The Association between Fast Food Outlets and Overweight in Adolescents Is Confounded by Neighbourhood Deprivation: A Longitudinal Analysis of the Millennium Cohort Study
Mark A. Green; Matthew Hobbs; Ding Ding; Michael Widener; John Murray; Lindsey Reece; Alex Singleton (2021). International Journal of Environmental Research and Public Health, 18(24), 13212. DOI: 10.3390/ijerph182413212
Abstract
The aim of our study is to utilise longitudinal data to explore if the association between the retail fast food environment and overweight in adolescents is confounded by neighbourhood deprivation. Data from the Millennium Cohort Study for England were obtained for waves 5 (ages 11/12; 2011/12; n = 13,469) and 6 (ages 14/15; 2014/15; n = 11,884). Our outcome variable was overweight/obesity defined using age and sex-specific International Obesity Task Force cut points. Individuals were linked, based on their residential location, to data on the density of fast food outlets and neighbourhood deprivation. Structural Equation Models were used to model associations and test for observed confounding. A small positive association was initially detected between fast food outlets and overweight (e.g., at age 11/12, Odds Ratio (OR) = 1.0006, 95% Confidence Intervals (CI) = 1.0002–1.0009). Following adjusting for the confounding role of neighbourhood deprivation, this association was non-significant. Individuals who resided in the most deprived neighbourhoods had higher odds of overweight than individuals in the least deprived neighbourhoods (e.g., at age 11/12 OR = 1.95, 95% CIs = 1.64–2.32). Neighbourhood deprivation was also positively associated to the density of fast food outlets (at age 11/12 Incidence Rate Ratio = 3.03, 95% CIs = 2.80–3.28).
Extended Summary
This research examined whether neighbourhood deprivation explains the relationship between fast food outlet density and adolescent overweight in England. Using longitudinal data from the Millennium Cohort Study, researchers tracked 9,736 participants across England at ages 11-12 (2011/12) and 14-15 (2014/15). The study linked participant residential locations to data on fast food outlet density from the Food Standards Agency and neighbourhood deprivation scores using the Index of Multiple Deprivation. Overweight status was determined using internationally validated age and sex-specific cut-off points. The research employed Structural Equation Models to test specific pathways between fast food environments, neighbourhood deprivation, and adolescent body weight, moving beyond simple associational analyses to examine underlying mechanisms. Initial findings suggested a small positive association between fast food outlet density and overweight risk at the city/town level. However, this association disappeared completely when neighbourhood deprivation was properly accounted for in the analysis. The study revealed strong social gradients in adolescent overweight, with young people in the most deprived neighbourhoods having 95% higher odds of being overweight compared to those in the least deprived areas. Crucially, the research demonstrated that fast food outlets cluster heavily in deprived neighbourhoods, with the most deprived areas having three times more outlets than affluent areas. When examining participants who moved between areas with different fast food densities, no association was found between changes in outlet exposure and overweight risk. Additional analyses incorporating physical activity and fast food consumption patterns confirmed that neighbourhood deprivation remained the key factor, with socioeconomically disadvantaged adolescents more likely to consume fast food frequently and exercise less. The findings challenge the effectiveness of planning policies that restrict fast food outlets near schools or limit outlet density, suggesting these interventions may be ineffective without addressing underlying social inequalities. Instead, the research indicates that policy efforts should focus on poverty alleviation and mediating the effects of deprivation, such as subsidising healthy foods in schools or shops. The study contributes important longitudinal evidence to a field dominated by cross-sectional research, demonstrating how sophisticated analytical methods can reveal that apparent environmental effects on health may actually reflect deeper structural inequalities in society.
Key Findings
- Fast food outlet density showed no independent association with adolescent overweight after accounting for neighbourhood deprivation
- Adolescents in the most deprived neighbourhoods had 95% higher odds of overweight compared to least deprived areas
- Fast food outlets cluster heavily in deprived areas, with threefold higher density in most versus least deprived neighbourhoods
- Planning policies restricting fast food outlets may be ineffective without addressing underlying social inequalities
- Longitudinal analysis revealed neighbourhood deprivation as the fundamental driver of both food environments and adolescent obesity
Citation
@article{green2021association,
author = {Mark A. Green; Matthew Hobbs; Ding Ding; Michael Widener; John Murray; Lindsey Reece; Alex Singleton},
title = {The Association between Fast Food Outlets and Overweight in Adolescents Is Confounded by Neighbourhood Deprivation: A Longitudinal Analysis of the Millennium Cohort Study},
journal = {International Journal of Environmental Research and Public Health},
year = {2021},
volume = {18(24)},
pages = {13212},
doi = {10.3390/ijerph182413212}
}