Prospective Study of Diabetes-Related Vascular Disease in Oklahoma Indians

BACKGROUND:

Diabetes is a major health hazard in Oklahoma Indians. A further important aspect is the apparently high vulnerability of the diabetic Oklahoma Indians to atherosclerotic disease. In the mid 1980s, this group had the highest prevalence of 0-wave changes on the electrocardiogram and amputation for ischemic gangrene of all 14 international samples in the World Health Organization Multinational Study. Its cardiovascular mortality rates were 2-3 times those of other national samples. An epidemic of coronary heart disease was attacking this Indian population.

Between 1973 and 1978, 1,085 adult Oklahoma Indians who were diagnosed with non-insulin dependent diabetes mellitus were recruited for a study on diabetes. The data from the study were used in part for the World Health Organization Multinational Study of Vascular Disease in Diabetes. The subjects were given a complete physical examination which included blood pressure, height, weight, electrocardiogram and detailed eye examination. Data were also collected on plasma cholesterol, plasma triglyceride, and proteinuria. Family histories and body weight were reviewed. The study followed this cohort.

DESIGN NARRATIVE:

This longitudinal study followed a previously studied cohort. Detailed baseline data collected in 1973-1978 were available. In phase I of the study, the life/death status of all 1,085 subjects was ascertained up to January 1, 1986. Death certificates were obtained and cause of death analyzed. For the survivors, a personal interview and physical examination were performed in Phase II. Occurrence of specified diabetes-related vascular complications was documented. The detailed follow-up questionnaire included all the data required for the WHO Multinational Study of Vascular Disease in Diabetes plus specific information related to this population. Analysis was conducted on overall mortality rates, disease-specific mortality rates, and survival time. Prevalence and incidence of morbidity from micro- and macrovascular complications were estimated. The extent to which selected risk factors were associated with or could predict the development of vascular diseases was examined. The results of the analyses were compared with those obtained in the WHO Multinational Study.