Characteristics of the Singapore Chinese Health Study never smokers
| Characteristic | No cough, phlegm or asthma(N = 31142) | Recent cough and/or phlegm(N = 1320) | Asthma diagnosis(N = 1504) | Chronic bronchitis*(N = 149) | Chronic phlegm without cough(N = 700) | Chronic dry cough(N = 185) | Total subjects†(N = 35000) |
|---|---|---|---|---|---|---|---|
| *Chronic bronchitis was defined as combined chronic cough and phlegm. | |||||||
| †Total includes all 35 000 non-smoking subjects. | |||||||
| ‡Number of smokers for childhood and adult ETS exposure is a semi-quantitative variable representing the minimum number of smokers. | |||||||
| §Some percentages do not add up to 100 because of rounding. | |||||||
| % of total† | 89.0 | 3.8 | 4.3 | 0.4 | 2.0 | 0.5 | 100 |
| % female | 77.3 | 72.4 | 77.0 | 65.1 | 68.7 | 68.1 | 76.8 |
| Mean (SD) age (years) | 60.7 (7.8) | 61.5 (8.1) | 60.2 (7.8) | 62.1 (8.0) | 60.1 (7.9) | 60.7 (7.4) | 60.7 (7.8) |
| Hokkien or Cantonese dialect | |||||||
| % Hokkien | 49.8 | 37.3 | 52.5 | 55.7 | 44.3 | 59.5 | 49.4 |
| Childhood ETS exposure (%) | |||||||
| None | 35.4§ | 29.5 | 31.4§ | 24.2 | 26.1 | 19.5 | 34.7§ |
| 1 smoker ‡ | 34.0 | 35.8 | 34.2 | 39.6 | 35.1 | 40.5 | 34.2 |
| 2 smokers | 21.4 | 24.1 | 24.1 | 22.1 | 25.9 | 27.6 | 21.7 |
| 3+ smokers | 9.3 | 10.6 | 10.2 | 14.1 | 12.9 | 12.4 | 9.5 |
| Adult ETS exposure (%) | |||||||
| Home | |||||||
| None | 27.7 | 23.1 | 24.5§ | 14.1§ | 21.1 | 20.5§ | 27.2 |
| Past | |||||||
| 1 smoker | 30.7 | 32.0 | 28.3 | 35.6 | 34.7 | 35.7 | 30.8 |
| 2+ smokers | 21.4 | 23.6 | 24.9 | 26.2 | 23.6 | 27.6 | 21.7 |
| Current | |||||||
| 1 smoker | 17.7 | 18.6 | 19.9 | 19.5 | 17.0 | 14.1 | 17.8 |
| 2+ smokers | 2.5 | 2.7 | 2.5 | 4.7 | 3.6 | 2.2 | 2.5 |
| Work | |||||||
| None | 78.1 | 72.2 | 73.1 | 66.4§ | 66.4§ | 67.0 | 77.3 |
| Past | 17.7 | 23.1 | 21.4 | 29.5 | 25.4 | 26.5 | 18.3 |
| Current | 4.2 | 4.7 | 5.5 | 4.0 | 8.1 | 6.5 | 4.4 |