Variables | Mean | Std. Dev. | Min-Max | PM 2.5 mean (SE)b | |
---|---|---|---|---|---|
 |  |  |  | Absence/1st quintile | Presence/5th quintile |
Level-1 (individual) | Â | Â | Â | Â | Â |
 Birth weight (grams) | 3433.3 | 566.51 | 135 – 6475 | 7.30 (.016) | 7.36 (.018)c,e |
 Gestational age (weeks) | 38.8 | 2.02 | 19 – 44 | 7.30 (.016) | 7.30 (.017)f |
 Maternal age (years) | 29.8 | 5.60 | 11 – 55 | 7.10 (.022) | 7.39 (.014)c |
 Nulliparous | 0.45 | 0.50 | 0 – 1 | 7.27 (.016) | 7.34 (.016)c |
 Gestational diabetes | 0.06 | 0.25 | 0 – 1 | 7.29 (.016) | 7.53 (.016)c |
 Pre-existing diabetes | 0.004 | 0.06 | 0 – 1 | 7.30 (.016) | 7.34 (.034) |
 Gestational hypertension | 0.02 | 0.15 | 0 – 1 | 7.30 (.016) | 7.44 (.019)c |
 Poor prenatal care | 0.09 | 0.29 | 0 – 1 | 7.28 (.016) | 7.47 (.02)c |
 Drug/Alcohol flag | 0.02 | 0.15 | 0 – 1 | 7.31 (.016) | 7.08 (.026)c |
 Cigarettes/day | 0.79 | 2.91 | 0 – 20 | 7.33 (.015) | 7.02 (.023)c,g |
 Fall/Winter season | 0.48 | 0.50 | 0 – 1 | 7.29 (.016) | 7.31 (.016)c |
Level-2 (DA) variables | Â | Â | Â | Â | Â |
 SESi | -0.08 | 0.58 | -2.22 – 1.18 | 7.82 (.027) | 6.95 (.032)c,d |
 Higher education | 0.50 | 0.12 | 0 – 0.95 | 7.16 (.04) | 7.53 (.022)c,d |
 Immigrant density | 0.16 | 0.19 | 0 – 0.86 | 6.75 (.023) | 7.95 (.021)c,d |
 Rural address | 0.11 | 0.32 | 0 – 1 | 7.39 (.014) | 6.59 (.061)c,d |
 PM2.5 (μg/m3) | 7.30 | 0.86 | 4.41 – 10.23 | -- | -- |