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Table 2 Crude and adjusted odds ratios (OR) for low birth weight by pollution exposure

From: Maternal exposure to low-level air pollution and pregnancy outcomes: a population-based study

Exposure Crude odds ratio Adjusted* odds ratio Adjusted† odds ratio
  OR (95%CI) OR (95%CI) OR (95%CI)
Formaldehyde Categorical variable (tertiles)
1 (reference)    
2 1.27 (0.82–1.95) 1.86 (1.10–3.16) 2.15 (0.96–4.81)
3 1.39 (0.91–2.12) 1.84 (1.12–3.03) 2.09 (1.03–4.26)
Continuous variable (per 5 μg/m3 increase in concentration)
  1.07 (0.74–1.53) 1.10 (0.75–1.64) 1.36 (0.75–2.47)
Nitrogen dioxide Categorical variable (tertiles)
1 (reference)    
2 0.95 (0.61–1.47) 1.11 (0.70–1.77) 0.96 (0.47–1.96)
3 1.37 (0.91–2.07) 1.64 (1.04–2.58) 1.54 (0.80–2.96)
Continuous variable (per 10 μg/m3 increase in concentration)
  1.15 (0.97–1.36) 1.23 (1.02–1.48) 1.28 (0.97–1.68)
  1. * Adjusted for parity, maternal age (≤ 19, 20–29, 30–34, ≥ 35), marital status, education, season of birth, maternal and paternal smoking † As above plus gestational age