title: Particulate matter exposure during pregnancy is associated with birth weight, but not gestational age, 1962-1992: a cohort study.
abstract: BACKGROUND
  Exposure to air pollutants is suggested to adversely affect fetal growth, but the evidence remains inconsistent in relation to specific outcomes and exposure windows.
  
  
  METHODS
  Using birth records from the two major maternity hospitals in Newcastle upon Tyne in northern England between 1961 and 1992, we constructed a database of all births to mothers resident within the city. Weekly black smoke exposure levels from routine data recorded at 20 air pollution monitoring stations were obtained and individual exposures were estimated via a two-stage modeling strategy, incorporating temporally and spatially varying covariates. Regression analyses, including 88,679 births, assessed potential associations between exposure to black smoke and birth weight, gestational age and birth weight standardized for gestational age and sex.
  
  
  RESULTS
  Significant associations were seen between black smoke and both standardized and unstandardized birth weight, but not for gestational age when adjusted for potential confounders. Not all associations were linear. For an increase in whole pregnancy black smoke exposure, from the 1(st) (7.4 μg/m(3)) to the 25(th) (17.2 μg/m(3)), 50(th) (33.8 μg/m(3)), 75(th) (108.3 μg/m(3)), and 90(th) (180.8 μg/m(3)) percentiles, the adjusted estimated decreases in birth weight were 33 g (SE 1.05), 62 g (1.63), 98 g (2.26) and 109 g (2.44) respectively. A significant interaction was observed between socio-economic deprivation and black smoke on both standardized and unstandardized birth weight with increasing effects of black smoke in reducing birth weight seen with increasing socio-economic disadvantage.
  
  
  CONCLUSIONS
  The findings of this study progress the hypothesis that the association between black smoke and birth weight may be mediated through intrauterine growth restriction. The associations between black smoke and birth weight were of the same order of magnitude as those reported for passive smoking. These findings add to the growing evidence of the harmful effects of air pollution on birth outcomes.
authors.affiliation: Institute of Health and Society, Newcastle University, Newcastle upon Tyne, England, UK. mark.pearce@ncl.ac.uk
authors.forename: Mark S
authors.initials: MS
authors.lastname: Pearce
authors.forename: Svetlana V
authors.initials: SV
authors.lastname: Glinianaia
authors.forename: Rakesh
authors.initials: R
authors.lastname: Ghosh
authors.forename: Judith
authors.initials: J
authors.lastname: Rankin
authors.forename: Steven
authors.initials: S
authors.lastname: Rushton
authors.forename: Martin
authors.initials: M
authors.lastname: Charlton
authors.forename: Louise
authors.initials: L
authors.lastname: Parker
authors.forename: Tanja
authors.initials: T
authors.lastname: Pless-Mulloli
mesh_terms: D000293:Adolescent; D000328:Adult; D000393:Air Pollutants / Q000032:analysis* / Q000633:toxicity; D001724:Birth Weight; D002947:Cities / Q000453:epidemiology; D015331:Cohort Studies; D004739:England / Q000453:epidemiology; D004781:Environmental Exposure; D005260:Female; D005865:Gestational Age; D006801:Humans; D007231:Infant, Newborn; D008297:Male; D018811:Maternal Exposure; D008875:Middle Aged; D052638:Particulate Matter / Q000032:analysis / Q000633:toxicity*; D011247:Pregnancy; D011256:Pregnancy Outcome / Q000453:epidemiology*; D012044:Regression Analysis; D012737:Sex Factors; D012906:Smoke / Q000032:analysis; D055815:Young Adult
chemical_list: D000393:Air Pollutants; D052638:Particulate Matter; D012906:Smoke