Portable HEPA Filter Air Cleaner Use During Pregnancy and Children’s Behavior Problem Scores: The UGAAR Randomized Controlled Trial

Abstract

BACKGROUND AND AIM: Developmental exposure to fine particulate matter (PM2.5) may impair children’s behaviors; the timing of exposure may also play an important role. METHODS: In this single-blind parallel-group randomized controlled trial, we randomly allocated 540 non-smoking pregnant women in Ulaanbaatar, Mongolia to receive 1-2 portable HEPA filter air cleaners from enrollment until the end of pregnancy or no air cleaners. We administered the Behavior Assessment System for Children, 3rd Edition (BASC-3) to caregivers when children were a mean age of 23 months, and again at 48 months. The primary outcomes were the four BASC-3 composite scales. We imputed missing outcome data using multiple imputation with chained equations and our primary analysis was by intention to treat (ITT). In a secondary analysis, we evaluated associations between BASC-3 composite indices and trimester-specific indoor PM2.5 concentrations. RESULTS:We enrolled participants at a median of 11-weeks gestation. After excluding pregnancy losses and neonatal deaths, analysis included 478 children (233 control and 245 intervention). No differences in mean BASC-3 scores were found between groups. In a secondary analysis, indoor PM2.5 during first trimester of pregnancy was associated with worse behavior scores at age 4. An interquartile range (20.1 µg/m3) increase in PM2.5 was associated with higher behavioral problem scores for externalizing (2.4, 95% CI: 0.7, 4.1), internalizing (2.4, 95% CI: 0.7, 4.0), and behavioral symptoms index (2.3, 95% CI: 0.7, 3.9). No significant associations for PM2.5 concentrations observed during the second trimester or any of the BASC indices at age 2. CONCLUSIONS:We found no benefit of reducing indoor air pollutants during early brain development on children’s behaviors. Childhood behavior may be sensitive to indoor PM2.5 concentrations during first trimester and interventions in early pregnancy may be necessary to protect children. However, these exploratory findings should be interpreted cautiously and require replication. KEYWORDS: Particulate matter, Neurodevelopmental outcome, Children's environmental health