Table 2.

Odds ratios (OR) and 95% confidence intervals for autism, by quartile^** of modeled traffic related air pollution (TRP) exposure from all road types (N=524).

		4th quartile	3rd quartile	2nd quartile
First Year of Life	Crude	2.97 (1.71–5.27)	1.00 (0.63–1.60)	0.88 (0.55–1.42)
	Adjusted*	3.10 (1.76–5.57)	1.00 (0.62–1.62)	0.91 (0.56–1.47)
All Pregnancy	Crude	1.99 (1.22–3.28)	1.10 (0.67–1.78)	1.20 (0.74–1.95)
	Adjusted*	1.98 (1.20–3.31)	1.09 (0.67–1.79)	1.26 (0.77–2.06)
First Trimester	Crude	1.91 (1.67–3.14)	1.28 (0.80–2.06)	1.28 (0.77–2.14)
	Adjusted*	1.85 (1.11–3.08)	1.28 (0.79–2.08)	1.28 (0.77–2.15)
Second Trimester	Crude	1.69 (1.04–2.78)	1.15 (0.71–1.87)	0.89 (0.54–1.47)
	Adjusted*	1.65 (1.00–2.74)	1.13 (0.69–1.84)	0.90 (0.54–1.49)
Third Trimester	Crude	2.04 (1.25–3.38)	0.92 (0.57–1.48)	1.12 (0.68–1.84)
	Adjusted*	2.10 (1.27–3.51)	0.91 (0.56–1.46)	1.17 (0.71–1.93)

^*Model adjusted for child male gender, child ethnicity (Hispanic vs. White, Black/Asian/Other vs. White), maximum education of parents (parent with highest of four levels: college degree or higher vs. some high school, high school degree, or some college education), maternal age ( >35 years vs. ≤ 35years), and prenatal smoking (self report of ever vs. never smoked while pregnant).

^**Quartile cut points correspond to TRP levels of 31.8 ppb or greater (4^th quartile), 16.9–31.8 ppb (3^rd quartile), and 9.7–16.9 ppb (2^nd quartile), compared to 9.7 ppb or less (1^st quartile, reference group).