title: Ambient air pollutant PM10 and risk of preterm birth in Lanzhou, China.
abstract: OBJECTIVE
  Exposure to ambient particulate matter during pregnancy has been suggested as a risk factor for preterm birth. However results from limited epidemiologic studies have been inconclusive. Very few studies have been conducted in areas with high air pollution levels.
  
  
  OBJECTIVE
  We investigated the hypothesis that high level exposure to particulate matter with aerodynamic diameter no larger than 10μm (PM10) during pregnancy increases the risk of preterm birth.
  
  
  METHODS
  A birth cohort study was carried out between 2010 and 2012 in Lanzhou, China, including 8969 singleton live births with available information on daily PM10 levels from four monitoring stations, individual exposures during pregnancy were calculated using inverse-distance weighting based on both home and work addresses. Unconditional logistic regression modeling was used to examine the associations between PM10 exposure and risk of preterm birth and its clinical subtypes.
  
  
  RESULTS
  Increased risk of very preterm birth was associated with exposure to PM10 during the last two months of pregnancy (OR, 1.07; 95%CI, 1.02-1.13 per 10μg/m(3) increase for last four weeks before delivery; 1.09; 1.02-1.15 for last six weeks before delivery; 1.10; 1.03-1.17 for last eight weeks before delivery). Compared to the U.S. National Ambient Air Quality Standard (150μg/m(3)), higher exposure level (≥150μg/m(3)) of PM10 during entire pregnancy was associated with an increased risk of preterm birth (1.48; 1.22-1.81) and the association was higher for medically indicated preterm birth (1.80, 1.24-2.62) during entire pregnancy and for very preterm during last 6weeks before delivery (2.03, 1.11-3.72).
  
