Respiratory symptoms in children living near busy roads and their relationship to vehicular traffic: results of an Italian multicenter study (SIDRIA 2)

Table 4 Associations between traffic indicators and asthma symptoms with or without cough or phlegm.

	Asthma symptoms WITHOUT cough or phlegm				Cough or phlegm WITHOUT asthma symptoms				Asthma symptoms WITH cough or phlegm
	n cases	(%)	OR*	95% CI	n cases	(%)	OR*	95% CI	n cases	(%)	OR*	95% CI
Traffic density
Absent	465	10.3	1.00		171	3.8	1.00		99	2.2	1.00
Low	996	10.2	1.00	0.89–1.13	326	3.4	0.83	0.69–1.00	232	2.4	1.12	0.88–1.42
Moderate	1,083	10.9	1.08	0.95–1.22	397	4.0	0.92	0.75–1.11	292	2.9	1.27	1.02–1.57
High	601	11.0	1.13	0.99–1.28	281	5.2	1.14	0.92–1.41	194	3.6	1.52	1.17–1.96
Frequency cars transit
Never	254	10.5	1.00		87	3.6	1.00		55	2.3	1.00
Sometimes	938	9.9	0.93	0.80–1.07	308	3.3	0.91	0.72–1.15	209	2.2	0.97	0.71–1.34
Frequently	1,129	11.0	1.03	0.89–1.19	409	4.0	1.07	0.83–1.36	270	2.6	1.10	0.80–1.52
Continuously	823	11.0	1.07	0.92–1.25	371	5.0	1.30	1.02–1.67	285	3.8	1.53	1.11–2.10
Frequency trucks transit
Never	1,158	10.1	1.00		398	3.5	1.00		254	2.2	1.00
Sometimes	1,299	10.8	1.07	0.98–1.17	467	3.9	1.10	0.95–1.26	345	2.9	1.27	1.09–1.48
Frequently	525	11.1	1.13	1.01–1.26	242	5.1	1.44	1.23–1.69	157	3.3	1.51	1.21–1.87
Continuously	150	11.2	1.21	1.01–1.46	71	5.3	1.47	1.13–1.93	61	4.5	2.11	1.58–2.81

* All ORs were adjusted for study centre, age, sex, parental asthma or allergies, parental education, passive smoke at home, indoor moulds, season, person filling the questionnaire, floor level of the apartment and change of residence.

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