Longitudinal Changes in Fat Mass and the Hippocampus
Ananthan Ambikairajah, Hossein Tabatabaei‐Jafari, Erin Walsh, Michael Hornberger, Nicolas Cherbuin
Abstract
Objective 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 to 70 years (mean follow‐up = 7.66 years), were included and categorized into one of four groups, which represented their baseline fat mass status and trajectory of change by follow‐up assessment: normal weight to overweight/obesity, overweight/obesity to normal weight (ON), normal weight stable (NS), or overweight/obesity 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; BMI < 25 kg/m 2 in women and men) as the reference group. Hippocampal volumes were automatically segmented using the FMRIB Software Library. Results Compared with NS, OS (BMI: B = −62.23 [SE = 16.76]; WC: B = −145.56 [SE = 16.97]; WTHR: B = −101.26 [SE = 19.54]) and ON (BMI: B = −61.1 [SE = 30.3]; WC: B = −93.77 [SE = 24.96]; 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.