Mortality experience of Navajos with type 2 diabetes mellitus

We sought to determine the contribution of type 2 diabetes mellitus to mortality in a Navajo population, and to assess the impact of pre-existing coronary heart disease on this relationship.

A cohort of 77 Navajos with type 2 diabetes mellitus and 77 non-diabetic controls matched on age, gender and community of residence were followed for an 18-year period, from 1974 to 1992.

The vital status of 152 of the 154 study subjects was ascertained at 18-year follow-up. There were 30 deaths (39%) in the type 2 diabetes group and 13 (17%) in the control group during the 18-year period which was significantly different in bivariate matched pairs analysis (risk ratio = 3.12, McNemar's chi 2 = 7.76, p < 0.01). Multivariate conditional logistic response models (risk ratio = 3.02, 95% CI 1.21, 7.53) and stratification analysis (McNemar's Summary chi 2 = 8.05, 2 df, p < 0.05), confirmed that survival was significantly different for the two groups, even when controlling for baseline cardiovascular comorbidity and hypertension.

These data describe the mortality impact of the epidemic of type 2 diabetes and cardiovascular disease now accelerating among the Navajo. The significant mortality differences between the diabetes and non-diabetes groups and the continuing rise in prevalence of type 2 diabetes underscore the need for an effective community-based approach to diabetes prevention among the Navajo.