Table 1 Associated factors regarding asthma by univariate logistical regression models

Demographic and socioeconomic characteristics

Age (years)

5-6 (2543, 12.3%)

101 (4.0)

1.86 (1.36-2.56)

7- (3802, 18.4%)

141 (3.7)

1.73 (1.28-2.34

8- (3839, 18.6%)

128 (3.3)

1.55 (1.15-2.10)

9- (3798, 18.4%)

131 (3.4)

1.61 (1.19-2.18)

10- (3724, 18.0%)

134 (3.6)

1.68 (1.24-2.27)

11- (2943, 14.3%)

64 (2.2)

Ref.

Gender (%)

Boys (10227, 49.5%)

434 (4.2)

1.67 (1.44-1.96)

Girls (10445, 50.5%)

269 (2.6)

Ref.

Ethnicity

Han ethnic group (19604, 94.9%)

674 (3.4)

1.40 (0.94-2.08)

Minority ethnic group (1030, 5.1%)

26 (2.5)

Ref.

Family income

<800 (3956, 19.3%)

67 (1.7)

Ref.

800-2500 (11612, 56.6%)

344 (3.0)

1.77 (1.36-2.31)

≥2500 (4966, 24.2%)

284 (5.7)

3.52 (2.69-4.61)

Family structure

Single parent family (1103, 5.3%)

41 (3.7)

1.17 (0.85-1.63)

Large family (6565, 31.7%)

249 (3.8)

1.20 (1.02-1.41)

Nuclear family (13014, 62.9%)

413 (3.2)

Ref.

Mather’s education level

Low (5752, 28.2%)

118 (2.1)

Ref.

Medium (6825, 33.4%)

204 (3.0)

1.47 (1.17-1.85)

High (7843, 38.4%)

370 (4.7)

2.37 (1.92-2.92)

Father’s education level

Low (4940, 23.9%)

109 (2.2)

Ref.

Medium (7075, 34.2%)

215 (3.0)

1.39 (1.10-1.76)

High (8647, 41.8%)

379 (4.4)

2.03 (1.64-2.52)

General chronic health problems

Overweight/obesity

Obesity (1323, 8.2%)

58 (4.4)

1.44 (1.08-1.91)

Overweight (2206, 13.6%)

91 (4.1)

1.35 (1.07-1.71)

Normal (12656, 78.2%)

391 (3.1)

Ref.

Food/drug allergy

Yes (1176, 5.7%)

139 (11.8)

4.53 (3.72-5.51)

No (19588, 94.3%)

565 (2.9)

Ref.

Gastro-oesophageal reflux

Yes (159, 0.8%)

19 (11.9)

3.97 (2.44-6.45)

No (20609, 99.2%)

686 (3.3)

Ref.

Respiratory diseases

History of chronic allergic rhinitis diagnosis

Yes (1993, 9.6%)

310 (15.6)

8.65 (7.39-10.12)

No (18764, 90.4%)

392 (2.1)

Ref.

Upper respiratory infection

Frequently (3607 17.4%)

350 (9.7)

5.09 (4.37-5.93)

Occasionally (17164, 82.6%)

355 (2.1)

Ref.

History of hypertrophy of tonsils diagnosis

Yes (2369, 11.4%)

123 (5.2)

1.68 (1.38-2.05)

No (18404, 88.6%)

582 (3.2)

Ref.

Symptoms of sleep disordered breathing

Habitual snoring

Usually/Often (2525, 12.2%)

160 (6.3)

2.20 (1.83-2.64)

Occasionally/No (18234, 87.8%)

544 (3.0)

Ref.

Stops breathing

Usually/Often (282, 1.4%)

24 (8.5)

2.71 (1.77-4.15)

Occasionally/No (20419, 98.6%)

677 (3.3)

Ref.

Snorts and gasps

Usually/Often (640, 3.1%)

80 (12.5)

4.47 (3.49-5.72)

Occasionally/No (20071, 96.9%)

622 (3.1)

Ref.