Table 4.

Crude and adjusted odds ratios (OR) with 95% confidence intervals (CI) for the association between the explanatory factors and childhood asthma

Explanatory factors	Crude OR	95% CI	Adjusted OR*	95% CI
Sex:
male	1	reference	1	reference
female	0.71	0.47-1.05	1.16	0.72-1.86
Age group (years):
0-4	1	reference	1	reference
5-9	2.79	1.56-5.01	2.52	1.28-4.95
10-14	1.79	0.99-3.24	1.62	0.82-3.18
≥15	1.22	0.58-2.55	0.83	0.36-1.94
Maternal occupational:
blue-collar worker	1	reference	1	reference
white-collar worker	2.53	0.90-7.12	2.22	0.74-6.71
out of work	2.97	1.05-8.37	3.40	1.11-10.4
Family situation:
complete family	1	reference	1	reference
incomplete family	2.24	1.37-3.67	1.78	0.98-3.23
Threatening preterm labor in the index pregnancy:
no	1	reference	1	reference
yes	1.88	1.07-3.30	1.20	0.61-2.38
Birth weight (g):
≤2500	1	reference	1	reference
2501-3000	1.87	0.41-8.43	1.48	0.30-7.30
3001-3500	1.66	0.39-7.04	1.26	0.28-5.78
3501-4000	2.45	0.57-10.6	1.73	0.37-8.16
>4000	3.46	0.74-16.2	1.90	0.37-9.82
unknown	2.08	0.44-11.1	3.29	0.52-20.9
History of breastfeeding:
never breastfed	1	reference	1	reference
any breastfed	0.41	0.25-0.68	0.71	0.39-1.30
Allergies in infancy:
no	1	reference	1	reference
yes	2.13	1.41-3.21	1.62	1.00-2.61
First bronchitis and/or pneumonia in infancy:
no	1	reference	1	reference
yes	15.09	9.28-24.54	12.21	7.29-20.45
Self-reported parental allergies:
none	1	reference	1	reference
one parent	4.79	3.13-7.34	3.55	2.16-5.82
both parents	9.94	4.88-20.3	7.14	2.99-17.0

*Adjusted for all variables in the table.