Environment/Climate Change
Sensitive childhood window of long-term exposure to air pollution on adult bronchitic symptoms Futu Chen* Futu Chen Zhongzheng Niu Sahra Mohazzab-Hosseinian Steve Howland Frederick Lurmann Nathan R. Pavlovic Rob McConnell Shohreh F. Farzan Theresa M. Bastain Rima Habre Carrie V. Breton Erika Garcia
Childhood exposure to air pollution appears to have long-term effects on adult bronchitic symptoms. However, the critical window of exposure is understudied. Using data from the Southern California Children’s Health Study (CHS), we assessed sensitive childhood ages for NO2 and O3 exposure associated with self-reported adult bronchitic symptoms.
We included 3 CHS cohorts (2 recruited at age ~9-10 years in 1992-93; 1 at age ~5-7 years in 2002-03) followed until high school graduation and included a follow up study in adulthood. Self-reported bronchitic symptoms in past 12 months was evaluated at adult assessment (mean age±SD=33±3 years) by questionnaire. Yearly average 24hr mean NO2 and 8hr max O3 exposure from in-utero to age 16 years was estimated using inverse-distance squared spatial interpolation and participants’ residential history. Log Poisson Distributed Lag Models adjusted for childhood and adult confounders were fitted to examine childhood exposure associations with adult bronchitic symptoms.
We included 823 (NO2) to 844 (O3) participants with complete yearly exposure data. 21% reported adult bronchitic symptoms in the past 12 months. Higher NO2 exposure during ages 1-4 years was associated with higher risk of adult bronchitic symptoms, with the largest associations observed at ages 2 (RR per 10ppb=1.09 [95% CI: 1.03, 1.16]) and 3 (RR=1.09 [1.02, 1.16]), with some suggestive evidence of increased risk at ages 11-13 years. Findings remained consistent after adjusting for O3. For O3, we observed increased risk at ages 13 (RR=1.14 [1.02,1.29]) and 14 (RR=1.12 [1.02,1.23]) in the two-pollutant model. Sensitivity analyses using imputed exposure and covariate data (n=1,319) produced similar results, but shifted toward the null.
We found evidence early life (1-4 years) might be a particularly sensitive window to NO2 exposure for bronchitic symptoms in adulthood. Puberty (11-14 years) might be a sensitive window for both NO2 and O3, but results were less consistent.
