| BackgroundBronchial asthma (asthma) is a chronic pulmonary disease in which many cells (eosinophils, mast cells, T lymphocytes, neutrophils, dendritic cells, airway epithelial cells) and cellular elements play an important role. The disorder of the airway is characterized by airway hyper responsiveness (AHR), airway inflammation, and airway remodeling. With the effect of industrialized and urbanization, climate change and environmental or ecology pollution, the prevalence rate and mortality of asthma are increasing year by year. Asthma is also a problem in China, with an estimated20million affected individuals. It not only reduces the quality life of individual but also brings the serious burden to the social economic and the family because of the great cost. Therefore, asthma has been the universal subject of prevention. Moreover, the factors that influence the risk of asthma are gradually changing with the ecology and lifestyle. So the epidemiology survey on prevalence and risk factors of asthma in different regions will make great significance on asthma prevention.However, there is not much information on the epidemiological study of asthma in Beijing among the adults, especially lack of the effective prevention and treatment systems about it. The intervention measures and policy were not put into practice because of the deficiency of epidemiological survey data in Beijing. Then a comprehensive study was conducted to investigate the prevalence, risk factors, clinical feature, control level and reality of asthma. A collaboration of Beijing Health Bureau and China Asthma Alliance, provide an excellent platform to the epidemiological survey on prevalence rate and the associated risk factors of asthma in Beijing area (Projects in the Capital medical development scientific research). A cross-sectional study was carried out in this study (February2010to August2011) in Beijing residents among the people who aged more than14years. The multi-stage random cluster sampling methods was applied to obtain study subjects. In this report, the baseline data of the project was used. The author is one of the investigators of the project, responsible for coordination and inspection of the study field and data management and analysis.Objective1. To survey the prevalence rate and risk factors of bronchial asthma in Beijing area among the people who aged more than14years from2010to2011.2. To obtain the clinical feature of asthmatic patients in Beijing area such as clinical syndromes, combinations, triggers and so on.3. To evaluate the current level of asthma control and their insights and self-management from asthmatics and then assess the impaction on quality life of asthmatics.Methods1. Subjects:The people who aged more than14years in Beijing area were the target population of the study. And the objects were obtained by stratified cluster random sampling. The criterion of objects were as follow:(1) The age of the individual was more than14years, male or female;(2) People who had register of Beijing and lived here for no less than2years or those residents who had not registered of Beijing but lived here longer than3years.2. Methods:From February2010to August2011, a cross-sectional study was carried out in this study. The multi-stage random cluster sampling methods was applied to obtain study subjects. The16districts and2counties of Beijing were classified in to three categories as urban (Dongcheng, Xicheng, Xuanwu and Chongwen), suburb (Haidian, Chaoyang, Shijingshan and Fengtai) and outskirt (Tongzhou, Mentougou, Daxing, Fangshan, Changping, Shunyi, Huairou, Pinggu, Miyun and Yanqing). Steps1,2districts or counties were randomly selected in each category. Step2, in each of the2selected districts or counties,1-2towns or street offices were randomly sampled as the target towns or street offices. Step3, in each of the1-2selected towns or street offices,1-2communities or villages were randomly sampled as the target communities or villages in each of the grade from grade1to grade4. Steps4, all of the residents in the selected communities or villages were sampled. Every districts or counties were sampled20000, and the total sample size was about60000. Home visit completion of epidemiological questionnaires was conducted. And the asthmatics were diagnosed based upon case history, clinical signs and lung function test. Then the epidemiological status of Beijing area on prevalence and risk factors were investigated. Detailed epidemiology data on asthma control and reality was collected via face-to-face home visit interviews among the asthmatics so the control level and of asthma was investigated. All of the epidemiological questionnaires were collected and checked. Then they were coded and filed. At last, the questionnaires and their codes were input and checked by the professional person twice so that the data could correctly input.3. Statistical Analysis:The version3.1of Epidata system was used for data entry and the data were analyzed using SAS9.2software package. The General social characteristics of all the participants were described. Minium, Maximum, Means and standard errors were calculated for measurement data. And prevalence rate, relative rate and constituent ratio were calculated for numeration data. Analysis of variance or nonparametric statistics were used to compare statistical differences of variables. Chis-square test or trend chi-square was used to compare statistical differences of prevalence rates. A2-tailed P value less than0.05was considered statistically significant.Results1. In total, sampling population was61107and57647questionnaires were valid actually. Of which687had asthma. Male asthmatics were296and female asthmatics were391. The overall prevalence rate was1.19%(687/57647). The asthma prevalence