Association between prenatal exposure to PM2.5 and the increased risk of specified infant mortality in South Korea
- DOI
- Language of the publication
- English
- Date
- 2020-08-06
- Type
- Article
- Author(s)
- Jung, Eun Mi
- Kim, Kyoung-Nam
- Park, Hyesook
- Shin, Hwashin H.
- Kim, Hae Soon
- Cho, Su Jin
- Kim, Soon Tae
- Ha, Eun Hee
- Publisher
- Elsevier
Abstract
Background Findings from previous studies on the association between exposure to fine particulate matter (PM2.5) and the risk of infant mortality were inconsistent. Thus, two main objectives of our study were to examine the association between exposure to PM2.5 and specified infant mortality and to identify critical trimesters. Methods We retrospectively created a birth cohort of singleton full-term infants born in South Korea between 2010 and 2015 using national birth and infant mortality data. The specified causes of infant mortality were circulatory and respiratory diseases, perinatal conditions, congenital anomalies, and sudden infant death syndrome. We performed 1:10 propensity score matching for various exposure windows: each trimester, prenatal, and postnatal (up to age 1). Conditional logistic regression was applied to estimate odds ratios (ORs) and 95% confidence intervals (CIs), while accounting for gestational age, birth weight, maternal education level, season of birth, and regions (metropolitan areas/provinces). We also conducted sex-stratified analyses and used different matching ratios for sensitivity analyses. Results A total of 2,501,836 births and 761 deaths (0.03%) were identified in the birth cohort. We found an increased risk of infant mortality per 10 µg/m3 increase in PM2.5 exposure during the prenatal period (OR: 1.29, 95% CI: 1.07–1.55). Exposure in the 1st and 2nd trimesters was linked to an elevated risk (OR: 1.19, 95% CI: 1.02–1.37; OR: 1.21, 95% CI: 1.04–1.40). However, no association was shown in the third trimester. PM2.5 exposure in the 1st and 2nd trimesters was associated with elevated male infant mortality, but did not reach statistical significance in female infants. The use of different matching ratios did not significantly affect the results. Conclusion The study findings suggest that exposure to PM2.5 could affect infant mortality differently by the timing of exposure and sex, which suggests a relation to fetal development. However, further investigations are warranted.
Plain language summary
Health Canada is responsible for assessing the health risks of air pollution, and identifying specific vulnerable populations as part of the Addressing Air Pollution Horizontal Initiative. Previous studies have suggested that maternal exposure to air pollution during pregnancy led to adverse health effect on children. Numerous studies conducted worldwide have examined the association between air pollution and infant mortality but these were inconsistent and inconclusive. This study examined infant mortality (≤ 1 year) in relation with exposure to ambient PM2.5 based on a birth cohort for singleton full-term infants born in South Korea between 2010-2015. A total of 2,501,836 births and 761 deaths (0.03%) were identified from the birth cohort. A matched case-control (ratio 1:10) analysis was done for five exposure windows (each trimester, prenatal, and postnatal periods). The study findings suggest that adverse health effect of PM2.5 on infant mortality starts early pregnancy and continue to middle pregnancy, and is higher for male infants. This seems to be related to fetal development but the sex-related difference needs further investigations. This study was conducted in collaboration with scientists from Ewha Womans University, Seoul, Republic of Korea (department of Occupational and Environmental Medicine).
Subject
- Health,
- Health and safety