Case-control study of exclusive breast feeding and severe bronchiolitis in the United States.

BACKGROUND: Bronchiolitis is a major cause of infant illness, with few known modifiable risk factors. Breast feeding may reduce risk of severe bronchiolitis, but the association of exclusive vs. partial breast feeding with severe bronchiolitis is unclear. OBJECTIVE: To estimate the association of exclusive vs. partial breast feeding during ages 0-2.9 months with bronchiolitis hospitalisation during infancy. METHODS: We conducted a case-control study as a secondary analysis of two prospective US cohorts in the Multicenter Airway Research Collaboration. Cases were enrolled in a 17-centre study of infants hospitalised for bronchiolitis during 2011-2014 (n = 921). Controls were enrolled in a five-centre study of healthy infants during 2013-2014 and 2017 (n = 719). Breast feeding history during ages 0-2.9 months was collected by parent interview. Among breastfed infants, the association of exclusive vs. partial breast feeding with odds of bronchiolitis hospitalisation was estimated using a multivariable logistic regression model adjusted for demographic variables, parental asthma history, and early-life exposures. As a secondary analysis, we estimated the associations of exclusive, predominant, and occasional breast feeding vs. no breast feeding with the odds of bronchiolitis hospitalisation. RESULTS: Among 1640 infants, the prevalence of exclusive breast feeding was 187/921 (20.3%) among cases and 275/719 (38.3%) among controls. Exclusive vs. partial breast feeding was associated with 48% reduced odds of bronchiolitis hospitalisation (adjusted odds ratio [OR] 0.52, 95% confidence interval [CI] 0.39, 0.69). In the secondary analysis, exclusive vs. no breast feeding was associated with 58% reduced odds of bronchiolitis hospitalisation (OR 0.42, 95% CI 0.23, 0.77), whereas predominant breast feeding (OR 0.77, 95% CI 0.37, 1.57) and occasional breast feeding (OR 0.98, 95% CI 0.57, 1.69) were not associated with meaningfully reduced odds of bronchiolitis hospitalisation. CONCLUSION: Exclusive breast feeding had a strong protective association against bronchiolitis hospitalisation.

Late Pre-term Infants with Severe Bronchiolitis and Risk of Asthma by Age 5 Years.

In a prospective, multicenter cohort of infants hospitalized with bronchiolitis, we found infants born late pre-term (ie, gestational age of 34-36.9 weeks) had 35% higher odds of having asthma by age 5 years compared with infants born at full-term.

Factors associated with mild bronchiolitis in young infants.

Objective: Bronchiolitis within the first 3 months of life is a risk factor for more severe illness. We aimed to identify characteristics associated with mild bronchiolitis in infants ≤90 days old presenting to the emergency department (ED). Methods: We conducted a secondary analysis of infants ≤90 days old with clinically diagnosed bronchiolitis using data from the 25th Multicenter Airway Research Collaboration prospective cohort study. We excluded infants with direct intensive care unit admissions. Mild bronchiolitis was defined as (1) sent home after the index ED visit and did not have a return ED visit or had a return ED visit without hospitalization, or (2) were hospitalized from the index ED visit to the inpatient floor for <24 hours. Multivariable logistic regression, adjusting for potential clustering by hospital site, was used to identify factors associated with mild bronchiolitis. Results: Of 373 infants aged ≤90 days, 333 were eligible for analysis. Of these, 155 (47%) infants had mild bronchiolitis, and none required mechanical ventilation. Adjusting for infant characteristics, clinical factors associated with mild bronchiolitis included older age (61-90 days vs 0-60 days) (odds ratio [OR] 2.72, 95% confidence interval [CI] 1.52-4.87), adequate oral intake (OR 4.48, 95% CI 2.08-9.66), and lowest ED oxygen saturation ≥94% (OR 3.12, 95% CI 1.55-6.30). Conclusions: Among infants aged ≤90 days presenting to the ED with bronchiolitis, about half had mild bronchiolitis. Mild illness was associated with older age (61-90 days), adequate oral intake, and oxygen saturation ≥94%. These predictors may help in the development of strategies to limit unnecessary hospitalization in young infants with bronchiolitis.

Parental Mental Health and Childhood Respiratory Outcomes in a Severe Bronchiolitis Cohort.

Parental mental health conditions appear to contribute to the development of childhood respiratory illness. We investigated the relationship between parental mental health and childhood respiratory illness using data from a 17-center prospective cohort study of infants hospitalized with bronchiolitis between 2011 and 2014 (n = 921). Among 779 (84.6%) participants with self-reported parental mental health history data, 184 (23.6%) had parental history of depression and 155 (19.9%) had anxiety. Multivariable analyses found that both parental history of depression (hazard ratio [HR] 1.41, 95% confidence interval [CI] 1.01-1.99) and anxiety (HR 1.28, 95% CI 1.08-1.52) were associated with an increased risk of recurrent wheezing by age 3 years. However, only parental history of anxiety was associated with asthma by age 5 years (odds ratio 1.79, 95% CI 1.25-2.55). Further research on exposure severity, other early life stressors, and effective methods of parental psychosocial support is needed to develop targeted risk factor prevention strategies to reduce the burden of childhood respiratory illness.

