Prevalence of asthma and its association with glycemic control among youth with diabetes.

Objective: To estimate the prevalence of asthma among youth with types 1 and 2 diabetes and examine associations between asthma and glycemic control.

Methods: This was a cross-sectional analysis of data from the SEARCH for Diabetes in Youth study, which included youth diagnosed with type 1 (n = 1683) and type 2 (n = 311) diabetes from 2002 through 2005. Asthma status and medications were ascertained from medical records and self-administered questionnaires, and glycemic control was assessed from hemoglobin A1c measured at the study visit.

Results: Prevalence of asthma among all youth with diabetes was 10.9% (95% confidence interval [CI]: 9.6%-12.3%). The prevalence was 10.0% (95% CI: 8.6%-11.4%) among youth with type 1 and 16.1% (95% CI: 12.0%-20.2%) among youth with type 2 diabetes and differed according to race/ethnicity. Among youth with type 1 diabetes, those with asthma had higher mean A1c levels than those without asthma, after adjustment for age, gender, race/ethnicity, and BMI (7.77% vs 7.49%; P = .034). Youth with asthma were more likely to have poor glycemic control, particularly those with type 1 diabetes whose asthma was not treated with pharmacotherapy, although this association was attenuated by adjustment for race/ethnicity.

Conclusions: Prevalence of asthma may be elevated among youth with diabetes relative to the general US population. Among youth with type 1 diabetes, asthma is associated with poor glycemic control, especially if asthma is untreated. Specific asthma medications may decrease systemic inflammation, which underlies the complex relationship between pulmonary function, BMI, and glycemic control among youth with diabetes.