A systematic review of previous MRI studies demonstrating the relationship between season and brain volume

IntroductionSpecific diseases such as Alzheimers, schizophrenia and multiple sclerosis have been associated with environmental changes, including changes in season. The relationship between changes in season or photoperiod and brain volume has been widely studied in animals. However, the relationship between changes in season and brain volume in humans is not yet well established. Here, we aim to provide a comprehensive and systematic review of magnetic resonance imaging (MRI) studies examining the effects of changes in season or photoperiod on brain volume. MethodsWe used a systematic review approach to study reports on the relationship between changes in season or photoperiod and brain volume using MRI. PubMed database and Google Scholar search engines were used to locate appropriate. PRISMA was used in selection of appropriate studies on season or photoperiod and brain volume using MRI. ResultsFive studies were included in the current review: three examined the relationship between changes in photoperiod and brain volumes while two studies examined the relationship between changes in season and brain volume. ConclusionWhen studying other variables like changes in temperature and humidity on how they affect brain volume, no effect was observed. It was, however, observed from studies that hydration status changed brain volumes when measured using MRI. Overall, we found evidence demonstrating differences in human brain volumes across different seasons. We suggest future longitudinal research to prove changes in brain volume across different seasons.