Infant Exposure to Acid Suppressant Medications Increases Risk of Recurrent Wheeze and Asthma in Childhood.

BACKGROUND: Acid suppressant medications (ASMs) are commonly prescribed in infancy. Little is known about the relationship between ASM exposure and risk of childhood asthma and atopic conditions. OBJECTIVE: We sought to examine the association between infant ASM exposure and risk for developing recurrent wheeze, allergen sensitization, and asthma in early childhood. METHODS: We used data from a diverse, multicenter, prospective cohort study of 921 infants with a history of bronchiolitis. ASM exposure (histamine-2 receptor antagonists and/or proton pump inhibitors) during infancy (age: <12 months) was ascertained by parent report and medical record review. The outcomes were recurrent wheeze by age 3 years, early childhood allergen sensitization (serum specific IgE), and asthma by age 6 years. We constructed multivariable Cox proportional hazards models and multivariable logistic regression models adjusting for multiple confounders. RESULTS: Of the 921 children in the cohort, 202 (22%) were exposed to ASMs during infancy. Compared with unexposed children, those exposed to ASM were more likely to develop recurrent wheeze by age 3 years (adjusted hazard ratio: 1.58, 95% confidence interval [CI]: 1.20-2.08, P = .001) and asthma by age 6 years (adjusted odds ratio: 1.66, 95% CI: 1.22-2.27, P = .001). ASM exposure during infancy was not significantly associated with the development of early childhood allergen sensitization (adjusted odds ratio: 1.00, 95% CI: 0.70-1.44, P = .99). CONCLUSIONS: Although exposure to ASMs during infancy does not increase the risk of allergen sensitization in early childhood, ASM exposure during infancy increases the risk of recurrent wheeze and asthma during early childhood.

Association of Growth Trajectory Profiles with Asthma Development in Infants Hospitalized with Bronchiolitis.

BACKGROUND: Little is known about the relationship of longitudinal growth trajectory in early life with asthma development, particularly in infants with bronchiolitis (a high-risk population). OBJECTIVE: Among infants with bronchiolitis, we aimed to identify growth trajectory profiles and determine their longitudinal relationship with the risk for developing childhood asthma. METHODS: A multicenter prospective study enrolled infants (aged <1 year) hospitalized for bronchiolitis. We identified growth trajectory profiles-derived from body mass index-for-age at ages 0, 6, 12, 15, 18, 24, and 36 months by using a longitudinal clustering method. We examined associations between growth trajectory profiles and asthma development by age 5 years. RESULTS: The analytic cohort consists of 880 infants hospitalized for bronchiolitis (median age, 3 months). Overall, 26% developed asthma by age 5 years. The longitudinal clustering identified 5 distinct profiles: persistent low growth (27%), normative growth (33%), transient overweight (21%), late-onset overweight (16%), and persistent obesity (3%) profiles. In multivariable model, compared with children with a normative profile, those with a persistent obesity profile had significantly higher risks of developing asthma (24% vs 38%, odds ratio [OR]: 2.55, 95% confidence interval [CI]: 1.07-6.09, P = .03). Among children with a persistent obesity profile, those without allergic predisposition had significantly higher risks of asthma (OR: 3.02, 95% CI: 1.05-8.64, P = .04 in the nonparental allergic history group; OR: 3.18, 95% CI: 1.02-9.92, P = .047 in the non-IgE sensitization group), whereas those with allergic predisposition were not at increased risk. CONCLUSIONS: This multicenter cohort study of infants with bronchiolitis demonstrated distinct growth trajectory profiles that have differential risks for developing asthma.

Proximity to Major Roads and Risks of Childhood Recurrent Wheeze and Asthma in a Severe Bronchiolitis Cohort.

Air pollution exposures have been suggested as risk factors for childhood respiratory diseases. We investigated proximity to major roads, an indicator of air pollution exposure, and its associations with childhood recurrent wheeze and asthma. We used data from a multicenter prospective cohort study of 921 infants hospitalized for bronchiolitis and recruited from 14 U.S. states. Primary exposure was residential proximity to the nearest major road at birth through age 3 years. Residential distance from nearest major road was divided into four categories: <100, 100-200, 201-300, and >300 m. Outcomes were parent-reported recurrent wheeze by age 3 years and asthma by age 5 years. Associations between residential proximity to major roads and respiratory outcomes were investigated using multivariable Cox proportional hazards modeling and logistic regression, adjusted for confounders. Out of 920 participants with home address data, pooled estimates identified 241 (26%) participants resided within 300 m of a major road, 296 (32%) developed recurrent wheeze by age 3, and 235 out of 858 participants (27%) developed asthma by 5 years. Participants who resided close to a major road had the highest risk of recurrent wheeze (adjusted hazards ratio for <100 m, 1.59, 95%CI: 1.08-2.33) and asthma (adjusted odds ratio for 201-300 m, 1.62, 95%CI: 1.16-2.25), compared to those residing >300 m from a major road. Proximity to major roads is associated with increased risks of recurrent wheeze and asthma in young children.