Associations of objectively-assessed physical activity and sedentary time with hippocampal gray matter volume in children with overweight/obesity

Abstract

This study investigated physical activity (PA) and sedentary time (SED) in relation to hippocampal gray matter volume (GMV) in pediatric overweight/obesity. Ninety-three children (10 ± 1 year) were classified as overweight, obesity type I, or type II–III. PA was assessed with non-dominant wrist accelerometers. GMV was acquired by magnetic resonance imaging (MRI). Neither PA nor SED associated with GMV in the hippocampus in the whole sample (p > 0.05). However, we found some evidence of moderation by weight status (p < 0.150). Moderate-to-vigorous PA (MVPA) positively associated with GMV in the right hippocampus in obesity type I (B = 5.62, p = 0.017), which remained when considering SED, light PA, and sleep using compositional data (γ = 375.3, p = 0.04). Compositional models also depicted a negative association of SED relative to the remaining behaviors with GMV in the right hippocampus in overweight (γ = −1838.4, p = 0.038). Reallocating 20 min/day of SED to MVPA was associated with 100 mm3 GMV in the right hippocampus in obesity type I. Multivariate pattern analysis showed a negative-to-positive association pattern between PA of increasing intensity and GMV in the right hippocampus in obesity type II–III. Our findings support that reducing SED and increasing MVPA are associated with greater GMV in the right hippocampus in pediatric overweight/obesity. Further studies should corroborate our findings.MINECO/FEDER DEP2013-47540 DEP2016-79512-R RYC-2011-09011Spanish Ministry of Education, Culture and Sport FPU15/02645 FPU17/04802Government of Andalusian, Integrated Territorial Initiative 2014-2020 for the province of Cadiz PI-0002-2017Spanish Government FJC2018-037925-IAlicia Koplowitz FoundationSpanish Ministry of Economy and Competitiveness RTI2018-095284-J-100University of Granada, Plan Propio de Investigacion 2016, Excellence actions: Units of ExcellenceScientific Excellence Unit on Exercise and Health (UCEES)Junta de AndaluciaConsejeria de Conocimiento, Investigacion y UniversidadesEuropean Union (EU)SAMID III network, RETICS - PN I + D+I 2017-2021 (Spain)ISCIII-Sub-Directorate General for Research Assessment and PromotionEuropean Union (EU) RD16/0022EXERNET Research Network on Exercise and Health in Special Populations DEP2005-00046/ACT