Longitudinal association between density of retail food stores and body mass index in Mexican school children and adolescents.

BACKGROUND: Obesity is rapidly increasing in Mexican children and adolescents, while food environments are rapidly changing. We evaluated the association between changes in retail food stores and change in body mass index (BMI) in Mexican children and adolescents. METHODS: Data on 7507 participants aged 5-19 years old came from the Mexican Family Life Survey 2002-2012. Density of food stores at the municipal-level (number of food stores/area in km2) came from the Economic Censuses of 1999, 2004 and 2009. We categorized food stores as small food retail (small neighborhood stores, tiendas de abarrotes in Mexico), specialty foods, fruit/vegetables, convenience foods, and supermarkets. Associations between change in food stores and change in BMI were estimated using five longitudinal linear fixed-effects regression models (one per type of food store) adjusted for age, parental education, municipal-level socioeconomic deprivation and population density. Density of each food store type was operationalized as quartiles. Analyses were stratified by urbanization. RESULTS: There was an inverse dose-response association between increases in fruit/vegetable store density and BMI (ß = -0.455 kg/m2, ß = -0.733 kg/m2, and ß = -0.838 kg/m2 in the second, third, and fourth quartile). In non-urban areas, children living in municipalities with the highest density of small food retail stores experienced a reduction in BMI (ß = -0.840 kg/m2). In urban areas, there was an inverse association between specialty food stores with BMI (ß = -0.789 kg/m2 in third quartile, and ß = -1.204 kg/m2 in fourth quartile). We observed dynamic associations with age; results suggested stronger associations in adolescents. CONCLUSIONS: The availability of fruit/vegetable stores may influence a reduction in children and adolescents BMI. These results indicate that policy approaches could be tailored by type of food store - with some consideration for level of urbanization and children's age.

Socioeconomic deprivation and changes in the retail food environment of Mexico from 2010 to 2020.

We aimed to analyze the change in the retail food environment of Mexican municipalities from 2010 to 2020, and to assess if these trends were modified by socioeconomic deprivation. We used data from the National Statistical Directory of Economic Units. Changes in the food store count were estimated using fixed-effects Poisson regression models, including coefficients for time, socioeconomic deprivation, and their interaction. We found a rapid growth in convenience stores, seed-grain stores, and supermarkets while small food retail stores declined. Urban areas had a higher count of all types of food stores; however, the steepest increases in food stores were observed in non-urban areas. The increase in convenience stores, supermarkets, specialty food stores, fruit-vegetable stores, and seed-grain stores was greater in the most deprived areas, compared to the least deprived areas. There has been a substantial expansion and rapid change in Mexico's food environment, mainly driven by increases in convenience stores and supermarkets in more deprived and less urbanized areas.

Potential impacts of policies to reduce purchasing of ultra-processed foods in Mexico at different stages of the social transition: an agent-based modelling approach.

OBJECTIVES: To develop a simulation framework for assessing how combinations of taxes, nutrition warning labels and advertising levels could affect purchasing of ultra-processed foods (UPF) in Latin American countries and to understand whether policies reinforce or reduce pre-existing social disparities in UPF consumption. DESIGN: We developed an agent-based simulation model using international evidence regarding the effect of price, nutrition warning labels and advertising on UPF purchasing. SETTING: We estimated policy effects in scenarios representing two stages of the 'social transition' in UPF purchasing: (1) a pre-transition scenario, where UPF purchasing is higher among high-income households, similar to patterns in Mexico; and (2) a post-transition scenario where UPF purchasing is highest among low-income households, similar to patterns in Chile. PARTICIPANTS: A population of 1000 individual agents with levels of age, income, educational attainment and UPF purchasing similar to adult women in Mexico. RESULTS: A 20 % tax would decrease purchasing by 24 % relative to baseline in both the pre- and post-transition scenarios, an effect that is similar in magnitude to that of a nutrition warning label policy. A 50 % advertising increase or decrease had a comparatively small effect. Nutrition warning labels were most effective among those with higher levels of educational attainment. Labelling reduced inequities in the pre-transition scenario (i.e. highest UPF purchasing among the highest socio-economic group) but widened inequities in the post-transition scenario. CONCLUSIONS: Effective policy levers are available to reduce UPF purchasing, but policymakers should anticipate that equity impacts will differ depending on existing social patterns in UPF purchasing.

Educational inequalities in obesity: a multilevel analysis of survey data from cities in Latin America.

