Phipatanakul, WandaAKINBOLAGBE, YESIDE2026-05-0420262026-05-042026AKINBOLAGBE, YESIDE. 2026. EFFECT OF RADON DECAY PRODUCT EXPOSURE ON ASTHMA MORBIDITY IN STUDENTS WITH ASTHMA and THE IMPACT OF RADON ON LUNG HEALTH IN SCHOOL-AGED CHILDREN WITH BRONCHOPULMONARY DYSPLASIA . Masters Thesis, Harvard Medical School.32678083https://dash.harvard.edu/handle/1/42736463Paper 1 Importance: Exposure to indoor air pollutants has been shown to be associated with asthma development and morbidity, however, the effect of radon decay products on asthma is unknown. Objective: To determine if direct exposure to radon-derived  and -particle radioactivity would be associated with increased asthma morbidity in school-aged children. Design: Longitudinal cohort study conducted in children (ages 4–14 years) with persistent asthma in the School Inner-City Asthma Study (SICAS), from 2008–2013 (SICAS-1) and 2015-2020 (SICAS-2). SICAS-1 was a prospective longitudinal cohort designed to evaluate how school/classroom environmental exposures relate to asthma morbidity among children with asthma attending inner-city metropolitan schools. SICAS-2 was a cluster-randomized, placebo-controlled trial of the effects of classroom-level HEPA purifiers and school-level integrated pest management on asthma morbidity. Setting: Inner-city schools in the northeast United States. Participants: 294 schoolchildren, aged 4-14 years with asthma enrolled in the School Inner-City Asthma Study were included. Exposure: Exposure (radon decay product) was quantified by direct measurement of particulate matter (PM2.5)  and -emitting particle radioactivity (PR) extracted from dust samples collected from particle sampler filters. Main Outcomes and Measures: Outcomes measured were maximum asthma symptom-days, exhaled FENO, and spirometry, analyzed using repeated measures negative binomial and linear mixed effects regression models, respectively. Models controlled for age, sex, race/ethnicity, BMI, household income, controller medication, allergen sensitization, season and co-pollutants. Allergen sensitization and season were tested as effect modifiers. Results: Participants with higher IQR increase in ⍺-PR and -PR had significant reduction in FEV₁/FVC z-score (−0.26; 95% CI: −0.49, −0.03; p = 0.029; and −0.23; 95% CI: −0.43, −0.02; p = 0.030 respectively). Conclusions and Relevance: α-PR and β-PR were associated with lower lung function. This identifies exposure to radon decay products as a novel environmental risk factor to consider for airway inflammation and impaired lung function. Findings could inform future mitigation studies directed at improving lung health in children Paper 2 RATIONALE Improvements in neonatal survival have increased the prevalence of bronchopulmonary dysplasia (BPD). Neonatal predictors of long-term respiratory outcomes in children with BPD only explain 8-40% of later lung function. New data show that radon exposure in children is linked to higher asthma prevalence and reduced lung function in children with asthma. We hypothesized that residential radon exposure during early childhood would be associated with increased asthma diagnoses and reduced lung function in school-aged children with BPD. METHODS This was a secondary analysis of the Air Quality, Environment, and Respiratory Outcomes in Bronchopulmonary Dysplasia (AEROBPD) study, a prospective cohort of children aged 6-12 years with a known diagnosis of BPD. Exposure was annualized average residential radon (Rn), generated by time-weighted geo-spatial estimates from all home addresses since birth. Participant addresses were coded to ZIP codes, and monthly estimates of ZIP-Code Tabulation Area (ZCTA) residential Rn were derived using a previously validated model. Primary outcomes included asthma prevalence (based on physician diagnosis) and lung function (Forced Expiratory Volume in the 1st second (FEV1 ) z-score measured with spirometry. Logistic and linear regression models were used to examine the relationship between radon exposure and outcomes. Interaction by BPD severity was tested. Significance was set at a two-sided p-value of 0.05. RESULTS A total of 147 children, with a mean (SD) age of 8.4 (2.4) years, 56% male, were included. The average lifetime radon level was 65.4 (17.3) Bq/m3 (mean [SD]), while the average level during the first year of life was 63.9 (18.2) Bq/m3. No significant associations were found between radon levels and any outcomes after adjusting for age, sex, gestational age, birth weight, BMI, race, ethnicity, family income, and BPD severity. BPD severity was significantly associated with lower lung function (FEV1 z-score) [β = -0.57; 95% CI: -1.01 to -0.14; p=0.011], but radon exposure's effect on lung function was not modified by BPD severity [interaction β= -0.007; 95% CI: -0.034 to 0.02; p=0.6]. CONCLUSION Early childhood exposure to radon may not independently increase the risk of asthma or reduce lung function in school-aged children with BPD. Larger studies and direct radon exposure measures are needed to confirm these findings.application/pdfenAsthmaBronchopulmonary dysplasiaLung functionparticle radioactivityRadon decay productschool-aged childrenPediatricsEnvironmental healthEpidemiologyThesis or Dissertation2026-05-040000-0002-2237-3663