Long-term exposure to PM2.5 and Children's lung function: a dose-based association analysis.

BACKGROUND

The current literature is still not consist regarding the effect of long-term exposure to PM2.5 and children's lung function, partly due to inadequate or inaccurate exposure assessment. In this study, we aim to investigate the associations between long-term exposure to PM2.5, estimated as average daily dose (ADD), and lung function in school-age children.

METHODS

We recruited 684 participants of 7-12 years old from the city of Lanzhou located in northwestern China. Participants underwent spirometric tests for lung function and responded to a questionnaire survey. Detailed information about individual air exposure and personal information were collected, including length of school hours, home address, age, gender, etc. Combining the spatial distribution of PM2.5 concentrations in the past 5 years and individual time-activity data, we estimated annual ADD for 5 years preceding the lung function tests and 5-year average ADD, respectively. We used multiple linear regression models to examine the associations between ADD values and lung function, controlling for a range of individual-level covariates.

RESULTS

The 5-year average ADD among all the participants was 50.5 µg/kg-d, with higher values estimated for children living in the urban area than the suburban area, for boys than girls, and for children whose parents received a lower education attainment. We found that a 1 μg/kg-d increment in ADD of PM2.5 was associated with a 10.49 mL (95% CI: -20.47, -0.50) decrease in forced vital capacity (FVC) and a 7.68 mL (95% CI: -15.80, -0.44) decrease in forced exploratory volume in 1 second (FEV

CONCLUSIONS

Long-term PM2.5 exposure, when estimated as exposure dose averaged over a year or longer, was associated with statistically significant reductions in FVC and FEV1 in children of elementary-school age. Future studies may consider the use of individual-level dose estimates (as opposed to exposure concentrations) to improve the dose-response assessment.

Informations de copyright

2020 Journal of Thoracic Disease. All rights reserved.

Déclaration de conflit d'intérêts

Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at http://dx.doi.org/10.21037/jtd-19-crh-aq-007). The series “Children’s Respiratory Health and Air Quality” was commissioned by the editorial office without any funding or sponsorship. JJZ, HK and HK served as the unpaid Guest Editors of the series. JJZ also and serves as an unpaid editorial board member of Journal of Thoracic Disease. The other authors have no other conflicts of interest to declare.