Xin Liu1, Yufeng Ye2, Yi Chen2, Xiaona Li3, Baixiang Feng1, Ganxiang Cao1, Jianpeng Xiao1, Weilin Zeng1, Xing Li1, Jiufeng Sun1, Dan Ning1, Yi Yang4, Zhenjiang Yao4, Yuming Guo5, Qiong Wang6, Yonghui Zhang7, Wenjun Ma8, Qingfeng Du9, Bo Zhang10, Tao Liu11. 1. Guangdong Provincial Institute of Public Health, Guangdong Provincial Center for Disease Control and Prevention, Guangzhou 511430, China. 2. Guangzhou Panyu Central Hospital, Guangzhou 511400, China. 3. Department of Environmental and Occupational Health, School of Public Health, Sun Yat-sen University, Guangzhou 510080, China. 4. School of Public Health, Guangdong Pharmaceutical University, Guangzhou 510080, China. 5. Department of Epidemiology and Preventive Medicine, School of Public Health and Preventive Medicine, Monash University, Melbourne, Australia. 6. School of Public Health, Sun Yat-sen University, Guangzhou 510080, China. 7. Guangdong Provincial Center for Disease Control and Prevention, Guangzhou 511430, China. 8. Guangdong Provincial Institute of Public Health, Guangdong Provincial Center for Disease Control and Prevention, Guangzhou 511430, China; General Practice Center, Nanhai Hospital, Southern Medical University, Foshan 528200, China. 9. General Practice Center, Nanhai Hospital, Southern Medical University, Foshan 528200, China. 10. Food Safety and Health Research Center, School of Public Health, Southern Medical University, Guangzhou 510515, China; Department of Environmental and Occupational Health, School of Public Health, Sun Yat-sen University, Guangzhou 510080, China. Electronic address: cnzhangbo@126.com. 11. Guangdong Provincial Institute of Public Health, Guangdong Provincial Center for Disease Control and Prevention, Guangzhou 511430, China; General Practice Center, Nanhai Hospital, Southern Medical University, Foshan 528200, China. Electronic address: gztt_2002@163.com.
Abstract
BACKGROUND: Epidemiological studies have found that increased risk of preterm birth (PTB) is associated with higher prenatal exposure to PM10 and PM2.5, but few studies have been conducted to assess the impacts of extremely fine particulate matter (PM1) which may have more toxic effects than other types of ambient particulate air pollution (PM). Several studies have separately investigated the associations between DNA methylation and PTB risk and PM. Maternal LINE-1 methylation level negatively correlated with prenatal exposure to PM and risk of PTB. A comprehensive picture is lacking regarding the associations between prenatal exposure to PM, LINE-1 methylation, and risk of PTB. OBJECTIVES: This study aimed to estimate the effects of exposure to ambient PM (PM10, PM2.5, and PM1) of different sizes during pregnancy on risk of PTB, identify susceptible exposure windows, and illustrate the roles of LINE-1 methylation in the associations between PM and PTB risk. METHODS: The Birth Cohort Study on Prenatal Environments and Offspring Health (PEOH) has been ongoing since 2016 in Guangzhou, China. A total of 4928 pregnant women were recruited during early pregnancy, and 4278 (86.8%) were successfully followed-up. Each individual weekly exposure to PM10 and PM2.5 from 3 months before pregnancy to childbirth was assessed using a spatiotemporal land use regression model, and the weekly PM1 exposure was estimated by employing a generalized additive model. Maternal and cord blood LINE-1 methylation levels (%5mC) were tested using bisulfite-PCR pyrosequencing. A distributed lag nonlinear model incorporated with a Cox proportional hazard model was applied to assess the effect of weekly-specific maternal PM exposure on PTB risk, and a multiple-linear regression model was employed to investigate the associations between PM exposure and LINE-1 methylation levels of maternal and cord bloods. We also assessed the associations between LINE-1 methylation levels and PTB risk by using a logistic regression model. RESULTS: The risk of PTB was positively associated with PM2.5 and PM1 concentrations during the 12th to 20th gestational weeks, and the strongest association was in the fourth quartile (Q4) versus the first quartile (Q1) and observed during the 16th gestational week (PM2.5: harzard ratio [HR] = 1.18, 95%CI: 1.04-1.35, IQR = 11.94 μg/m3. PM1: HR = 1.20, 95%CI: 1.03-1.39, IQR = 11.36 μg/m3). We observed significantly negative associations of PM10(β = -0.51%5mC per 10 μg/m3, P = 0.014), PM2.5 (β = -0.66%5mC per 10 μg/m3, P = 0.032) and PM1 (β = -0.67%5mC per 10 μg/m3, P = 0.032) concentrations with cord blood LINE-1 methylation levels, and a negative association between PM1 concentration and maternal LINE-1 methylation level (β = -0.86%5mC per 10 μg/m3, P = 0.034). CONCLUSION: Higher prenatal exposure to PM1 and PM2.5 during the 12th to 20th gestational weeks was associated with increased risk of PTB. Maternal and fetal LINE-1 methylation alternation might be an underlying mechanism of PM that increasing the risk of PTB.
