Skip to main content

Table 1 Statistics for the means of the target and individual-level variable across Census tracts

From: Spatial variability of the effect of air pollution on term birth weight: evaluating influential factors using Bayesian hierarchical models

Type Variable Category Mean Median Inter quartile range (IQR)a
Target variable Term birth weight (g)   3393 3392 58 (3363,3421)
Pollution indicator Spatiotemporal NO2 (ppb)b   25.00 24.14 11.43 (18.74, 30.17)
Spatiotemporal NOx (ppb)c   17.32 26.31 31.32 (15.48, 46.80)
Individual- level variable NDVI   0.26 0.25 0.09 (0.21, 0.30)
Maternal age   28.8 28.1 4.1 (26.7, 30.8)
Length of gestation   277 276 12 (271,283)
Infant gender (percentage) Male 49 % 49 % 6 % (46–52 %)
Female 51 % 51 % 6 % (48–54 %)
Race/ethnicity (percentage) Hispanic 54 % 57 % 57 % (26–83 %)
White 24 % 12 % 43 % (2–45 %)
Black 6 % 3 % 5 % (0.8–6 %)
Asian 13 % 8 % 14 % (2–16 %)
Others 2 % 1 % 2 % (1–3 %)
Maternal educational level (percentage) Less than 8th grade 10 % 8 % 15 % (1–16 %)
9th grade to high school 42 % 47 % 36 % (24–60 %)
Less than 4 years of college 29 % 20 % 43 % (6–49 %)
4+ of college 19 % 19 % 11 % (13–24 %)
  1. aIQR for the mean (continuous variables) or percentage (categorical variables);
  2. bEstimates of NO2 by the spatiotemporal model; cEstimates of NOx by the spatiotemporal model