EFFECTS OF A TRADITIONAL LIFE-STYLE ON OBESITY IN PIMA-INDIANS

OBJECTIVE- The Pima Indians of Arizona have the highest reported preva lences of obesity and non-insulin-dependent diabetes mellitus (NIDDM). In parallel with abrupt changes in lifestyle, these prevalences in Ar izona Pimas have increased to epidemic proportions during the past dec ades. To assess the possible impact of the environment on the prevalen ces of obesity and NIDDM, data were collected on members of a populati on of Pima ancestry (separation 700-1,000 years ago) living in a remot e mountainous location in northwestern Mexico, with a lifestyle contra sting markedly with that in Arizona. RESEARCH DESIGN AND METHODS- Pima heritage was established by history and by use of Pima language. Meas urements of weight, height, body fat (bioimpedance), blood pressure, p lasma levels of glucose, cholesterol, and HbA(1c) were obtained in 19 women (36 +/- 13 years of age) and 16 men (48 +/- 14 years of age) and compared with sex-, age- and diabetes status-matched Pimas living in Arizona (10 Arizona Pimas for each Mexican Pima). RESULTS- Mexican Pim as were lighter (64.2 +/- 13.9 vs. 90.2 +/- 21.1 kg, P < 0.0001;means +/- SD) and shorter (160 +/- 8 vs. 164 +/- 8 cm, P < 0.01) with lower body mass indexes (24.9 +/- 4.0 vs. 33.4 +/- 7.5 kg/m(2), P < 0.0001) and lower plasma total cholesterol levels (146 +/- 30 vs. 174 +/- 31 m g/dl, P < 0.0001) than Arizona Pimas. Only two women (11%) and one man (6%) had NIDDM, contrasting with the expected prevalences of 37 and 5 4% in female and male Arizona Pimas, respectively. CONCLUSIONS- This p reliminary investigation shows that obesity, and perhaps NIDDM, is les s prevalent among people of Pima heritage living a ''traditional'' lif estyle than among Pimas living in an ''affluent'' environment. These f indings suggest that, despite a similar potential genetic predispositi on to these conditions, a traditional lifestyle, characterized by a di et including less animal fat and more complex carbohydrates and by gre ater energy expenditure in physical labor, may protect against the dev elopment of cardiovascular disease risk factors, obesity, and NIDDM.