The relationship between smoking status and epidermiology of asthma in people aged over 14 years in China

Abstract

Objective: To study the relationship between bronchial asthma and smoking status in Chinese people. Methods: Asthma epidemiological survey and stratified-cluster-random method survey were performed in residents over 14 years in 8 provinces (cities) of China from February 2010 to August 2012. Asthma was diagnosed based upon case history, clinical signs and lung function test. Smoking status was investigated by questionnaire. Results: Sampling population was 180 099 and 164 215 were valid. A total of 2 034 subjects were diagnosed as asthma including 79 692 men and 84 523 women. The overall prevalence rate of asthma was 1.24% (2 034/164 215). Smokers were 23.8% (39 137/164 215) in the whole population. Smokers were 34.5% (702/2 034) in asthmatic patients, compared with 23.7% (38 435/162 181) in no-asthmatic population. The incidence of asthma was 1.79% and 1.06% in smokers and non-smokers respectively (P<0.001), suggesting that OR of smoking was 1.70 (95% CI 1.55-1.86, P<0.001). According to asthma control test (ACT) score, the level of asthma control in non smoking group was higher than that in smoking group(43.2% vs 35.3%). The times of hospitalization due to acute exacerbations(0.51 vs 0.41 events/person/year), total hospitalization rate(27.35% vs 20.12%), annual emergency room visits (0.80 vs 0.60 events/person/year) and emergency room visit rate (31.77% vs 24.47%) were all much higher in smoking asthmatic patients than those in non smoking asthmatic patients, indicating that the level of asthma control in smoking patients was significantly worse than in non smoking patients. Conclusions: The smoking rate in Chinese people over 14 years is still high. The prevalence rate of asthma in smokers is significantly higher than that of non-smokers. The level of asthma control in smokers is significantly worse than that in non smokers.