Cross-sectional and prospective mediating effects of dietary intake on the relationship between sedentary behaviour and body mass index in adolescents

BMC Public Health

Research Article

Jo Salmon¹  Sarah A. McNaughton¹  Karen E. Lamb¹  Elly A. Fletcher¹  David W. Dunstan²  Sarah P. Garnett³  Louise A. Baur³ 

[1] Deakin University, Geelong, Australia, Institute for Physical Activity and Nutrition (IPAN), School of Exercise and Nutrition Sciences, Geelong, Australia;Deakin University, Geelong, Australia, Institute for Physical Activity and Nutrition (IPAN), School of Exercise and Nutrition Sciences, Geelong, Australia;Baker IDI Heart and Diabetes Institute, Melbourne, VIC, Australia;Department of Medicine, Monash University, Melbourne, Australia;The University of Queensland, School of Public Health, Brisbane, Australia;Department of Epidemiology and Preventive Medicine, Monash University, Melbourne, Australia;School of Sport Science, Exercise and Health, The University of Western Australia, Perth, Australia;Mary MacKillop Institute for Health Research, Australian Catholic University, Melbourne, Australia;The Children’s Hospital at Westmead Clinical School, University of Sydney, Westmead, Australia;

关键词: Television viewing;    Sedentary behaviour;    Dietary intake;    BMI;    Adolescents;   

DOI  :  10.1186/s12889-017-4771-0

 received in 2017-01-29, accepted in 2017-09-18,  发布年份 2017

来源: Springer

【 摘 要 】

BackgroundCross-sectional evidence suggests TV viewing, but not objectively-measured sedentary time or bouts of sedentary time, is consistently associated with body mass index (BMI) in adolescents. However, it is unclear whether dietary intake is a potential mediator of these relationships. The aim of this study was to explore the cross-sectional and prospective mediating effects of dietary intake on the association of sedentary behaviour with BMI z-score (zBMI) in a cohort of Australian adolescents.MethodsCross-sectional and prospective analyses were conducted in adolescents aged 12–15 years participating in the 2002/03 (baseline) and 2004/05 (follow-up) Nepean Growing Up Study. The independent variables were television (TV) viewing, an objective measure of total sedentary time and average sedentary bout duration, and the outcome variable zBMI. Using the Sobel-Goodman method with bootstrapping, mediation analyses were conducted examining three dietary components (discretionary foods, sugar-sweetened beverages [SSB] and takeaway foods) as mediators of associations between TV viewing and zBMI (n = 259) and between total sedentary time and average sedentary bout duration with zBMI (n = 140).ResultsNo significant cross-sectional or prospective total or direct associations were observed for TV viewing, total sedentary time and average sedentary bout duration with zBMI. However, TV viewing was positively associated with consumption of takeaway foods cross-sectionally (β = 0.06; 95% CI 0.01 to 0.12), prospectively at baseline (β = 0.07; 95% CI 0.01 to 0.12) and prospectively at follow-up (β = 0.10; 95% CI 0.04, 0.16), and average sedentary bout duration was inversely associated with SSB consumption both cross-sectionally (β = −0.36; 95% CI -0.69 to −0.02) and prospectively at baseline (β = −0.36; 95% CI -0.70 to −0.02). No mediation effects were identified.ConclusionsTV viewing, total sedentary time and bouts of sedentary time were not associated cross-sectionally or prospectively with adolescents’ zBMI, and three elements of dietary intake (e.g. intake of discretionary foods, SSB and takeaway foods) did not mediate this relationship. The role of dietary intake and sedentary behaviour in relation to adolescent health requires further clarification.

【 授权许可】

CC BY   
© The Author(s). 2017