Objective: We sought to assess the long-term trends in the incidence of type 1 diabetes among non-Hispanic white and Hispanic youth aged 0-17 years from Colorado using data from the Colorado IDDM Study Registry (1978-1988) and SEARCH for Diabetes in Youth (2002-2004).
Research design and methods: Cases of diabetes were ascertained through physician reporting and hospital databases. Type 1 diabetes was defined as use of insulin within 2 weeks from diagnosis. Completeness of ascertainment was estimated as 97%. Annual average incidence rates (per 100,000/year) and 95% CIs for the time periods were computed. Trends in incidence were assessed by Poisson regression.
Results: The incidence of type 1 diabetes was 14.8 (95% CI 14.0-15.6) in 1978-1988 and 23.9 (22.2-25.6) in 2002-2004 for the state of Colorado (P < 0.0001). From 1978 to 2004, the incidence of type 1 diabetes increased by 2.3% (1.6-3.1) per year (P < 0.0001). The increase in incidence was significant for both non-Hispanic white (2.7% [95% CI 1.9-3.6] per year, P < 0.0001) and Hispanic youth (1.6% [0.2-3.1] per year, P = 0.013).
Conclusions: The incidence of type 1 diabetes has increased 1.6-fold among Colorado youth from 1978-1988 to 2002-2004, and both non-Hispanic white and Hispanic youth are affected by this trend.