Table 4.

Zero-inflated Poisson model for number of wheezing events in the third and fourth years of life due to prenatal exposure to PAH compounds, fine particulate matter and other potential risk factors

	IRR	P>z	[95% Conf.	Interval]
Poisson portion
Maternal age
<=20 years
20 – 30 years	0.961	0.820	0.682	1.353
>30 years	0.491	0.001	0.317	0.761
Maternal education
Elementary
Secondary	0.888	0.376	0.683	1.155
Higher	1.095	0.502	0.840	1.426
Maternal atopy	1.351	0.000	1.176	1.552
Number of older siblings	1.130	0.021	1.018	1.254
Gender of child	0.873	0.045	0.765	0.997
Damp/mould	1.669	0.000	1.390	2.005
Cord blood PAH-adducts	0.956	0.506	0.836	1.093
Prenatal exposure to fine	1.063	0.397	0.923	1.223
particulate matter
Presence of wheeze in the first two years of life	1.190	0.013	1.037	1.365
Logistic portion	1/OR
Maternal age	0.412	0.017	0.198	0.856
Maternal education	1.560	0.054	0.993	2.452
Maternal atopy	0.995	0.987	0.544	1.859
Number of older siblings	1.142	0.564	0.727	1.765
Gender of child	1.124	0.671	0.656	1.925
Damp/mould	2.102	0.083	0.908	4.865
Cord blood PAH-DNA adducts	0.845	0.551	0.488	1.467
Prenatal exposure to fine particulate matter	1.027	0.922	0.596	1.772
Presence of wheeze in the first two years of life	2.601	0.001	1.486	4.549
Constant	0.361	0.288	0.055	2.368