rates in urban and suburb of Beijing area were1.09%(418/38468) and1.40%(269/19179) respectively and the prevalence rate of asthma in suburb area was significantly higher than that of urban area (χ2=10.850, P=0.001). The asthma prevalence rates in male and female were1.06%(296/27947) and1.32%(391/29700) respectively and the prevalence rate of asthma in female was much higher than that of male (χ2=8.098, P=0.004). There was a significant difference among different age groups (χ2=404.874, P <0.005). The asthma prevalence rates in urban and suburb of Beijing area were highly increased by1.12and2.26times respectively than that of2002.2. The risk factors associated with asthma may be female, active smoking, obesity, combination of allergic rhinitis, diagnosis of pneumonia, bronchitis/bronchiolitis, tuberculosis, allergy rhinitis, eczema, and direct relatives diagnosed of asthma and living in the suburb.255asthmatics were attacked or aggravated by some triggers which accounted for37.1%in all asthma patients. Patients-reported asthma triggers were exposure to cold air (154/687), climate change (141/687), irritant gas (120/687), catching a cold (111/687), tired (75/687), exercise (67/687), stress or nervous (56/687) and smoking (55/687).3. A total of687asthmatic patients were detected in this survey with a mean age of (60.7±16.5) years and disease duration of (20.8±17.3) years.198asthmatics were first diagnosed in this survey which accounted for28.8%(198/687) in all asthma patients that were diagnosed in the survey.15.0%(103/687) asthmatics were diagnosed as asthma when they were in their childhood before14years. The severe symptoms that the asthmatics self-reported when they episodes were wheeze (383/687), shortness of breath (167/687) and dyspnea (154/687). The predominant symptoms that the asthmatics self-reported were wheeze (557/687) followed by dyspnea (497/687) and cough (484/687). The smoking rate of asthmatic patients was31.9%(219/687). The asthmatics who had a complication of allergic rhinitis, eczema, allergy conjunctivitis or GRED were accounted for32.9%,9.3%,5.5%and4.4%respectively.4. In this study, according to the ACT test,34.9%(240/687) of the asthmatics in Beijing area had complete control,39.2%(269/687) had partially control and25.9%(178/687) had poorly controlled asthma. In the past year,21.3%(146/687) of patients reported emergency room visit at least one time within the past year due to asthma exacerbation and14.0%(96/687) had been hospitalized because of sudden attacks.13.5%(93/687) of the asthmatics knew that the intrinsic feature of asthma was inflammation and5.1%(104/687) of the asthmatics understood the treatment goal of this disease. Only12.1%(83/687) patients used inhaled corticosteroids regularly.71.2%(489/687) asthmatics had never undergone a lung functional test in the past year.12.3%(84/687) had a device for peak flow meter of their own but only1.5%(10/687) monitored peak flow regularly.46.6%(320/687) asthmatics reported that their activities including entertainment, learning, fertility and employment were limited due to asthma, Even3.6%(25/687) had mind of suicide.Conclusions1. The prevalence rate of asthma in urban and suburb are highly increased than ten years ago and it posed urgent situation to us. The prevalence rate of asthma in suburb area was significantly higher than that of urban area and the prevalence rate of asthma in female was much higher than that of male. There are significant different prevalence rates between different ages, occupations and education level but There is no differences between Han and Non-Han race.2. There are many kinds of associated risk factors of asthma. Host factors such as atopy, sex, obesity and environmental factors included history of smoking, respiratory tract infection disease in childhood included pneumonia, bronchitis/bronchiolitis, tuberculosis and living in the suburb.255asthmatics were attacked or aggravated by some triggers which accounted for37.1%in all asthma patients. Patients-reported asthma triggers were exposure to cold air, climate change irritant gas, catching a cold, tired, exercise, stress or nervous and smoking.3.687asthmatics were detected and198asthmatics were first diagnosed in this survey which accounted for28.8%in all asthma patients that were diagnosed in the survey. The severe symptoms that the asthmatics self-reported when they episodes were wheeze, shortness of breath and dyspnea The predominant symptoms that the asthmatics self-reported were wheeze followed by dyspnea and cough. The asthmatic patients who had history of smoking was accounted for31.9%. The asthmatics who had a complication of allergic rhinitis, eczema, allergy conjunctivitis or GRED were accounted for32.9%,9.3%,5.5%and4.4%respectively.4. In this study,34.9%of the asthmatics in Beijing area had complete control,39.2%had partially control and25.9%had poorly controlled asthma. The level of asthma control in Beijing area has been improved greatly but it still falls down far below the GINA goals and there were also many times of emergency room visits and hospitalizations of asthmatics in Beijing area in the last year. The level of self-monitoring and insight about the disease among the asthmatics were very low. Activity limited, psychological and social functions were largely impacted by the disease because of the uncontrolled asthma. Therefore it is necessary to educate the asthmatics, guide the patients to the long-term management and standardized therapy and avoid the cause and the triggers of asthma. And then the times of exacerbations of asthma would be reduced and thus the life quality of asthmatics would be improved and the burden of this disease on society would be reduced. |
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