Environmentally Driven Increases in Type 2 Diabetes and Obesity in Pima Indians and Non-Pimas in Mexico Over a 15-Year Period: The Maycoba Project

Abstract

OBJECTIVEThe global epidemics of type 2 diabetes and obesity have been attributed to the interaction between lifestyle changes and genetic predisposition to these diseases. We compared the prevalences of type 2 diabetes and obesity in Mexican Pima Indians, presumed to have a high genetic predisposition to these diseases, to those in their non-Pima neighbors, both of whom over a 15-year period experienced a transition from a traditional to a more modern lifestyle.RESEARCH DESIGN AND METHODSPrevalence of diabetes, impaired fasting glucose, impaired glucose tolerance, and obesity in Mexican Pimas (n = 359) and non-Pima Mexicans (n = 251) were determined in 2010 using methods identical to those used in 1995.RESULTSDuring this 15-year period, age-adjusted diabetes prevalence was unchanged in Pima men (5.8% in 1995 vs. 6.1% in 2010) yet increased in non-Pima men from 0.0 to 8.6% (P < 0.05). Diabetes prevalence tended to increase in both Pima women (9.4 vs. 13.4%) and non-Pima women (4.8 vs. 9.5%). Age-adjusted prevalence of obesity increased significantly in all groups (6.6 vs. 15.7% in Pima men; 8.5 vs. 20.5% in non-Pima men; 18.9. vs 36.3% in Pima women; 29.5 vs. 42.9% in non-Pima women).CONCLUSIONSType 2 diabetes prevalence increased between 1995 and 2010 in non-Pima men, and to a lesser degree in women of both groups, but it did not increase in Pima men. Prevalence of obesity increased among Pimas and non-Pimas of both sexes. These changes occurred concomitantly with an environmental transition from a traditional to a more modernized lifestyle.

Body composition and susceptibility to type 2 diabetes: an evolutionary perspective

“…82 Certainly, T2DM risk 332 has a genetic component in this population, but recent studies suggest that chronic under-333 nutrition through the 20 th century elevated their T2DM susceptibility through 334 intergenerational plasticity. 83,84 This scenario is consistent with animal studies, wherechronic under-nutrition over multiple generations causes profound changes in offspring 336 epigenetics, growth and metabolism. 85 Second, malnourished infants are not insulin resistant at birth, but rather acquire this 354 phenotype if they develop overweight from childhood onwards.…”

Diabetes and Obesity—Time Bombs to Be Defused

“…Most of these features identified by Popkin (11) were evident to EsparzaRomero et al (3) in their discussion of the basis for the increases in obesity and diabetes in Maycoba. To provide a "quantitative" estimate of the impacts of modern society on this population, they used a "modernization index" consisting of ownership of such items as a refrigerator, telephone, television, car, washer, cell phone, iron, DVD player, mixer, furnace, fan, electricity, Internet, solar panels, and radio.…”

“…In the intervening 17 years, it has risen to 33.5% in men and 36.1% in womend clearly in the wrong direction (2). After reading the article by Esparza-Romero et al (3), I would expand the title of this earlier commentary to say that both obesity and diabetes are time bombs to be defused and that nothing much has happened in the past 17 years to prevent these bombs from exploding.…”

“…The article by Esparza-Romero et al (3) nicely shows the impact of the nutrition transition on the Pimas and nonPimas living through modernization in northern Mexico. In the modernization of Mexico, a high intake of soft drinks is a likely cause of the deteriorating levels of obesity and dental disease, which has prompted the Mexican government to impose taxes on these beverages (11).…”

“…A relationship between diabetes and obesity was recognized by Joslin nearly 100 years ago (10). In this issue of Diabetes Care, the study by EsparzaRomero et al (3) contributes important new information to this problem from two cross-sectional studies on the prevalence of obesity, prediabetes, and diabetes in Pima Indians and non-Pimas living in Maycoba in Sonora, Mexico, that was undergoing Westernization in lifestyle between 1995 and 2010 while the studies were done.…”