To estimate the prevalence of asthma among youth with types 1 and 2 diabetes and examine associations between asthma and glycemic control.
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.
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.
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.
Comments
T1 diabetes and asthma in children, not a simple equation.
In a large cohort of youth with type 1 and type 2 diabetes (T1DM and T2DM) living in U.S.A., Black and colleagues reported an asthma prevalence > 10% [1]. Differences according to race/ethnicity were detected since a higher proportion of patients with asthma were Black, Hispanic, or Asian/Pacific Islander. In addition, asthmatics were also more likely to have a high body mass index (BMI) and a poor glycemic control (assessed from hemoglobin A1c levels). Associations between asthma, demographic characteristics and glycemic control were predominantly driven by the T1DM group, where poor glycemic control was present mainly in subjects pharmacologically untreated for asthma. Because of this latter observation, it was assumed that the systemic anti- inflammatory activity exerted by asthma medications could influence the complex relationship between airway obstruction, BMI, and glycemic metabolism. However, as suggested by the authors, these associations may be present only in specific patients populations. Indeed, evaluating a cohort of T1DM Italian teenagers (all Caucasians), we found that no one had "actual asthma" (i.e. asthma episodes in the last year), even though 43.7% of them were detected to be sensitized to aeroallergens (40.8%, in the "control" population) and 26.8% reported rhinitis [2]. Moreover, 14.3% of T1DM patients had "lifetime asthma", i.e., asthma episodes during life (16.5%, in the "control" population), but all, except one, had mild intermittent disease (5.8%, in the "control" population) and were treated only occasionally with rescue inhalers and had normal lung function, at time of evaluation. Thus T1DM or its treatment (insulin) might lower the frequency and/or the severity of the clinical manifestations of allergy at lower respiratory level, possibly decreasing bronchial hyperreactivity [2,3]. In addition, Italian teenagers with T1DM had median Hb A1 C levels around 8.3 % (good-intermediate control) and lower BMI values than those calculated in asthmatic population, comparable for age and sex. No differences were detected between the atopic and non atopic subgroups [4]. We further evaluated possible correlation between glycemic control grade and atopy, rhinitis, "lifetime asthma" or BMI, but we did not found any significance. In conclusion, we believe that race/ethnicity and possibly a "Mediterranean" environment" (including diet) could affect the relationship between T1DM and asthma.
References 1. Black MH, Anderson A, Bell RA, Dabelea D, Pihoker C, Saydah S, Seid M, Standiford DA, Waitzfelder B, Marcovina SM, Lawrence JM. Prevalence of asthma and its association with glycemic control among youth with diabetes. Pediatrics. 2011; 128: e839-47. 2. Tosca MA, Villa E, Silvestri M, D'Annunzio G, Pistorio A, Aicardi M, Minicucci L, Lorini R, Rossi GA. Discrepancy between sensitization to inhaled allergens and respiratory symptoms in pediatric patients with type 1 diabetes mellitus. Pediatr Allergy Immunol. 2009 Jun;20(4):385-91. 3. Villa M, Cacciari E, Bernardi F, Cicognani A, Salardi S, Zapulla F. Bronchial reactivity in diabetic patients. Relationship to duration of diabetes and degree of glycemic control. Am J Dis Child 1988: 142: 726-9. 4. Silvestri M, Tosca MA, Ciprandi G, D'Annunzio G, Lorini R, Rossi GA. Re: Body mass index and allergic sensitization in children with asthma or type 1 diabetes. Clin Exp Allergy. 2011 Jul;41(7):1044-5.
Conflict of Interest:
None declared