Age of Emergence of Disparities in Asthma Prevalence and Morbidity among US Children.

RATIONALE

Early-life exposures may precipitate asthma, but their contribution to disparities in asthma is less clear.

OBJECTIVE

To elucidate racial, ethnic, and socioeconomic status (SES) disparities in the age trajectory of asthma burden among US children.

METHODS

We analyzed three datasets: (1) 2016-2021 National Children's Health Survey (NCHS) (n=223,551); (2) 2015-2017 Child Asthma Call-Back Survey (ACBS) (n=4,289); and (3) 2018-2019 National Inpatient Sample (NIS) (n=23,713 children with asthma). We examined cumulative asthma prevalence by individual-year of age and children's race and ethnicity or SES (NCHS); mean age at asthma diagnosis by race and ethnicity and SES, unadjusted and adjusted for confounders (ACBS); and asthma hospitalization rates overall and per child with asthma by individual year of age and race and ethnicity (NIS).

RESULTS

Among White children, cumulative asthma prevalence rises gradually through childhood, to 6.6% at age 5 and 16.1% by age 17. Prevalence rises more sharply in early childhood among Black children, reaching 17.6% at age 5 (RR 2.6;95%CI 1.9,3.8), but plateaus after age 9, with a consequent decline in Black-White relative disparities into adolescence. Disparities according to SES follow a similar trajectory, emerging early and subsequently narrowing. Similarly, Black, Hispanic and low-income children with asthma are diagnosed at an earlier age than White (or high-income) children. The asthma hospitalization rate rises in the first years of life among all children, but most rapidly among Black children, with a peak absolute Black-White gap at age 4; the relative gap remains wide throughout childhood and peaks at age 10. However, per child with asthma, relative disparities in White-Black hospitalizations rise through age 15.

CONCLUSIONS

Disparities in asthma prevalence emerge in early childhood and then narrow, suggesting that reducing early-life adverse environmental exposures may be key to asthma prevention. Policies to improve the social determinants of health during gestation and childhood, e.g. environmental equity and family income support, are needed.