Table 3.

Relationship of risk factors and the prevalence of asthma from the multivariable regression analysis

Risk factor	OR (95% CI)	P
Race
Han (reference)	1.00	.
Minorities	1.55 (1.12–2.14)	0.008
Age
45–49 years (reference)	1.00	.
50–59 years	1.24 (0.77–1.98)	0.374
60–69 years	1.85 (1.17–2.92)	0.008
≥ 70 years	2.63 (1.66–4.17)	< 0.001
Education
High-school or above (reference)	1.00	.
Middle-school	1.88 (1.15–3.05)	0.011
Primary education	2.48 (1.55–3.98)	< 0.001
Literate	2.53 (1.57–4.07)	< 0.001
Illiterate	2.78(1.72–4.49)	< 0.001
Geographic region
East (reference)	1.00	.
North	1.52 (1.11–2.09)	0.010
Northeast	0.86 (0.52–1.40)	0.532
Northwest	1.71 (1.18–2.49)	0.005
South Central	1.02 (0.76–1.37)	0.885
Southwest	1.16 (0.85–1.56)	0.349
Smoking status
Non-smokers (reference)	1.00	.
Smokers	1.37 (1.11–1.68)	0.003
Type of cooking
Clean (reference)	1.00	.
Unclean	1.07 (0.86–1.32)	0.564

These variables with a P < 0.05 in univariate comparison were included in the multivariate logistic regression analysis

OR odds ratio, CI confidence interval