OBJECTIVE: Using newly harmonised individual-level data on health and socio-economic environments in Latin American cities (from the Salud Urbana en América Latina (SALURBAL) study), we assessed the association between obesity and education levels and explored potential effect modification of this association by city-level socio-economic development. DESIGN: This cross-sectional study used survey data collected between 2002 and 2017. Absolute and relative educational inequalities in obesity (BMI ≥ 30 kg/m2, derived from measured weight and height) were calculated first. Then, a two-level mixed-effects logistic regression was run to test for effect modification of the education-obesity association by city-level socio-economic development. All analyses were stratified by sex. SETTING: One hundred seventy-six Latin American cities within eight countries (Brazil, Chile, Colombia, Costa Rica, El Salvador, Guatemala, Mexico and Peru). PARTICIPANTS: 53 186 adults aged >18 years old. RESULTS: Among women, 25 % were living with obesity and obesity was negatively associated with educational level (higher education-lower obesity) and this pattern was consistent across city-level socio-economic development. Among men, 18 % were living with obesity and there was a positive association between education and obesity (higher education-higher obesity) for men living in cities with lower levels of development, whereas for those living in cities with higher levels of development, the pattern was inverted and university education was protective of obesity. CONCLUSIONS: Among women, education was protective of obesity regardless, whereas among men, it was only protective in cities with higher levels of development. These divergent results suggest the need for sex- and city-specific interventions to reduce obesity prevalence and inequalities.

Adolescent Tobacco Exposure in 31 Latin American Cities before and after the Framework Convention for Tobacco Control.

Our objective was to describe the prevalence and changes in tobacco use and tobacco control policies in Latin American countries and cities before and after ratification of the 2003 Framework Convention on Tobacco Control (FCTC). Country-level tobacco policy data came from reports on the global tobacco epidemic (World Health Organization, 2007-2014). Global Youth Tobacco Survey data, 2000-2011, came from six countries (Argentina, Brazil, Chile, Colombia, Mexico, Peru), 31 cities and 132,065 students. Pre- and post-FCTC prevalence and relative changes were estimated. All countries showed improvements in tobacco control policies but Mexico and Peru showed the smallest improvements. In general, adolescents reduced their tobacco use, reported less exposure to smoking at home, more tobacco education, and more retailer refusals to sell them cigarettes. Adolescents reported smaller reductions in secondhand smoke exposure outside the home and no change in exposure to tobacco media/promotions. Pre-FCTC prevalence and relative changes during the post-FCTC period were more heterogeneous across cities than across countries. Despite overall improvements in tobacco policies and the decline in exposure to tobacco, policies related to media/promotions and secondhand smoke need strengthening. There was wide variation in adolescent exposure to tobacco between cities (within countries), which suggested major heterogeneity of policy implementation at the local level.

Longitudinal changes in the retail food environment in Mexico and their association with diabetes.

The retail food environment is a potential population-level determinant of diet and nutrition-related chronic diseases, yet little is known about its composition and association with diabetes in low- and middle-income countries. Our objectives were: (1) to describe changes in the composition of the retail food environment in Mexican neighborhoods from 2010 to 2016 and (2) to examine the association between these changes and diabetes cases diagnosed over the same period. Individual level data came from the 2016 Mexican Health and Nutrition Survey (N = 2808 adults). Neighborhood level retail food environment data for 2010 and 2016 came from the National Directory of Economic Units of Mexico. Multilevel logistic regression was used to examine the adjusted association between changes in the neighborhood density per km2 of fruit and vegetable stores, chain convenience stores and supermarkets with diabetes. Small store formats still predominate in Mexico's food environment, however there is evidence of fast increase in chain convenience stores and supermarkets. Adults living in neighborhoods that saw a decline in fruit and vegetable store density and a simultaneous increase in chain convenience store density experienced higher odds of diabetes, compared to adults who lived in neighborhoods where fruit and vegetable and convenience stores did not change (OR 3.90, 95% CI 1.61, 9.48). Considering the complex interplay between store types, understanding the mechanisms and confirming the causal implications of these findings could inform policies that improve the quality of food environments in cities.

The food environment in Latin America: a systematic review with a focus on environments relevant to obesity and related chronic diseases.

OBJECTIVE: Food environments may be contributing to the rapid increase in obesity occurring in most Latin American (LA) countries. The present study reviews literature from LA that (i) describes the food environment and policies targeting the food environment (FEP); and (ii) analytic studies that investigate associations between the FEP and dietary behaviours, overweight/obesity and obesity related chronic diseases. We focus on six dimensions of the FEP: food retail, provision, labelling, marketing, price and composition. DESIGN: Systematic literature review. Three databases (Web of Science, SciELO, LILACS) were searched, from 1 January 1999 up to July 2017. Two authors independently selected the studies. A narrative synthesis was used to summarize, integrate and interpret findings. SETTING: Studies conducted in LA countries. PARTICIPANTS: The search yielded 2695 articles of which eighty-four met inclusion criteria. RESULTS: Most studies were descriptive and came from Brazil (61 %), followed by Mexico (18 %) and Guatemala (6 %). Studies were focused primarily on retail/provision (n 27), marketing (n 16) and labelling (n 15). Consistent associations between availability of fruit and vegetable markets and higher consumption of fruits and vegetables were found in cross-sectional studies. Health claims in food packaging were prevalent and mostly misleading. There was widespread use of marketing strategies for unhealthy foods aimed at children. Food prices were lower for processed relative to fresh foods. Some studies documented high sodium in industrially processed foods. CONCLUSIONS: Gaps in knowledge remain regarding policy evaluations, longitudinal food retail studies, impacts of food price on diet and effects of digital marketing on diet/health.

