[Epidemiological survey of asthma in a rural area of Yanqing County in Beijing].

Objective: To evaluate the epidemiology and risk factors of asthma of people aged more than 40 years living in the rural area of Beijing.

Methods: The data of 1,638 people aged more than 40 years living in 5 villages of Yanqing County in Beijing were collected. Respiratory symptoms, the living conditions, life styles and cooking habits, personal history and family history were collected. Physical examination and lung function tests (ventilation function and bronchodilation tests) were also performed. Asthma was diagnosed based on symptoms, signs, and lung function tests. Univariate analysis and Logistic analysis were employed to evaluate the risk factors for asthma.

Results: The prevalence of asthma was 1.89% (31/1 638). For those with asthma, the male to female ratio was 1:4.2, the difference being significant (P<0.05). Common triggering factors for asthma included influenza, cold air, passive smoking and cooking oil smoke. There were statistic differences between asthmatics and non-asthmatics in respiratory disease history in childhood, frequent cough before age 14, and years of exposure to biomass fuel. Cough before age 14 was closely associated with asthma. Only 12.9% of the cases had been diagnosed before this study, indicating that asthma was a underdiagnosed disease in this area.

Conclusion: The prevalence of asthma is high in this rural area of Beijing. Life style changes and management of respiratory infections before age 14 are indicated for reducing risk factors for asthma. More attention should be paid to early diagnosis of asthma in rural areas.