Asthma may contribute to poor glycemic control in young people with diabetes, especially if it is kept untreated, according to results from a study of nearly 2000 children and adolescents, age 20 years and younger, with either type 1 or type 2 diabetes.

Researchers have recently come to suspect that obesity may be associated with systemic inflammation, with some studies suggesting links between impaired lung function and elevated glucose levels. Those studies have also shown that people with diabetes often have poorer lung function than normal control patients.

To find out more about the link between diabetes and lung function, Dr. Black and colleagues conducted a cross-sectional analysis of data from the SEARCH for Diabetes in Youth Study. SEARCH is an on-going large observational study focusing on a diverse population of children and adolescents with both type 1 and type 2 diabetes.

Dr. Black's group looked at SEARCH data on 1683 youths diagnosed with type 1 diabetes and 311 youths diagnosed with type 2 diabetes during the period from 2002 to 2005.

Several factors were associated with the dual diagnoses of asthma and diabetes: older age; male sex; black, Hispanic, or Pacific Islander ethnicity; and residing in a single-parent household.

Youths with dual diagnoses of type 1 diabetes and asthma had higher mean A1c levels than those with diabetes alone. That was true even after adjustment for age, sex, race/ethnicity, and body mass index (7.77% vs 7.49%; P = .034), the authors say.