The Impact of Long-Term Air Pollution Exposure on Type 1 Diabetes Mellitus-Related Mortality among U.S. Medicare Beneficiaries

Background: Little of the previous literature has investigated associations between air pollution exposure and type 1 diabetes mellitus (T1DM)-related mortality, despite a well-established link between air pollution exposure and other autoimmune diseases. Methods: In a cohort of 53 million Medicare beneficiaries living across the conterminous United States, we used Cox proportional hazard models to assess the association of long-term PM(2.5) and NO(2) exposures on T1DM-related mortality from 2000 to 2008. Models included strata for age, sex, race, and ZIP code and controlled for neighborhood socioeconomic status (SES); we additionally investigated associations in two-pollutant models, and whether associations were modified by participant demographics. Results: A 10 μg/m(3) increase in 12-month average PM(2.5) (HR: 1.183; 95% CI: 1.037–1.349) and a 10 ppb increase in NO(2) (HR: 1.248; 95% CI: 1.089–1.431) was associated with an increased risk of T1DM-related mortality in age-, sex-, race-, ZIP code-, and SES-adjusted models. Associations for both pollutants were consistently stronger among Black (PM(2.5): HR:1.877, 95% CI: 1.386–2.542; NO(2): HR: 1.586, 95% CI: 1.258–2.001) and female (PM(2.5): HR:1.297, 95% CI: 1.101–1.529; NO(2): HR: 1.390, 95% CI: 1.187–1.627) beneficiaries. Conclusions: Long-term NO(2) and, to a lesser extent, PM(2.5) exposure is associated with statistically significant elevations in T1DM-related mortality risk.