35 - Chlorinated pool exposure, atopy, and risk of age 5-year asthma
Sunday, April 24, 2022
3:30 PM – 6:00 PM US MT
Poster Number: 35 Publication Number: 35.300
Elie J. Mitri, Massachusetts General Hospital, Hopkinton, MA, United States; Sabrina Ferhani, Massachusetts General Hospital, Dedham, MA, United States; Jingya Gao, MassGeneral Hospital for Children, Boston, MA, United States; Janice A. Espinola, Massachusetts General Hospital, Boston, MA, United States; Carlos A. Camargo, Massachusetts General Hospital / Harvard University, Boston, MA, United States
Clinical Fellow in Allergy and Immunology Brigham and Women's Hospital Boston, Massachusetts, United States
Background: There is continued uncertainty about the association between early life exposure to chlorinated pools and the development of childhood asthma – especially within a high-risk group of infants hospitalized with bronchiolitis.
Objective: To investigate the association between chlorinated pool exposure in early life (age < 2 years), and the development of age 5-year asthma within a severe bronchiolitis cohort. We also aimed to examine whether this association is modified by the presence of atopy.
Design/Methods: We conducted a multicenter, prospective cohort study of 921 infants hospitalized for bronchiolitis. Follow-up was conducted via biannual parent interviews including questions about cumulative pool attendance (CPA). Early life chlorinated pool exposure was defined as total hours from birth until age 2 years. Exposure duration was categorized as: 0 hours CPA, >0-20 hours CPA, and >20 hours CPA. We defined age 5-year asthma as clinician-diagnosed asthma by age 5 years and either asthma medication use or symptoms during the age of 4-4.9 years. We defined infant atopy as total IgE of >100 IU/L or any positive serum specific IgE to food or aeroallergens during infancy. All participants had blood IgE levels measured during infancy.
Results: Among 817 (89%) children with complete exposure and outcome data, 539 (66%) reported going to a chlorinated pool by age 2 years; 413 (51%) had a CPA of < 0-20 hours and 126 (15%) had a CPA of >20 hours during the first two years of life. Overall, 228 (28%) children developed asthma by age 5 years. Using multivariable logistic regression, we did not detect an association between total CPA during early life and asthma (P>0.30 for both CPA >0-20 hours and >20 hours compared to no exposure). However, in sensitivity analyses separating indoor and outdoor pool exposure, we found that those with >20 hours of indoor CPA during early life had a potential higher odds of developing asthma (adjusted odds ratio 2.27; 95% confidence interval 0.90–5.74; P=0.08). We did not detect effect modification between atopy and >20 hours of total CPA exposure (P interaction=0.28), nor between atopy and >20 hours of indoor CPA exposure (P interaction=0.24), but interaction analyses were limited by small numbers.Conclusion(s): In a severe bronchiolitis cohort, total chlorinated pool exposure during early life was not associated with increased risk of age 5-year asthma. However, in sensitivity analyses looking at indoor pool CPA, we did observe a possible two-fold increased risk of asthma. TABLE I. Cohort characteristics and pool exposure status from birth until 2 yearsAbbreviations: CPA, cumulative pool attendance; IgE, immunoglobulin E; sIgE, serum specific-IgE; RSV, Respiratory Syncytial Virus. Results reported as n (%) unless otherwise noted. TABLE II. Multivariable logistic regression models for the association between chlorinated pool exposure from birth until age 2 years and age 5-year asthmaAbbreviations: aOR, adjusted odds ratio; CI, confidence interval; CPA, cumulative pool attendance.
* Models adjusted for age at enrollment, sex, premature birth, race/ethnicity, virus at index hospitalization, median household income by ZIP code, child history of eczema, parental history of allergic disease, passive smoking exposure, maternal smoking during pregnancy, breastfeeding, daycare attendance, and number of siblings