. Author manuscript; available in PMC: 2018 Sep 1.

Published in final edited form as: Ann Allergy Asthma Immunol. 2017 Jul 27;119(3):232–237.e1. doi: 10.1016/j.anai.2017.06.016

Table 2.

Interaction models and stress-stratified associations between prenatal PM_2.5 concentrations and wheeze outcomes and RRs shown for an average pregnancy IQR (3.8 μg/m³) increase in PM_2.5. Models adjusted for child’s sex, maternal asthma, maternal age at delivery, prenatal ETS exposure, ETS exposure at 48 months of age, other trimester PM_2.5 concentrations and postnatal year 1 average PM_2.5.

	RR (95% CI)
	Low Stress (≤3) Stratum N=349	High Stress (>3) Stratum N=203	Combined data N=552

			p-value for interaction between PM_2.5 and stress
Ever Wheeze
1^st trimester PM_2.5	0.99 (0.83, 1.18)	1.18 (0.97, 1.43)	0.19
2^nd trimester PM_2.5	0.92 (0.76, 1.12)	1.06 (0.85, 1.32)	0.32
3^rd trimester PM_2.5	0.96 (0.82, 1.13)	0.94 (0.78, 1.15)	0.66
Current wheeze
1^st trimester PM_2.5	0.84 (0.61, 1.16)	1.35 (1.00, 1.83)	0.04
2^nd trimester PM_2.5	0.74 (0.54, 1.04)	0.99 (0.71, 1.38)	0.22
3^rd trimester PM_2.5	0.96 (0.74, 1.26)	0.83 (0.61, 1.13)	0.28

Abbreviations: CI, confidence interval; RR, relative risk.