Does the association between later eating rhythm and childhood adiposity differ between the UK and China?

Abstract

The prevalence of childhood adiposity, an important predictor of adult chronic disease, is rising. Later eating rhythm (LER), termed night eating in adult studies, refers to later timing, greater energy intake (EI), and higher meal frequency in the evening. The role of LER in adiposity is emerging, but most evidence is cross-sectional, considers just one feature of LER, and is rarely studied in children. This thesis comprises five studies investigating the association of LER with adiposity in children, and compares results between western and eastern cohorts.
The systematic review and meta-analysis including 47 studies suggested positive associations of higher EI around bedtime and evening main meal skipping, with adiposity. However, the evidence is of very low certainty due to inconsistent definitions of LER, lack of adjustment for confounders, and reliance on cross-sectional studies. To address these limitations, a review of the definition of LER was conducted; a set of operative and comparable definitions of LER, developed based on this review, was applied to two cohorts [Avon Longitudinal Study of Parents and Children (ALSPAC) in the UK (n=4869, age 7.5yrs) and China Health and Nutrition Survey (CHNS) (n=1749, age 7.5yrs)]. The cohorts showed different prevalence and characteristics of LER, and potentially different confounding structures due to cultural differences.
Secondary analyses of ALSPAC and CHNS data were conducted to investigate the prospective associations between LER and adiposity at 2-3yrs follow-up. These showed positive associations in both studies between LER after the evening main meal and adiposity, but not when including the evening main meal. The cross-context comparison study provides evidence of causation between evening snack frequency and adiposity.
This thesis highlights the importance of regulating LER after the evening main meal. EI in the evening should be regarded with caution despite no associations with adiposity being observed. Further high-quality cohorts are warranted to confirm these findings.

Date of Award	24 Jan 2023
Original language	English
Awarding Institution	University of Bristol
Supervisor	Sam D Leary (Supervisor) & Kate Northstone (Supervisor)