Infant Asthma

RISK FACTORS FOR INFANT ASTHMA IN SUSCEPTIBLE FAMILIES Center for Research on Child Wellbeing Working Paper # 2007-15-FF

Bill Chiu1, MD Marie Crandall1, MD, MPH Karen Sheehan2, MD, MPH Departments of Surgery1 and Pediatrics2 Northwestern University Feinberg School of Medicine

Corresponding Author: Marie Crandall, MD, MPH Assistant Professor of Surgery Division of Trauma and Surgical Critical Care Northwestern University 201 E. Huron St., Galter #10-105 Chicago, IL 60611 Telephone: 312-695-4835 Fax: 312-695-1462 E-Mail: [email protected]

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Infant Asthma

RISK FACTORS FOR INFANT ASTHMA IN SUSCEPTIBLE FAMILIES

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Infant Asthma

ABSTRACT Purpose: Socioeconomically disadvantaged communities in the United States have disproportionately high number of children diagnosed with asthma. We investigated risk factors contributing to the disease among children born to susceptible families.

Methods: The Fragile Families and Child Wellbeing Study is a longitudinal cohort of approximately 5000 children from disadvantaged parents across the United States. Data from interviews with mothers conducted shortly after birth and follow-up surveys at one year were analyzed. Infant asthma requiring medical attention was the outcome of interest. Multivariate regression analysis identified independent risk factors for infant asthma.

Results: 13.5% of the respondents (n=506 of 3747) had an infant with asthma. Significant risk factors included maternal cigarette smoking, low birth weight, infant male gender, and African American race. Breastfeeding was protective.

Conclusion: Environmental factors interact with a child’s characteristics in contributing to infant asthma. Policies that promote breastfeeding and discourage maternal cigarette smoking could reduce asthma incidence.

Key Words: Infancy, asthma, racial disparities, smoking

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Infant Asthma

Approximately 17.3 million people in the United States are estimated to have asthma1, and one third of these affected are children2. The prevalence of asthma is particularly high in urban, minority, and low-socioeconomic populations, and the rates have been rising3. Despite many studies that report the overrepresentation of asthmatics in vulnerable populations4, which risk factors can independently predict asthma diagnosis still remain to be determined. In this study, we analyze a prospectively gathered database containing interview responses from a vulnerable population. By examining how different risk factors can affect a predominantly low-socioeconomic group, we aim to identify intervention strategies that can decrease the incidence of asthma in this overburden population.

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Infant Asthma

METHODS Data for this research was obtained from the Fragile Families and Child Wellbeing study. Fragile Families is a longitudinal study following approximately 5000 children nationwide born between 1998 and 2000, the majority from unmarried households. Permission to use this database was granted from the Fragile Families Collaborative, and the Northwestern University Institutional Review Board approval was obtained. Data were analyzed using STATA statistical software (© Stata Press, College Station, TX). Data from baseline interviews with the mother and follow-up interviews at one year were utilized. The outcome of interest, asthma requiring medical attention in the first year of life, was identified through self-report during the maternal follow-up interviews. The three questions were (1) whether mother was told by health care professional that child has asthma, (2) whether child ever had an episode of asthma attack, and (3) whether child was treated for asthma at a hospital emergency room. Responses to these three questions were combined to represent the outcome in our analysis. Potential risk factors for asthma were listed in Table 1A. Bivariate analyses between the individual risk factors and the asthma outcome were performed using χ2 tests. Variables were identified as potential independent predictors of asthma or confounders by using sequential multiple regression models which included variables that yielded a p-value≤0.1 on bivariate statistics. This final multivariate regression model was used to identify independent risk factors for asthma in the first year of life. A p-value