone levels measured from Miami and Pittsburgh respectively, with all men having 2 or more levels (Table 1). There was no statistically significant variation in T levels for the overall cohort in Pittsburgh or Miami, respectively (Table 2). Additionally, when stratified by age group, no individual groups were found to have significant seasonal variability (Table 3). Conclusions Our findings suggest that although there is differing total testosterone levels between men who reside in two different climates, there is no significant variability in testosterone levels between seasons. Therefore, testosterone levels can be checked and interpreted without the need to account for the season during which they were drawn. Disclosure No.