BACKGROUND: Soluble Alpha-Klotho (S-αklotho) protein and 25-Hydroxyvitamin D (25-OH-D) have emerged as potential modulators for activating and recruiting Brown Adipose Tissue (BAT). The present study aimed to investigate whether circulating S-αklotho and 25-OH-D levels are related to BAT volume, METHODS: A total of 128 participants (68% women) aged 18-25 years old participated in this cross-sectional study. Serum levels of S-αklotho were determined by a solid-phase sandwich enzyme-linked immunosorbent assay kit and 25-OH-D serum levels were analyzed using a competitive chemiluminescence immunoassay, both in blood samples collected after an overnight fast. All participants underwent a personalized cold exposure to determine their BAT volume, RESULTS: After adjusting for multiple covariates, serum levels of S-αklotho (all R CONCLUSION: Serum S-αklotho and 25-OH-D levels within the physiological range are not related to BAT-related variables in young healthy adults. Further studies are needed to fully understand the underlying mechanisms involved in BAT metabolism in humans. (ACTIBATE
ClinicalTrials.gov identifier: not applicable).