Table 3 Relationship of risk factors and the prevalence of asthma from the multivariable regression analysis

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