| BackgroundBronchial asthma (asthma) is a chronic inflammatory airway disease in which many cells (such as eosinophils, mast cells, T lymphocytes, neutrophils, smooth muscle cells, airway epithelial cells) and cellular elements was involved. The disorder of the airway is characterized by chronic airway inflammation, airway hyperresponsiveness to various stimuli presented, reversible airflow limitation and a series changes of airway structure with the duration of disease caused which was called airway remodeling. The treatment not only consumes a large number of countries health resources, but also results in serious social and economic burden due to labor loss. With the development of global industrialization, the morbidity of asthma is increasing year by year, with an estimated20million affected individuals in China. There are about5-10%of patients who is still not well controlled after they were treated with the standard therapy. All these cases are called difficult asthma, although the proportion is not high, but it is an important reason for increasing costs of asthma. As everyone knows, there are many risk factors which are related to asthma and exacerbate the symptoms of asthma, and some risk factors have different effect on different individuals and different growth stages of individuals. Therefore, to explore the related risk factors of asthma is a milestone for the prevention and management of asthma in the future. But there is lack of large-scale epidemiological investigation on asthma prevalence and risk factors in China. Epidemiology survey on prevalence and risk factors of asthma will make great significance on the treatment and prevention of asthma. This situation has become the shackles of improving the level of the prevention and management of asthma, which also is an obstacle to formulate relevant health policies in order to make rational use of health resources.A comprehensive study was conducted to investigate the prevalence, risk factors, clinical feature, control level and reality of asthma, difficult asthma and special type of asthma. With the excellent platform we perform the epidemiological survey on China Asthma and Risk factors Epidemiologic investigation (Chinese Medical Association funds research special clinical medicine Projects in the Capital medical development scientific research). A cross-sectional study was carried out in this study (February2010to August2011) in Beijing, Shanghai, Guangdong, Liaoning, Henan, Shanxi, Jiangsu, Sichuan residents among the people who aged more than14years. The multi-stage random cluster sampling methods was applied to understand the epidemiological characteristics of asthma and provide scientific basis for prevention and control. 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 of bronchial asthma in China among the people who aged more than14years in order to to understand the epidemic trend of asthma.2. To obtain the associated with asthma risk factors and the distribution characteristics of risk factors in China.3. To understand the aggravating factors and the features of clinical symptoms of asthma in China.4. To evaluate the current status of asthma control and their insights and self-management of asthmatics and then assess the effect on on quality life of asthmatics.Methods1. Subjects:(1)the target population:According to the division of administrative regions in China which include north, northeast, southern china, east, south, southwest and northwest in the7regions, we selected for one province (city) or two in order to carry on epidemiology survey on the prevalence and associated risk factors of asthma. The people who aged more than14years in eight areas (Beijing, Shanghai, Guangdong, Liaoning, Henan, Shanxi, Jiangsu, Sichuan provinces (cities)) were the target population of the study. And the objects were obtained by stratified cluster random sampling.(2)The criterion of objects were as follow:①The age of the individual was more than14years, male or female;②People who had register of local areas and lived here for no less than2years or those residents who had not registered of local areas but lived here longer than3years.2. Methods:The multi-stage random cluster sampling methods was applied to obtain study subjects in8provinces (cities). Steps1,2districts or3counties were randomly selected in each category. Step2, in each of the selected districts or counties,2towns or street offices were randomly sampled as the target towns or street offices. Step3, in each of the selected towns or street offices,2communities or villages were randomly sampled Steps4, all of the residents in the selected communities or villages were sampled. Every province or city was sampled12000according to the prevalence rate of1.5%calculated, and the total sample size was about180000.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 eight areas 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 SPSS12.0software 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.2-tailed P value less than0.05was considered statistically significant.Results1. Sampling population was180099and164215questionnaires were effective actually, of which2034had asthma. Male were79692and female were84523. The overall prevalence rate was1.24%(2034/164215). In different region, age, nationality, occupation and level of education people there are difference in the prevalence of asthma.2. Correlation analysis of risk factors showed that smoking (OR=1.70,95%CI:1.55-1.86), breast feeding (OR=0.80,95%CI:0.67-0.96), genetic factors (OR and corresponding95%CI were greater than1, asthma is the most significant (OR=10.44,95%CI:8.99-12.11), complications (OR and95%CI were greater than1), body mass index(compared with normal weight, overweight(OR=1.36,95%CI:1.21-1.53), obesity (OR=10.63,95%CI:9.57-11.80)), pet (OR and the corresponding95%CI is more than1).3. Patients-reported asthma triggers were catching a cold, climate change,exposure to cold air, tired, irritant gas, stress or nervous, contact or inhalation of dust, smoking, exercise and house dust. The severe symptoms that the asthmatics reported when they episodes were wheezes, shortness of breath and dyspnea. The predominant symptoms that the asthmatics reported were wheeze, followed by dyspnea, cough and shortness of breath.4. A total of2034asthmatic patients were detected in this survey with a mean age of (56+18) years. In this study, according to the ACT test15.63%(318/2034) of the asthmatics had complete control,49.46%(1006/2034) had partially control and34.91%(710/2034) had poorly controlled asthma. In the past year,27.00%(549/2034) of patients reported emergency room visit at least one time within the past year due to asthma exacerbation and22.62%(460/2034) had been hospitalized because of sudden attacks.22.42%(456/2034) of the asthmatics knew that the intrinsic feature of asthma was inflammation and14.85%(302/2034) of the asthmatics understood the treatment goal of this disease. Only14.75%(300/2034) patients used inhaled corticosteroids regularly.22.71%(462/2034) asthmatics had undergone a lung functional test in the past year.12.83%(261/2034) had used peak flow meter of their own only in the exacerbation of the disease, but only1.62%(33/2034) monitored peak flow regularly.59.64%(1213/2034) asthmatics reported that their activities including entertainment, learning, fertility and employment were limited due to asthma, Even3.98%(81/2034) had mind of suicide.Conclusions1. The prevalence rate of asthma is1.24%in China.The prevalence rate of asthma in China increased significantly compared with before in some areas.2. There are many kinds of associated risk factors of asthma. Host factors such as genetic factors, obesity and environmental factors included history of smoking, breastfeeding, comorbidity, pets and other factors.3. The survery found:(1)Patients-reported asthma triggers were exposure to irritant gas, catching a cold, climate change, cold air, tired, stress or nervous, contact or inhalation of dust, smoking, exercise and house dust.(2)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, cough and shortness of breath.(3)Smoking rates of asthmatics are higher than in the general population.(4)The most common complications is allergic rhinitis, GERD, COPD and so on.4. In this study,(1)The rate of asthma control is relatively lower in China. It still falls down below the GINA goals (2)The patients who can understand correctly the nature and goals of treatment are lower.(3)The levels of management of asthma in China are lower which include the use of rate of standardized medicine, regular follow-up and monitoring and so on.(4)The levels of quality of life are lower which include have activity limition of nearly half of patients, emotion affected of many patients, even to commit suicide. |
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