Prenatal and early life exposure to air pollution and lung function development aged 8-24 years: The ALSPAC study

Background:
Associations have been found between early-life air pollution exposures and lung function during childhood, but evidence is limited on lung function growth.

Objectives:
Evaluate whether elevated air pollution during pregnancy and early life is associated with reduced lung function growth aged 8–24 years.

Methods:
We investigated ∼5200 children from the ALSPAC UK birth cohort with longitudinal lung function data at ages 8, 15 and 24 years. Mixed-effects linear models with individual level random intercepts were used to evaluate the associations between prenatal and early life exposure to source-specific PM10 (total/road/other) and NO2 and annual growth in forced expiratory volume (FEV1), forced vital capacity (FVC), forced expiratory flow (FEF25-75) and FEV1/FVC lung function z-scores, adjusting for preterm birth, SES, smoke exposure/current smoking, damp, season, allergy, breastfeeding and BMI.

Results:
We found small reductions in all measures of annual lung function growth z-scores across ages 8-24 years, in relation to prenatal and early-life air pollution exposure, with -0.0122 (-0.016, -0.008) FEV1(z) per 1 unit increase in PM10_road exposure. The magnitude of effect was larger for lung function growth from age 8 up to age 15 years, -0.0396 (-0.046, -0.033) FEV1(z), than to age 24 years.

Conclusion:
Exposure to higher levels of source-specific PM10, and NO2 air pollution, during pregnancy and early childhood may impact lung function development, with greatest effects in adolescence, the time of fastest growth. Results are consistent with earlier findings within other cohorts with follow-ups into adolescence, but extends findings to age 24 years and mid-expiratory flows.