Background: Asthma, a chronic respiratory condition affecting 8.2% of the US population (2009), causes significant societal and economic burden, resulting in missed school/work days, activity limitations, and increased healthcare utilization. Annual asthma prevalence estimates are available from national surveys, but these surveys have not routinely collected asthma incidence data that are important for identifying risk factors and trends in rates of disease onset. The Asthma Call-back Survey (ACBS), implemented in 2006, provides detailed asthma data that supplement Behavioral Risk Factor Surveillance System (BRFSS) data. We analyzed BRFSS and ACBS data to estimate annual asthma incidence and to determine whether these rates differed by age group, sex, and race/ethnicity.
Methods: BRFSS and ACBS data from the participating states during 2006-2008 (24 states and District of Columbia [DC] in 2006; 34 states and DC in 2007 and 2008) were analyzed to calculate 12-month incidence rates. Incident cases of asthma were defined as people diagnosed with asthma by a healthcare provider within 12 months prior to survey participation.
Results: Estimated asthma incidence among at-risk adults was 3.8/1000, whereas that among at-risk children was 12.5/1000. Incidence among children aged 0-4 years was 23.4/1000, more than five times greater than that among youth aged 12-17 years (4.4/1000). Adult females had 1.8 times greater asthma incidence than adult males (4.9/1000 vs. 2.8/1000, respectively). Incidence among non-Hispanic (NH) White adults was 3.9/1000, among NH non-White adults was 3.2/1000, and among Hispanic adults was 4.0/1000.
Conclusions: This is the first successful application of the BRFSS-ACBS during 2006-2008 to estimate asthma incidence rates from participating states and DC. As with known patterns in asthma prevalence, we found that asthma incidence was higher in children than adults, higher in younger children than older children and adolescents, and higher in adult females than adult males. However, we were unable to identify statistically significant differences in asthma incidence among most race/ethnic groups. As additional data on asthma incidence become available from the ACBS, these rates, coupled with ACBS data on symptoms, asthma self-management practices, and healthcare utilization, may help asthma control programs identify risk factors for disease development and target asthma prevention and control measures to populations most affected.