Two independent studies published 12 years apart in the journal Diabetes Care evaluated the possible impact of the environment on the prevalence of obesity and diabetes in Arizona’s Pima Indians, a group with the highest reported prevalence of obesity and non-insulin-dependent diabetes mellitus. Data were collected on a population of Pima ancestry living in a remote mountainous location in northwestern Mexico, living a markedly diﬀerent, “traditional” lifestyle in comparison to the Pima people of Arizona. In the 1994 study, measurements of weight, height, body fat, blood pressure, plasma levels of glucose, cholesterol and HbA1c were obtained in 19 women and 16 men and compared with Pimas of the same sex, age, and diabetes status living in Arizona. The study found that Mexican Pimas were lighter and shorter with lower BMIs and lower plasma total cholesterol levels than Arizona Pimas. Only two women (11%) and one man (6%) had diabetes, contrasting with the expected prevalence of 37% and 54% in female and male Arizona Pimas, respectively. Twelve years later, the 2006 study reﬂected the same: signiﬁcantly lower incidences of obesity and diabetes in the populations living in Mexico and leading a traditional lifestyle. The Mexican Pimas also enjoyed higher levels of physical activity than their U.S. Pima counterparts.
Diabetes Care 1994 Sep; 17(9): 1067-74 (Ravussin et al.)
Diabetes Care 2006 Aug; 29(8): 1866-71 (Schulz et al.)