The overall incident rate (IR) of asthma with recurrent exacerbations (ARE) among US children is 6.07/1000 person-years but varies by age, race/ethnicity, sex, region, parental history, and time period studied, according to study findings published in the Journal of Allergy and Clinical Immunology.
Previous studies have shown that asthma IRs in the US are associated with defined time periods as well as an individual’s age, race/ethnicity, parental history of asthma, and birthplace. Investigators aimed to determine if these same factors would influence IRs for recurrent exacerbations in US children and adolescents.
The investigators conducted a retrospective observational study, estimating IRs for ARE using data from Environmental Influences on Child Health Outcomes (ECHO) consortium for 17,246 children who met study eligibility criteria; these children were from cohorts in 59 states and Puerto Rico. The ECHO consortium, a US nationwide research platform combining extant and prospectively collected data, included children born from 1990 to 2017 who were followed through 20 years of age. Data used for the current study included information on clinician-diagnosed asthma, date of diagnosis, and corticosteroid use, which were collected from birth through the end of follow-up or through the end of the study period in August 2022.
An ARE outcome was determined when a child had 2 or more reports of systemic corticosteroid use at any time during follow-up but at least 30 days apart. For the current analysis, children also had to have a health care provider diagnosis of asthma during follow-up.
The investigators found that 4114 children in ECHO were ever diagnosed with asthma. Of these, 2061 had at least 1 asthma exacerbation and 734 children had at least 2 exacerbations.
The investigators noted higher adjusted ARE IRs (aIRR) for children born 2000 to 2009 vs children born 1990 to 1999 (aIRR, 1.62/1000 person-years; 95% CI, 1.13-2.32; P <.01) and higher aIRRs for those born 2000 to 2009 vs children born 2010 to 2017 (aIRR, 2.12; 95% CI, 1.77-2.53; P-value not given) in multi-variable analysis. Children born in 2010 to 2017 compared with children born 1990 to 1999 had a statistically nonsignificant lower aIRR (0.76; 95% CI, 0.54-1.08; P =.13).
The investigators found higher aIRRs for children 2 to 4 years of age vs those 10 to 19 years of age (aIRR, 15.36; 95% CI, 12.09-19.52; P <.01) and for children 5 to 9 years of age vs those 10 to 19 years of age (aIRR, 3.69; 95% CI, 2.89-4.70). They noted higher aIRRs for boys vs girls (aIRR, 1.34; 95% CI, 1.16-1.55; P <.01). Black children (Hispanic and non-Hispanic) had higher aIRRs vs White children (aIRR, 2.04; 95% CI, 1.22-3.39 and aIRR, 2.51; 95% CI, 2.10-2.99, respectively).
Children born in the Northeast, South, and Midwest had higher aIRRs vs children born in the West (P <.01 for each comparison). In children with at least 1 parent with a history of asthma, aIRRs were nearly 3 times higher than in children whose parents had no history of asthma (aIRR, 2.90; 95% CI, 2.43-3.46; P <.01).
The researchers noted the overall crude IR for AREs was 6.07/1000 person-years (95% CI, 5.63-6.51). ARE IRs were higher for children 2 to 4 years of age in each race and ethnicity category and for both sexes. The percentage distribution of the ECHO population varied over time with respect to race and ethnicity and geographic region.
Study limitations included the harmonizing of data for systemic corticosteroid use; the use of broad and politically defined geographic categories; the fact that ECHO participants are not representative of US children or pediatric patients; underpowered sample sizes for some analyses; and variance in prescribing patterns for systemic corticosteroids.
“The importance of time of surveillance, decade of birth, very young age, race and ethnicity, and census region detected here all suggest substantial impacts of environment exposures that may change over time in the etiology of ARE,” investigators concluded. “The susceptibility to ARE especially during the younger ages suggests that risk factors such as genetic predisposition as well as environmental exposures that are more prominent during young ages (e.g. respiratory viruses, those related to acculturation, other early lifestyle preferences) may be influential,” noted study authors.
Disclosure: Some study authors declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of authors’ disclosures.
Miller RL, Schuh H, Chandran A, et al.; program collaborators for Environmental influences on Child Health Outcomes. Incidence rates of childhood asthma with recurrent exacerbations in the U.S. Environmental influences on Child Health Outcomes (ECHO) program. J Allergy Clin Immunol. Published online March 25, 2023. doi:10.1016/j.jaci.2023.03.016