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Table 3 Associations between birth weight and an inter-quartile range in air pollution metrics, for pregnancy-long exposures (a)

From: Investigating the association between birth weight and complementary air pollution metrics: a cohort study

    Low birth weight Mean birth weight in grams
Air pollution metrics Inter-quartile range (IQR) in air pollution metrics Number of subjects Odds ratio per IQR increase in air pollution metrics 95% confidence interval p value Change for per IQR increase in air pollution metrics 95% confidence interval p value
Monitoring station measurements, nearest station approach without distance restrictions (b)
NO 2 11.87 68,303 0.85 0.76 0.94 < 0.01 36.24 30.50 41.98 < 0.01
NO x 27.70 68,303 0.93 0.86 1.00 0.06 25.31 20.84 29.78 < 0.01
NO 17.90 68,303 0.95 0.89 1.02 0.20 20.27 16.23 24.32 < 0.01
CO 0.48 68,303 0.96 0.88 1.04 0.28 22.79 18.23 27.35 < 0.01
PM 10 6.76 68,303 0.94 0.87 1.01 0.09 20.74 16.68 24.79 < 0.01
PM 2.5 5.10 61,623 0.93 0.84 1.02 0.11 26.83 21.56 32.11 < 0.01
O 3 11.50 68,303 1.13 1.02 1.25 0.01 −31.36 −36.82 −25.89 < 0.01
Land Use Regression model predictions (b)
NO 2 9.34 68,303 0.94 0.86 1.02 0.13 16.59 12.01 21.16 < 0.01
NO x 25.24 68,303 0.98 0.91 1.06 0.66 9.42 5.25 13.59 < 0.01
CALINE4 predictions (b)
NO x 5.65 67,043 0.97 0.90 1.04 0.35 14.10 10.29 17.91 < 0.01
CO 0.08 67,043 0.96 0.90 1.04 0.31 15.09 11.27 18.91 < 0.01
PM 2.5 1.36 67,043 0.99 0.92 1.06 0.74 5.94 2.32 9.57 < 0.01
Traffic density, within buffers of different distances around roads (b)
50 m 12.91 68,303 1.00 1.00 1.01 0.52 0.06 −0.21 0.32 0.68
75 m 35.91 68,303 1.01 0.99 1.02 0.24 −0.21 −1.12 0.69 0.64
100 m 53.91 68,303 1.02 1.00 1.05 0.06 −0.51 −2.00 0.97 0.50
150 m 74.30 68,303 1.05 1.01 1.08 0.01 −0.34 −2.43 1.75 0.75
200 m 84.33 68,303 1.05 1.01 1.09 0.01 0.06 −2.29 2.42 0.96
250 m 81.34 68,303 1.04 1.00 1.08 0.05 0.35 −1.95 2.64 0.77
300 m 76.57 68,303 1.02 0.99 1.06 0.21 0.22 −1.67 2.11 0.82
Distance to the nearest road (b)
Freeways 1766.80 68,303 1.04 0.96 1.14 0.35 −7.80 −12.50 −3.09 < 0.01
Major roads 253.05 68,303 0.94 0.87 1.01 0.07 −1.95 −5.42 1.51 0.27
  1. a) Adjusted for maternal age, length of gestation and poverty using smoothing splines and maternal race/ethnicity, insurance, parity, and gender of the infant as categorical variables.
  2. b) The units are parts per million for CO, parts per billion for NO, NO2, NOx, and O3, and μg.m-3 for PM10 and PM2.5. Concentrations are averages, across the pregnancy period, derived from daily 24 h- mean concentrations for NO2, NO, NOx, CO, PM10 and PM2.5 and from daily mean concentrations from 10 am to 6 pm for O3. The unit for traffic density is vehicle number per day/meter. The unit for distance to road is meters.