TY - JOUR
T1 - Isotemporal Substitution Effects of Daily Time Use on Cardiorespiratory Fitness of Children in the OptiChild Study
T2 - A Mediation Analysis with Diet Quality
AU - Wang, Youxin
AU - Zhang, Pingping
AU - Wang, Mingyue
AU - Gong, Qinghai
AU - Yu, Canqing
AU - Wang, Haijun
AU - Hebestreit, Antje
AU - Lau, Patrick W.C.
AU - Wang, Hui
AU - Li, Li
N1 - This study was supported by grants from Major Science and Technology Projects for Health of Zhejiang Province (Grant No. WKJ-ZJ-2216), Cyrus Tang Foundation for Young Scholar 2022 (2022-B126) and Zhejiang Provincial Natural Science Foundation of China (LTGY24H260007).
Publisher Copyright:
© 2024 by the authors.
PY - 2024/8/21
Y1 - 2024/8/21
N2 - (1) Background: Although daily time-use is associated with diet quality and cardiorespiratory fitness (CRF) in children, their interdependence remains unexplored. This study first examined the associations between reallocating daily movement time and diet quality and CRF, and second the mediating role of diet quality in the relationship between daily time-use and CRF. (2) Methods: This study included 1131 Chinese children (aged 8 to 10 years; median [interquartile range]: 8.5 [8.3, 8.8]) at baseline (September 2022) and 1268 children at the 9-month follow-up (June 2023) from the OptiChild study. Daily durations of moderate-to-vigorous physical activity (MVPA), sleep, and sedentary behavior (e.g., screen time) were self-reported or proxy-reported by parents. Diet quality was assessed via the Diet Quality Questionnaire (DQQ), which uses a 24 h dietary recall and is categorized according to the Global Dietary Recommendations (GDR) score and Food Group Diversity Score (FGDS). The CRF was measured using VO2max after the 20 m shuttle run test. Longitudinal associations between daily time-use, diet quality, and CRF were calculated using isotemporal substitution models. Mediation analyses were used to determine whether diet quality mediated the associations between daily time-use and CRF. (3) Results: Reallocation of 30 min from screen time to MVPA resulted in significant improvements in the GDR score (β baseline = 0.11, p = 0.024; β follow-up = 0.26, p < 0.001), FGDS (β baseline = 0.11, p = 0.006; β follow-up = 0.19, p < 0.001), and CRF (β baseline = 0.40, p < 0.001; β follow-up = 0.26, p = 0.001). Diet quality partially mediated the associations between MVPA, screen time, and CRF. Substituting 30 min of screen time for MVPA led to diet quality mediating a proportion of the association with CRF (GDR score: 11.4%, FGDS: 6.6%). (4) Conclusions: These findings underscore the importance of optimizing daily time-use of MVPA and screen time and improving diet quality to promote physical fitness in school-aged children.
AB - (1) Background: Although daily time-use is associated with diet quality and cardiorespiratory fitness (CRF) in children, their interdependence remains unexplored. This study first examined the associations between reallocating daily movement time and diet quality and CRF, and second the mediating role of diet quality in the relationship between daily time-use and CRF. (2) Methods: This study included 1131 Chinese children (aged 8 to 10 years; median [interquartile range]: 8.5 [8.3, 8.8]) at baseline (September 2022) and 1268 children at the 9-month follow-up (June 2023) from the OptiChild study. Daily durations of moderate-to-vigorous physical activity (MVPA), sleep, and sedentary behavior (e.g., screen time) were self-reported or proxy-reported by parents. Diet quality was assessed via the Diet Quality Questionnaire (DQQ), which uses a 24 h dietary recall and is categorized according to the Global Dietary Recommendations (GDR) score and Food Group Diversity Score (FGDS). The CRF was measured using VO2max after the 20 m shuttle run test. Longitudinal associations between daily time-use, diet quality, and CRF were calculated using isotemporal substitution models. Mediation analyses were used to determine whether diet quality mediated the associations between daily time-use and CRF. (3) Results: Reallocation of 30 min from screen time to MVPA resulted in significant improvements in the GDR score (β baseline = 0.11, p = 0.024; β follow-up = 0.26, p < 0.001), FGDS (β baseline = 0.11, p = 0.006; β follow-up = 0.19, p < 0.001), and CRF (β baseline = 0.40, p < 0.001; β follow-up = 0.26, p = 0.001). Diet quality partially mediated the associations between MVPA, screen time, and CRF. Substituting 30 min of screen time for MVPA led to diet quality mediating a proportion of the association with CRF (GDR score: 11.4%, FGDS: 6.6%). (4) Conclusions: These findings underscore the importance of optimizing daily time-use of MVPA and screen time and improving diet quality to promote physical fitness in school-aged children.
KW - cardiorespiratory fitness
KW - children
KW - diet quality
KW - physical activity
KW - screen time
UR - http://www.scopus.com/inward/record.url?scp=85202594194&partnerID=8YFLogxK
U2 - 10.3390/nu16162788
DO - 10.3390/nu16162788
M3 - Journal article
C2 - 39203923
AN - SCOPUS:85202594194
SN - 2072-6643
VL - 16
JO - Nutrients
JF - Nutrients
IS - 16
M1 - 2788
ER -