BACKGROUND: Epidemiological studies have found that increased risk of preterm birth (PTB) is associated with higher prenatal exposure to PM10 and PM2.5, but few studies have been conducted to assess the impacts of extremely fine particulate matter (PM1) which may have more toxic effects than other types of ambient particulate air pollution (PM). Several studies have separately investigated the associations between DNA methylation and PTB risk and PM. Maternal LINE-1 methylation level negatively correlated with prenatal exposure to PM and risk of PTB. A comprehensive picture is lacking regarding the associations between prenatal exposure to PM, LINE-1 methylation, and risk of PTB. OBJECTIVES: This study aimed to estimate the effects of exposure to ambient PM (PM10, PM2.5, and PM1) of different sizes during pregnancy on risk of PTB, identify susceptible exposure windows, and illustrate the roles of LINE-1 methylation in the associations between PM and PTB risk. METHODS: The Birth Cohort Study on Prenatal Environments and Offspring Health (PEOH) has been ongoing since 2016 in Guangzhou, China. A total of 4928 pregnant women were recruited during early pregnancy, and 4278 (86.8%) were successfully followed-up. Each individual weekly exposure to PM10 and PM2.5 from 3 months before pregnancy to childbirth was assessed using a spatiotemporal land use regression model, and the weekly PM1 exposure was estimated by employing a generalized additive model. Maternal and cord blood LINE-1 methylation levels (%5mC) were tested using bisulfite-PCR pyrosequencing. A distributed lag nonlinear model incorporated with a Cox proportional hazard model was applied to assess the effect of weekly-specific maternal PM exposure on PTB risk, and a multiple-linear regression model was employed to investigate the associations between PM exposure and LINE-1 methylation levels of maternal and cord bloods. We also assessed the associations between LINE-1 methylation levels and PTB risk by using a logistic regression model. RESULTS: The risk of PTB was positively associated with PM2.5 and PM1 concentrations during the 12th to 20th gestational weeks, and the strongest association was in the fourth quartile (Q4) versus the first quartile (Q1) and observed during the 16th gestational week (PM2.5: harzard ratio [HR] = 1.18, 95%CI: 1.04-1.35, IQR = 11.94 μg/m3. PM1: HR = 1.20, 95%CI: 1.03-1.39, IQR = 11.36 μg/m3). We observed significantly negative associations of PM10(β = -0.51%5mC per 10 μg/m3, P = 0.014), PM2.5 (β = -0.66%5mC per 10 μg/m3, P = 0.032) and PM1 (β = -0.67%5mC per 10 μg/m3, P = 0.032) concentrations with cord blood LINE-1 methylation levels, and a negative association between PM1 concentration and maternal LINE-1 methylation level (β = -0.86%5mC per 10 μg/m3, P = 0.034). CONCLUSION: Higher prenatal exposure to PM1 and PM2.5 during the 12th to 20th gestational weeks was associated with increased risk of PTB. Maternal and fetal LINE-1 methylation alternation might be an underlying mechanism of PM that increasing the risk of PTB.
Authors: Xin-Chen Liu; Esben Strodl; Li-Hua Huang; Qing Lu; Yang Liang; Wei-Qing Chen Journal: Int J Environ Res Public Health Date: 2022-09-18 Impact factor: 4.614
Authors: Andreas M Neophytou; Marianthi-Anna Kioumourtzoglou; Dana E Goin; Kristin C Darwin; Joan A Casey Journal: Int J Epidemiol Date: 2021-03-03 Impact factor: 7.196