Table 3.

Crude and adjusted associations between wildfire smoke PM_2.5 (µg/m³) exposure and preterm births.

	Crude Model		Adjusted Model *
	OR (95% CI)	p-Value	OR (95% CI)	p-Value
First Trimester	0.972 (0.950, 0.995)	0.019	1.024 (0.986, 1.065)	0.22
Second Trimester	1.058 (1.034, 1.082)	<0.0001	1.132 (1.088, 1.178)	<0.0001
Third Trimester	0.949 (0.930, 0.969)	<0.0001	1.013 (0.978, 1.050)	0.47
Mean Over All Trimesters	0.992 (0.980, 1.004)	0.19	1.055 (1.033, 1.078)	<0.0001
Full Gestation	0.972 (0.938, 1.006)	0.11	1.076 (1.016, 1.139)	0.013

* Model adjusted for: Ozone, non-wildfire PM_2.5, PM₁₀, temperature deviation, month, year, mother’s race/ethnicity, mother’s education and income, mother’s age, smoking during pregnancy, drinking during pregnancy, maternal asthma, and gindex.