Neighborhood Physical Environment and Changes in Body Mass Index: Results From the Multi-Ethnic Study of Atherosclerosis.

Longitudinal associations between neighborhood characteristics and body mass index (BMI; weight (kg)/height (m)2) were assessed from 2000 to 2011 among 5,919 participants in the Multi-Ethnic Study of Atherosclerosis. The perceived availability of healthy food and walking environment were assessed via surveys, and 1-mile (1.6-km) densities of supermarkets, fruit-and-vegetable stores, and recreational facilities were obtained through a commercial database. Econometric fixed-effects models were used to estimate the association between within-person changes in neighborhood characteristics and within-person change in BMI. In fully adjusted models, a 1-standard-deviation increase in the healthy food environment index was associated with a 0.16-kg/m2 decrease in BMI (95% confidence interval (CI): -0.27, -0.06) among participants with obesity at baseline. A 1-standard-deviation increase in the physical activity environment index was associated with 0.13-kg/m2 (95% CI: -0.24, -0.02) and 0.14-kg/m2 (95% CI: -0.27, -0.01) decreases in BMI for participants who were overweight and obese at baseline, respectively. Paradoxically, increases in the physical activity index were associated with BMI increases in persons who were normal-weight at baseline. This study provides preliminary longitudinal evidence that favorable changes in neighborhood physical environments are related to BMI reductions in obese persons, who comprise a substantial proportion of the US population.

Brief introductory guide to agent-based modeling and an illustration from urban health research.

There is growing interest among urban health researchers in addressing complex problems using conceptual and computation models from the field of complex systems. Agent-based modeling (ABM) is one computational modeling tool that has received a lot of interest. However, many researchers remain unfamiliar with developing and carrying out an ABM, hindering the understanding and application of it. This paper first presents a brief introductory guide to carrying out a simple agent-based model. Then, the method is illustrated by discussing a previously developed agent-based model, which explored inequalities in diet in the context of urban residential segregation.

Brief introductory guide to agent-based modeling and an illustration from urban health research / Breve guia introdutório de modelagem baseada em agentes e uma ilustração a partir da pesquisa em saúde urbana / Breve guía introductoria de modelación basada en agentes y una ilustración a partir de la investigación en salud urbana

Abstract There is growing interest among urban health researchers in addressing complex problems using conceptual and computation models from the field of complex systems. Agent-based modeling (ABM) is one computational modeling tool that has received a lot of interest. However, many researchers remain unfamiliar with developing and carrying out an ABM, hindering the understanding and application of it. This paper first presents a brief introductory guide to carrying out a simple agent-based model. Then, the method is illustrated by discussing a previously developed agent-based model, which explored inequalities in diet in the context of urban residential segregation.

Resumo Há um interesse crescente entre os pesquisadores de saúde urbana em trabalhar com problemas complexos utilizando modelos conceituais e computacionais do campo de sistemas complexos. A modelagem baseada em agentes (MBA) é uma ferramenta computacional de modelagem que tem recebido crescente interesse. No entanto, vários pesquisadores ainda não se sentem familiarizados com o desenvolvimento e a execução de uma MBA, dificultando a sua aplicação e compreensão. Este artigo primeiramente apresenta um breve guia introdutório para executar um simples modelo baseado em agentes. Em seguida, o método é ilustrado discutindo um modelo baseado em agente previamente desenvolvido, que explora as desigualdades na dieta no contexto da segregação residencial urbana.

Resumen Existe un interés creciente entre los estudiosos de la salud urbana en trabajar con problemas complejos, utilizando modelos conceptuales y computacionales del campo de sistemas complejos. La modelación basada en agentes (MBA) es una herramienta de modelación computacional que suscita cada vez más interés. Sin embargo, varios estudiosos todavía no se encuentran familiarizados con el desarrollo e implementación de un MBA, lo que dificulta su aplicación y comprensión. En este artículo se ofrece inicialmente una breve guía introductoria para llevar a cabo un simple modelo basado en agentes. De esta manera el método se ilustra discutiendo un modelo basado en agentes, desarrollado previamente, que explora las desigualdades en la dieta en un contexto de segregación residencial urbana.