AUTHOR=Castillo-Aguilar Matías , Mabe-Castro Diego , Mabe-Castro Matías , Mendes Thiago Teixeira , Concha-Cisternas Yeny , Guzmán-Muñoz Eduardo , Núñez-Espinosa Cristian 

TITLE=The winter is coming: seasonal variations in BDNF levels among older adults in a high-latitude region — a preliminary study

JOURNAL=Frontiers in Psychiatry

VOLUME=Volume 16 - 2025

YEAR=2025

URL=https://www.frontiersin.org/journals/psychiatry/articles/10.3389/fpsyt.2025.1692566

DOI=10.3389/fpsyt.2025.1692566

ISSN=1664-0640

ABSTRACT=ObjectiveTo evaluate seasonal changes in plasma Brain-Derived Neurotrophic Factor (BDNF) from the start to the end of winter and identify moderating factors.MethodsAn observational longitudinal study of 17 community-dwelling older adults (mean age 76.4 ± 5.6 years; 12 women) was conducted with assesments performed at the beginning and at the end of the winter, which included multi-frequency bioelectrical impedance analysis for body composition, standardized physical performance testing, cognitive and anxiety screening, and plasma BDNF quantification by enzyme-linked immunosorbent assay. Data were analyzed using hierarchical Bayesian mixed-effects models with time-by-covariate interaction terms; inference was based on posterior medians and 95% highest-density credible intervals.ResultsPlasma BDNF decreased from the first to the second assessment. This association remained after adjustment for baseline cognitive performance and anxiety. Physical performance was not associated with attenuation of the seasonal decline.ConclusionsIn this small longitudinal cohort, winter was associated with a reduction in plasma BDNF in older adults, independent of baseline cognition and anxiety. These results require replication in larger samples.