Asthma Incidence in Childhood: The Impact of the Neighborhood
—Youngsters who live in areas of the U.S. where opportunity is high or very high during early life—and vulnerability to factors like poverty, crowding, or natural disasters is low—may have decreased rates of childhood asthma, say the investigators behind a new study.
Where a child lives may have a lot to do with whether or not he or she develops asthma early in life. In fact, according to a new study, a lower incidence of asthma in childhood is indeed associated with residence in neighborhoods with high or very high levels of opportunity, compared with disadvantaged neighborhoods.1
Not all of this is new knowledge. Neighborhood factors have been shown to contribute to health risks and outcomes in certain social and physical environments.2 However, it’s unclear the extent to which these conditions are associated with incidence of asthma at birth or early childhood. Neighborhood indices derived from census data, including the Social Vulnerability Index (SVI) and the Child Opportunity Index (COI), are composite measures thought to be more meaningful than individual socioeconomic measures.3,4
“The extent to which both indices may be related to childhood asthma incidence and whether they are equally or differentially predictive remain understudied,” lead author Izzuddin M. Aris, PhD, Department of Population Medicine, Harvard Medical School and Harvard Pilgrim Health Care Institute, Boston, and his colleagues noted in JAMA Pediatrics.1 “To address these research gaps, we analyzed data from racially, ethnically, and geographically diverse children enrolled in cohorts participating in the Environmental Influences on Child Health Outcomes (ECHO) Program,5 which includes repeated measures of residential addresses across distinct child life stages and parent or caregiver report[s] of physician-diagnosed asthma.”1
Study design and patient population
This study used data from 46 cohorts, including 10,516 children, from the ECHO Program, recorded between January 1, 1995, and August 31, 2022. Participants had physician-diagnosed asthma based on reports from caregivers or parents, and 1 or more high-quality geocoded residential address from birth. The median age at follow-up was 9.1 years, and 47.8% of the children were female. In terms of race/ethnicity, 85.0% were non-Hispanic and 65.3% were White.
Approximately 20% of children resided in neighborhoods with very low SVI and very high COI. Negative correlations were observed between SVI and COI at birth, infancy, and early childhood. There were strong correlations for COI at birth and infancy, infancy and early childhood, and birth and early childhood. The overall asthma incidence rate was 23.3 cases per 1000 child-years, and the median age at diagnosis was 6.6 years.
Evaluating asthma incidence rates
There were lower crude asthma incidence rates in areas with higher opportunities. Moderate, high, and very high COI at birth were associated with a lower incidence of asthma after adjusting for number of births (parity), parental asthma history, and sociodemographic characteristics. Low, high, and very high COI were associated with a lower incidence of asthma in infancy and early childhood after adjusting for these same covariates.
Crude asthma incidence rates were lower in areas with lower social vulnerability, though there were no significant associations between SVI and asthma incidence at birth, infancy, or early childhood, again after adjusting for parity, parental asthma history, and sociodemographic characteristics. The adjusted incidence rate ratios for asthma were 0.88 and 0.89 for low and very low SVI at birth, respectively.
“The association of very high COI at each life stage with lower asthma incidence appeared to be attributable to the health and environmental and the social and economic domains but not the education domain,” Dr. Aris and his colleagues explained in JAMA Pediatrics. “No significant associations were observed between each SVI domain and asthma incidence. No evidence of modification of associations by child sex, race and ethnicity, or rurality of residence was observed.”1
What are the main take-aways?
In this cohort study, Dr. Aris and his colleagues revealed an association between residence in neighborhoods with high and very high levels of opportunity in early life and lower incidence of asthma in childhood.
According to the authors, “Our findings highlight the need for future studies examining whether investing in health and environmental or social and economic resources in early life promotes health equity in pediatric asthma.”1
Limitations of this study include its reliance on a parent or caregiver report of an asthma diagnosis; use of residential census tracts as an exposure marker, which may not reflect areas where kids spend most of their time; the concentration of many cohorts in the eastern and western U.S.; and the lack of consideration of the impact of “residential mobility” from birth to early childhood.
“Given the long-term association of childhood asthma with adult health, additional research is warranted to investigate whether strategies that alter specific neighborhood components would be effective in preventing childhood asthma,” the authors concluded.1
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