Table 3.

Results of logistic regression models on respiratory symptoms of students ^* (n = 667).

Dependent variables with only significant risk factors (p < 0.05)	Model coefficient (B)	Standard error	Statistical significance (p)	Odds Ratio (95%CI: lower-upper)
Physician diagnosed chronic pulmonary disease
Industrial zone (ref = school 3 )	0.396	0.150	0.008	1.49 (1.11–1.99)
In family asthma, allergy etc (ref = no )	0.927	0.239	0.0001	2.53 (1.58–4.04)
Gender (ref = female)	0.569	0.260	0.029	1.77 (1.06–2.94)
Wheezing
In family asthma, allergy etc (ref = no )	0.547	0.240	0.022	1.73 (1.08–2.76)
Mother’s job (ref = housewife)	–0.999	0.321	0.002	0.37 (1.01–3.16)
Smoking (ref = no)	0.521	0.208	0.012	1.68 (1.12–2.53)
Physician –diagnosed current asthma
In family asthma, allergy etc. (ref = no )	1.344	0.465	0.004	3.80 (1.53–9.45)
Working status of student (ref = no )	2.168	0.721	0.003	8.74 (2.13–35.92)
Tightness in the chest
Industrial zone (ref = school 3 )	0.450	0.130	0.001	1.57 (1.22–2.02)
Physician –diagnosed bronchitis
Passive smoker (ref = no )	0.465	0.188	0.013	1.59 (1.10–2.30)
Persistent cough with phlegm
Father’s job (ref = retired)	0.586	0.213	0.006	1.79 (1.18–2.72)
Morning cough without infection
Industrial zone (ref = school 3 )	0.592	0.215	0.006	1.81 (1.19–2.75)
Mother’s education (ref = middle school)	–0.650	0.281	0.021	0.52 (0.30–0.90)
Morning phlegm without infection
Smoking (ref = no)	0.581	0.235	0.014	1.79 (1.13–2.83)

ref = reference;

* = All the independent variables in Table 1 and school zones were included in the models.