Table 1 Characteristics of the study population of 4530 students at 22 schools in greater Wuhan, China
Characteristic | % |
|---|---|
Subjects | Â |
Age (mean, SD) in years | 13.6, 0.7 |
Gender | Â |
Male Female | 52.5 47.5 |
Respiratory symptoms | Â |
Wheezing with colds | 19.4 |
Wheezing without colds | 7.1 |
Bringing up phlegm with colds | 16.7 |
Bringing up phlegm without colds | 5.7 |
Coughing with colds | 24.7 |
Coughing without colds | 4.5 |
Exposures | Â |
Smokers in child's household | Â |
No smokers 1 smoker 2+ smokers Father smokes Mother smokes Personal smoking by students | 26.8 62.3 10.9 69.1 3.6 0.6 |
Exposure to coal burning | Â |
No coal use Coal used only for heating Coal used only for cooking Coal used for cooking and heating | 54.2 8.8 25.9 11.1 |