  
  CONCLUSIONS
  Our study supports the hypothesis that exposure to high levels of ambient PM10 increases the risk of preterm birth. Our study also suggests that the risk may vary by clinical subtypes of preterm birth and exposure time windows. Our findings are relevant for health policy makers from China and other regions with high levels of air pollution to facilitate the efforts of reducing air pollution level in order to protect public health.
authors.affiliation: Yale University, School of Public Health, New Haven, CT, USA.
authors.forename: Nan
authors.initials: N
authors.lastname: Zhao
authors.affiliation: Gansu Provincial Maternity and Child Care Hospital, Lanzhou, Gansu, China.
authors.forename: Jie
authors.initials: J
authors.lastname: Qiu
authors.affiliation: Gansu Provincial Design and Research Institute of Environmental Science, Lanzhou, Gansu, China.
authors.forename: Yaqun
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Gansu Provincial Maternity and Child Care Hospital, Lanzhou, Gansu, China.
authors.forename: Xiaochun
authors.initials: X
authors.lastname: He
authors.affiliation: Gansu Provincial Maternity and Child Care Hospital, Lanzhou, Gansu, China.
authors.forename: Min
authors.initials: M
authors.lastname: Zhou
authors.affiliation: Gansu Provincial Environmental Monitoring Central Station, Lanzhou, Gansu, China.
authors.forename: Min
authors.initials: M
authors.lastname: Li
authors.affiliation: Gansu Provincial Maternity and Child Care Hospital, Lanzhou, Gansu, China.
authors.forename: Xiaoying
authors.initials: X
authors.lastname: Xu
authors.affiliation: Gansu Provincial Maternity and Child Care Hospital, Lanzhou, Gansu, China.
authors.forename: Hongmei
authors.initials: H
authors.lastname: Cui
authors.affiliation: Gansu Provincial Maternity and Child Care Hospital, Lanzhou, Gansu, China.
authors.forename: Ling
authors.initials: L
authors.lastname: Lv
authors.affiliation: Gansu Provincial Maternity and Child Care Hospital, Lanzhou, Gansu, China.
authors.forename: Xiaojuan
authors.initials: X
authors.lastname: Lin
authors.affiliation: Gansu Provincial Maternity and Child Care Hospital, Lanzhou, Gansu, China.
authors.forename: Chong
authors.initials: C
authors.lastname: Zhang
authors.affiliation: Gansu Provincial Maternity and Child Care Hospital, Lanzhou, Gansu, China.
authors.forename: Honghong
authors.initials: H
authors.lastname: Zhang
authors.affiliation: Gansu Provincial Maternity and Child Care Hospital, Lanzhou, Gansu, China.
authors.forename: Ruifeng
authors.initials: R
authors.lastname: Xu
authors.affiliation: Gansu Provincial Maternity and Child Care Hospital, Lanzhou, Gansu, China.
authors.forename: Daling
authors.initials: D
authors.lastname: Zhu
authors.affiliation: Gansu Provincial Maternity and Child Care Hospital, Lanzhou, Gansu, China.
authors.forename: Ru
authors.initials: R
authors.lastname: Lin
authors.affiliation: Gansu Provincial Maternity and Child Care Hospital, Lanzhou, Gansu, China.
authors.forename: Tingting
authors.initials: T
authors.lastname: Yao
authors.affiliation: Gansu Provincial Maternity and Child Care Hospital, Lanzhou, Gansu, China.
authors.forename: Jie
authors.initials: J
authors.lastname: Su
authors.affiliation: Gansu Provincial Maternity and Child Care Hospital, Lanzhou, Gansu, China.
authors.forename: Yun
authors.initials: Y
authors.lastname: Dang
authors.affiliation: Gansu Provincial Maternity and Child Care Hospital, Lanzhou, Gansu, China.
authors.forename: Xudong
authors.initials: X
authors.lastname: Han
authors.affiliation: Gansu Provincial Maternity and Child Care Hospital, Lanzhou, Gansu, China.
authors.forename: Hanru
authors.initials: H
authors.lastname: Zhang
authors.affiliation: Gansu Provincial Maternity and Child Care Hospital, Lanzhou, Gansu, China.
authors.forename: Haiya
authors.initials: H
authors.lastname: Bai
authors.affiliation: Gansu Provincial Maternity and Child Care Hospital, Lanzhou, Gansu, China.
authors.forename: Ya
authors.initials: Y
authors.lastname: Chen
authors.affiliation: Gansu Provincial Maternity and Child Care Hospital, Lanzhou, Gansu, China.
authors.forename: Zhongfeng
authors.initials: Z
authors.lastname: Tang
authors.affiliation: Gansu Provincial Maternity and Child Care Hospital, Lanzhou, Gansu, China.
authors.forename: Wendi
authors.initials: W
authors.lastname: Wang
authors.affiliation: Gansu Provincial Maternity and Child Care Hospital, Lanzhou, Gansu, China.
authors.forename: Yueyuan
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Gansu Provincial Maternity and Child Care Hospital, Lanzhou, Gansu, China.
authors.forename: Xiaohui
authors.initials: X
authors.lastname: Liu
authors.affiliation: Gansu Provincial Maternity and Child Care Hospital, Lanzhou, Gansu, China.
authors.forename: Bin
authors.initials: B
authors.lastname: Ma
authors.affiliation: Gansu Provincial Maternity and Child Care Hospital, Lanzhou, Gansu, China.
authors.forename: Sufen
authors.initials: S
authors.lastname: Liu
authors.affiliation: Gansu Provincial Maternity and Child Care Hospital, Lanzhou, Gansu, China.
authors.forename: Weitao
authors.initials: W
authors.lastname: Qiu
authors.affiliation: Yale University, School of Public Health, New Haven, CT, USA.
authors.forename: Huang
authors.initials: H
authors.lastname: Huang
authors.affiliation: Yale University, School of Public Health, New Haven, CT, USA.
authors.forename: Jiaxin
authors.initials: J
authors.lastname: Liang
authors.affiliation: Henan Province Cancer Hospital, Office for Cancer Control and Prevention, Affiliated Cancer Hospital of Zhengzhou University, Zhengzhou, Henan, China.
authors.forename: Qiong
authors.initials: Q
authors.lastname: Chen
authors.affiliation: Sichuan University School of Public Health, Chengdu, Sichuan, China.
authors.forename: Min
authors.initials: M
authors.lastname: Jiang
authors.affiliation: Yale University, School of Public Health, New Haven, CT, USA.
authors.forename: Shuangge
authors.initials: S
authors.lastname: Ma
authors.affiliation: Yale University, School of Forestry and Environmental Studies, New Haven, CT, USA.
authors.forename: Lan
authors.initials: L
authors.lastname: Jin
authors.affiliation: Yale University, School of Public Health, New Haven, CT, USA.
authors.forename: Theodore
authors.initials: T
authors.lastname: Holford
authors.affiliation: Yale University, School of Public Health, New Haven, CT, USA.
authors.forename: Brian
authors.initials: B
authors.lastname: Leaderer
authors.affiliation: Yale University, School of Forestry and Environmental Studies, New Haven, CT, USA.
authors.forename: Michelle L
authors.initials: ML
authors.lastname: Bell
authors.affiliation: Gansu Provincial Maternity and Child Care Hospital, Lanzhou, Gansu, China. Electronic address: 2305470816@qq.com.
authors.forename: Qing
authors.initials: Q
authors.lastname: Liu
authors.affiliation: Yale University, School of Public Health, New Haven, CT, USA. Electronic address: yawei.zhang@yale.edu.
authors.forename: Yawei
authors.initials: Y
authors.lastname: Zhang
mesh_terms: D002681:China / Q000453:epidemiology; D015331:Cohort Studies; D004781:Environmental Exposure / Q000009:adverse effects* / Q000032:analysis; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D016015:Logistic Models; D008297:Male; D010316:Particle Size; D052638:Particulate Matter / Q000032:analysis / Q000633:toxicity*; D011247:Pregnancy; D047928:Premature Birth / Q000139:chemically induced* / Q000453:epidemiology*; D011634:Public Health / Q000706:statistics & numerical data*; D012307:Risk Factors; D013997:Time Factors
chemical_list: D052638:Particulate Matter
keywords: Air pollution; Birth cohort; China; Epidemiology; PM(10); Preterm birth