Association of socioeconomic status with mortality in type 1 diabetes: the Pittsburgh epidemiology of diabetes complications study.

PURPOSE

Socioeconomic status (SES) as a risk factor for mortality in type 1 diabetes (T1D) has not been adequately studied prospectively.

METHODS

Complete clinical and SES (income, education, occupation) data were available for 317 T1D participants in the Pittsburgh Epidemiology of Diabetes Complications Study within 4 years of age 28 (chosen to maximize income, education, and occupational potential, and to minimize the SES effect of advanced diabetes complications). Vital status was determined as of 1/1/2008.

RESULTS

Over a median 16 years of follow-up, 34 (10.7%) deaths occurred (standardized mortality ratios [SMRs] = 4.1, 95% confidence interval [CI]: 2.7-5.5). SMRs did not differ from the general population for those in the highest education and income groups, whereas in those with low SES, SMRs were increased. Mortality rates were three times lower for individuals with a college degree versus without a college degree (p = 0.004) and nearly four times lower for the highest income versus lower income groups (p = 0.04). In Cox models adjusting for diabetes duration and sex, education was the only SES measure predictive of mortality (hazard ratio [HR] = 3.0, 95% CI: 1.2-7.8), but lost significance after adjusting for HbA(1c), non-HDL cholesterol, hypertension, and microalbuminuria (HR = 2.1, 95% CI: 0.8-5.6).

CONCLUSIONS

The strong association of education with mortality in T1D is partially mediated by better glycemic, lipid, and blood pressure control.