OBJECTIVES: This study aimed to investigate cross-sectional and longitudinal associations between fat mass (i.e. body mass index [BMI], waist circumference [WC] and waist-to-hip ratio [WTHR] and hippocampal volumes.
METHODS: UK Biobank participants (N = 20,395) aged 40-70 (mean follow-up = 7.66 years), were included and categorised into one of four groups, which represented their baseline fat mass status and trajectory of change by follow-up assessment: normal to overweight/obese (NO), overweight/obese to normal (ON), normal stable (NS) or overweight/obese stable (OS). Regression models used NS (WC < 80 cm in women and < 94 cm in men; WTHR < 0.85 in women and < 0.90 in men and BMI < 25 $kg/m^2$ in women and men), as the reference group. Hippocampal volumes were automatically segmented using FMRIB Software Library.
RESULTS: Compared to NS, OS (BMI: B = -62.23, standard error [SE] = 16.76; WC: B = -145.56, SE = 16.97 and WTHR: B = -101.26, SE = 19.54) and ON (BMI: B = -61.1, SE = 30.3; WC: B = -93.77, SE = 24.96 and WTHR: B = -69.92, SE = 26.22) had significantly lower hippocampal volumes.
CONCLUSIONS: The detrimental effects of overweight/obesity may extend beyond the duration of overweight/obesity itself.
Ambikairajah, A., Tabatabaei-Jafari, H., Walsh, E., Hornberger, M., & Cherbuin, N. (2020). Longitudinal changes in fat mass and the hippocampus. Obesity. doi:10.1002/oby.22819