Identifying Critical Windows and Joint Effects of Prenatal Air Pollution and Temperature Exposure and Lung Function in Schoolchildren: Findings From a Prospective Birth Cohort Study.

BACKGROUND

Air pollution and extreme temperature exposure during pregnancy is associated with lung function in schoolchildren.

RESEARCH QUESTION: What are the critical time windows during pregnancy when exposure to air pollution (fine particulate matter [PM2.5] and nitrogen dioxide [NO2]) and temperature affects lung function in schoolchildren, and do these exposures interact?

STUDY DESIGN AND

METHODS

Within the Programming Research in Obesity, Growth, Environment, and Social Stressors study, daily residential levels of pollutant/temperature exposures during pregnancy were generated from satellite-based models. Lung function was evaluated at ages 8 to 14 years and was modeled as z scores adjusted for age, height, and sex. We used distributed lag nonlinear models to evaluate overall and sex-specific associations of exposures with lung function outcomes. Interactive effects were evaluated through the relative excess risk due to interaction and the attributable proportion.

RESULTS

A total of 429 mother-child dyads were included. Prenatal higher PM2.5 exposure was associated with reduced lung function parameters, including FEV1z score (weeks 1-21, cumulative change: -0.23 [95% CI, -0.39 to -0.07]), FVC z score (weeks 13-19, cumulative change: -0.04 [95% CI, -0.08 to -0.00]), forced expiratory flow at 25% to 75% of vital capacity (FEF25-75%) z score (weeks 1-20, cumulative change: -0.20 [95% CI, -0.36 to -0.04]), and FEV1/FVC ratio (weeks 6-16, cumulative change: -0.57 [95% CI, -0.11 to -0.04]). Similarly, increased NO2 exposure was associated with reduced FEV1z score (weeks 1-16, cumulative change: -0.16 [95% CI, -0.31 to -0.02]), FEF25-75%z score (weeks 13-16, -0.02 [95% CI, -0.04 to -0.00]), and FEV1/FVC ratio (weeks 6-15, -0.48 [95% CI, -0.96 to -0.01]). In contrast, both warmer (weeks 1-8) and colder temperatures (weeks 9-18) showed positive associations with FVC z score. Stronger associations were found in female participants. No interactive effects of air pollution and temperature were found.

INTERPRETATION: Our findings emphasize detrimental effects of early-life air pollution exposure on long-term respiratory health and suggest potential sex-specific vulnerabilities, informing targeted interventions to protect child health.