Search

Abstract Background In 1995, a study was conducted to identify the effects of traditional and westernized environments on the prevalence of type 2 diabetes in Pima Indians (Pimas) in Mexico and the United States. The study concluded that the more traditional lifestyle in Mexico had a protective effect against this metabolic disorder. In the ensuing 15 years, the environmental circumstances of the Mexican Pimas changed, and a follow-up study was conducted to determine the role environmental change plays in the development of diabetes in this genetically susceptible population. A major element of environmental transition relates to land-use and land-cover (LULC) changes that could affect physical activity and promote an obesogenic environment. This study examined changes in the region’s LULC to determine whether there have been transitions in agricultural land use and urbanization that would be consistent with a more sedentary lifestyle. Changes were assessed from 1994 aerial photographs and 2007 satellite images. Results The land-cover analysis showed that mixed vegetation and dense trees cover most of the study area. It suggested a rural environment that includes a low percentage of impermeable areas, and it indicated that the area experiencing human intervention covers 7% of the total area. The land-use-change findings showed a decrease or no change in agricultural or ranching areas and a decrease in farmland due to reforestation or revegetation. Three variables from the land-use-change analysis were examined as proxies for lifestyle change: urban development, dwelling-unit density, and variation in the road network. Two of the measures –the amount of urbanization and the number and density of dwelling units—showed increases, most notably in the town of Maycoba. There were only minor changes in the road network: most of the road segments are short and concentrated in Maycoba where most of the buildings, points of interest (e.g., church, stores), and cars are located. Conclusions The LULC in Maycoba and surrounding settlements had changed during the study period. LULC change was used as a proxy to examine lifestyle changes that can affect levels of physical activity.

Introduction: Indigenous populations worldwide who are shifting to a westernized lifestyle experience high rates of type 2 diabetes and obesity. These conditions are commonly the result of genetic predisposition and environmental factors that promote excess energy intake and decreased energy expenditure. The purpose of this study was to examine changes in the food environment, specifically looking at retail and subsistence-food availability, and food-acquisition behaviors in the rural Mexican town of Maycoba and surrounding communities between 1995 and 2010. The population in this area includes indigenous Pima, genetically-related to the Pima Indians in Arizona who have the highest documented rates of diabetes, and non-Pima Mexican (ie non indigenous and other indigenous). An initial study in 1995 compared the prevalence of diabetes and obesity in the Maycoba population with that of Pima Indians of Arizona and found a dramatically lower type 2 diabetes prevalence in the Maycoba region due to the protective effect of a traditional lifestyle despite a genetic predisposition to diabetes., Methods: The 2010 follow-up study was undertaken to determine the prevalence of obesity and type 2 diabetes as well as to examine lifestyle changes over the 15 year time span, following changes to housing and the local environment. This study focused on the food environment, examining changes in food acquisition behaviors in the retail and subsistence aspects. The study included a household survey (n=71), two focus group discussions, and participant-observation. To determine changes in retail food availability, seven stores throughout the study region were audited., Results: The main findings were an increasing presence and use of retail stores for food: an expansion in the selection of processed foods, their prominent placement, and refrigeration allowing more perishable foods to be available to the local population. Subsistence activities remained significant, although some aspects of specific subsistence activities are in decline, such as the area allocated to home gardens and a reduction in the variety of crops cultivated in them., Conclusion: Although there have been a number of changes in the food environment during the 15 year period, a traditional subsistence-based lifestyle prevails.