Beginning in 1979, a random sample was conducted to select participants. Sampling was performed to match the two groups on obesity, thereby enabling an analysis of the ethnic differences in diabetes and cardiovascular risk factors independent of the confounding effects of obesity. For those selected, an interview and medical examination were conducted in a mobile clinic. The interview consisted of a personal and family history of diabetes and cardiovascular risk, knowledge of and attitudes towards cardiovascular risk factors, dietary questionnaire, Rose Angina questionnaire, intermittent claudication questionnaire, and medication history. The medical examination consisted of anthropometric measurements, plasma glucose, plasma insulin, hemoglobin, serum cholesterol, triglyceride, HDL, LDL, and VLDL, genetic markers, blood pressure, skin color and electrocardiogram. It was estimated that 400 diabetics would be available over the four years of the study to permit a Diabetic Recall Examination. The purpose of the Diabetic Recall Examination was to assess possible end-organ complications of diabetes involving the eye, kidney, peripheral and autonomic nervous systems, and the peripheral vascular system. The assessment provided baseline data on diabetics which was used for a prospective incidence study. Beginning in 1989, a prevalence survey of type II diabetes mellitus and cardiovascular risk factors was conducted in a low-income barrio in Mexico City. Information collected on this population included demographic data, socioeconomic status, level of acculturation, medical history, diet, exercise, and smoking. The physical examination included measurements of blood pressure, obesity, body fat distribution, and skin color. The laboratory examination included measurements of lipids and lipoproteins, oral glucose tolerance tests, fasting and post-glucose load insulin concentrations and genetic markers.