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Table 5 Odds ratios (ORs) of adverse birth outcomes associated with proximity to major roads (≤200 m) stratified by individual/area-level SEP and parental characteristics

From: Residential proximity to major roads and adverse birth outcomes: a hospital-based study

  PTB* Term LBW*
  OR (95% CI) AP (95% CI) OR (95% CI) AP (95% CI)
Individual SEP or personal characteristics     
Household occupation†     
  Professional workers 1.6 (0.8, 3.2) - 1.4 (0.6, 3.3) -
  Employees 1.5 (1.2, 1.9) 0 (−0.6, 0.6) 1.1 (0.9, 1.5) −0.2 (−1.2, 0.7)
  Self-employed/Part-time workers/Unemployed 1.6 (0.7, 3.5) 0.2 (−0.6, 1.0) 3.1 (1.2, 8.2) 0.4 (−0.3, 1.1)
Maternal smoking†     
  Never smoked 1.6 (1.3, 2.0) - 1.2 (0.9, 1.5) -
  Ex- or current-smoker 0.8 (0.3, 1.8) −0.5 (−1.6, 0.7) 2.4 (1.0, 6.2) 0.5 (0, 1.0)
Maternal alcohol drinking†     
  Non-drinker 1.6 (1.3, 1.9) - 1.2 (1.0, 1.6) -
  Drinker 1.2 (0.4, 3.3) −0.2 (−1.3, 1.0) 0.7 (0.1, 3.3) −0.8 (−3.6, 1.9)
Paternal smoking†     
  Never smoked 1.7 (1.3, 2.2) - 1.2 (0.8, 1.7) -
  Ex or current-smoker 1.4 (1.1, 1.9) −0.1 (−0.6, 0.3) 1.2 (0.9, 1.8) −0.1 (−0.9, 0.8)
Maternal obesity†     
  Not obese 1.6 (1.3, 2.0) - 1.2 (0.9, 1.6) -
  Obese 1.3 (0.7, 2.5) −0.1 (−0.8, 0.6) 1.6 (0.7, 3.6) 0.2 (−0.5, 0.9)
Maternal diabetes†     
  No diabetes 1.5 (1.2, 1.8) - 1.2 (0.9, 1.6) -
  Diabetes 4.4 (1.9, 10.0) 0.6 (0.4, 0.9) 1.4 (0.3, 7.0) 0 (−1.5, 1.5)
Maternal hypertension†     
  No hypertension 1.5 (1.2, 1.8) - 1.3 (1.0, 1.6) -
  Hypertension 2.6 (1.2, 5.4) 0.4 (0, 0.9) 0.5 (0.1, 2.5) −1.1 (−4.2, 2.0)
Area-level SEP at census regions     
Proportion of professional workers§     
  Q1 (affluent) 1.9 (1.2, 3.0) - 1.4 (0.8, 2.6) -
  Q2 (middle) 1.6 (1.2, 2.2) −0.2 (−0.8, 0.4) 1.3 (0.9, 1.9) 0 (−0.6, 0.6)
  Q3 (poor) 1.4 (1.1, 1.9) −0.2 (−0.7, 0.4) 1.1 (0.7, 1.6) −0.2 (−1.0, 0.6)
Proportion of production or transportation workers§     
  Q1 (affluent) 2.5 (1.4, 4.4) - 2.5 (1.1, 5.5) -
  Q2 (middle) 1.2 (0.9, 1.7) −0.9 (−2.1, 0.2) 1.2 (0.8, 1.8) −0.9 (−2.5, 0.7)
  Q3 (poor) 1.6 (1.2, 2.2) −0.3 (−0.9, 0.4) 1.0 (0.7, 1.6) −1.1 (−2.9, 0.7)
  1. ORs were estimated against subjects living in the area more than 200 m from major roads. Proportions attributable to the interaction (AP) between the respective factors and proximity to major roads are also shown.
  2. *Subjects were all newborns (n = 16,615) in the analyses for PTB and subjects were newborns at term birth (n = 14,836) in the analyses for term LBW.
  3. †Adjusted for maternal age, newborn’s sex, maternal smoking, maternal alcohol consumption, maternal body mass index, paternal smoking, household occupation, and the proportion of professional workers in the corresponding census. Each confounder was excluded when subjects were stratified by the corresponding variable. Gestational age was also adjusted in the analysis for term LBW.
  4. §Adjusted for maternal age, newborn’s sex, maternal smoking, maternal alcohol consumption, maternal body mass index, paternal smoking, and household occupation. Gestational age was also adjusted in the analysis for term LBW.
  5. AP; Proportion attributable to the interaction, CI; confidence interval, LBW; low birth weight, OR; odds ratio, PTB; preterm birth, SEP; socio-economic position.