[The prevalence and risk factors of bronchiectasis in residents aged 40 years old and above in seven cities in China].

OBJECTIVE: To investigate the prevalence and risk factors of bronchiectasis in urban city of China. METHODS: A cross-sectional survey was conducted in 17 urban areas in Beijing, Shanghai, Tianjin, Chongqing cities, and Guangdong, Liaoning, Shanxi provinces. In this study, urban population-based cluster samples were randomly selected from each city/province. In the selected city communities, all residents at least 40 years old were recruited, interviewed with questionnaires and tested with spirometry. Each participant was asked whether he/she was ever diagnosed as bronchiectasis by physician, whether had symptoms of respiratory diseases and possible risk factors, etc. RESULT: Data of 10 811 participants was enrolled for analysis, with a response rate of 75.4% (10 811/14 337). The overall prevalence of physician-diagnosed bronchiectasis was 1.2% (135/10 811), with 1.5% (65/4382) in male and 1.1% (70/6429) in female, without statistical difference in gender (χ² = 3.289, P = 0.070). Prevalence of bronchiectasis increased with age (χ² = 31.029, P < 0.001). There were no statistical significances in crude prevalences of bronchiectasis among cities (χ² = 10.572, P = 0.103), while there was a significant difference among cities after adjustment with confounders (Wald value = 22.116, P = 0.001), by using logistic regression analysis. Logistic regression analysis showed, bronchiectasis was significantly associated with elder ( ≥ 70 years vs 40-49 years; OR = 4.11, 95% CI 2.29-7.36), the family history of respiratory diseases (having two subjects with respiratory diseases in family vs no suffered relatives; OR = 2.04, 95% CI 1.06-3.94), respiratory infection during childhood (suffering two kinds of respiratory diseases vs never; OR = 4.89, 95% CI 2.03-11.81), exposure to coal (OR = 2.30, 95% CI 1.17-4.52), chronic pharyngitis (OR = 3.96, 95% CI 1.38-11.40) and pulmonary tuberculosis (OR = 3.07, 95% CI 1.89-4.98), heart diseases (OR = 1.64, 95% CI 1.11-2.42) and lung cancer(OR = 18.61, 95% CI 7.67-45.18). CONCLUSION: The prevalence of bronchiectasis in population aged 40 years old and above in urban area in China is high and associated with multiple factors such as age, family history of respiratory diseases, respiratory infection during childhood, exposure to coal, chronic pharyngitis, pulmonary tuberculosis, heart diseases, lung cancer and so on.

[Effects of shadow boxing training on exercise endurance and quality of life of patients with chronic obstructive pulmonary disease].

OBJECTIVE: To evaluate the effects of shadow boxing training on the exercise endurance and quality of life of Chinese patients with COPD (chronic obstructive pulmonary disease). METHODS: From May 2010 to March 2011, a total of 70 COPD patients in stable phases were recruited from Liwan, Yuexiu and Haizhu districts of Guangzhou. There were 35 patients in the shadow boxing exercise group and 35 patients in the control group. And they were matched by gender and age. The patients in the shadow boxing group exercised for 3 months while those in the control group received the conventional out-hospital management only. Their demographic, medical history, smoking status, medicinal use, spirometric data, clinical COPD questionnaire (CCQ) scores, 6-minute walking distance and Borg scores were collected before and after trial. RESULTS: A total of 63 COPD patients (33 in shadow boxing group vs. 30 in control group) completed the study. There was an average dropout rate of 5.7% (2/35) in shadow boxing group and 14.3% (5/35) in control group. No differences existed between two groups in age (67 ± 8 vs 69 ± 9 yr), male proportion (84.8% vs 86.7%), body mass index (22.8 ± 2.6 vs 22.7 ± 3.0), usage proportion of medicine (42.4% vs 33.3%), duration of disease (4.0 ± 7.5 vs 5.5 ± 7.3), percentage of smokers (78.8% vs 80.0%), 6-minute walking distance (447 ± 94 vs 414 ± 100), CCQ total score (15.0 ± 9.4 vs 14.1 ± 8.8), CCQ symptom score (9.2 ± 5.6 vs 8.3 ± 5.0) and activity score (5.8 ± 4.5 vs 5.8 ± 4.4) at baseline (all P > 0.05). At the end of study, the 6-minute walking distance of patients had statistical differences between two groups (P < 0.01). The shadow boxing group increased by (51 ± 55) m while the control dropped by (19 ± 58) m. The total score, symptom score and activity score of clinical COPD questionnaire had statistical differences between two groups. They decreased significantly in the shadow boxing group as compared with the baseline data while there was no significant change in the control group. No statistical differences existed between two groups in the changes of forced vital capacity (FVC), forced expiratory volume in one second (FEV(1)), FEV(1)% pred, Borg score and dyspnea scales. CONCLUSION: Capable of improving the exercise endurance and life quality of COPD patients, shadow boxing exercise may become one of effective rehabilitation programs for COPD patients in stable phases in communities.

[Health risk assessment of atmospheric volatile organic compounds in urban-rural juncture belt area].

A method for determining volatile organic compounds (VOCs) by cryogenic dynamic adsorption in solid adsorbent tubes, subsequent thermal desorption with cryofocusing in a cold trap and analysis by gas chromatography and mass spectrometry was adapted. An internationally recognized four-step evaluation model of health risk assessment (HRA) was adapted to preliminarily assess the health risks caused by volatile organic compounds (VOCs) in urban-rural juncture belt area in Beijing. Results of HRA indicated that non-carcinogenic risk indexes of VOCs are below 1 and non-carcinogenic risk indexes of aromatic substances range from 10(-4)-10(-5), halohydrocarbons in the 10(-4)-10(-1). Volatile pollutants would not cause non-carcinogenic health hazard to exposed population. However, the cancer risk index exposed to carcinogenic benzene was 2.21 x 10(-5), which is higher than that suggested value of USEPA (1x10(-6)) and may cause potential harm to human health. The greatest health risk is in winter, followed by autumn, summer minimum.

[Pollution and source of atmospheric volatile organic compounds in urban-rural juncture belt area in Beijing].

A method for determining volatile organic compounds (VOCs) by cryogenic dynamic adsorption in solid adsorbent tubes, subsequent thermal desorption with cryofocusing in a cold trap and analysis by gas chromatography and mass spectrometry was adapted. Volatile organic content levels, spatial and temporal distribution and sources were studied. Results indicated that 265 species were detected in atmospheric environment of this area, including alkanes, alkenes, aromatics, halohydrocarbons and oxygenated compounds. The average concentration of VOCs is 431.7 microg x m(-3), followed by aromatics 248.1 microg x m(-3), alkanes 130.5 microg x m(-3) alkenes 11.7 microg x m(-3), halohydrocarbons 22.4 microg x m(-3), oxygenated compounds 18.6 microg x m(-3), respectively. Benzene, toluene, ethylbenzene, xylene and so on have a comparatively high content. Aromatics and alkanes are the most abundant VOCs; Organic pollutants generally occurred at a relatively high level in the morning and evening traffic rush hours. VOCs varied with seasons: winter maximum, followed by autumn, summer minimum. Source analysis showed that atmospheric VOCs mainly come from vehicular exhaust, gasoline evaporation, use of adhesive and solvent and vegetation emission. They accounted for 53.4%, 20.1%, 11.0% and 5.93%, respectively.

[Clinical characteristics and prognostic factors of pulmonary embolism in different age groups].

OBJECTIVE: To explore the clinical characteristics of pulmonary embolism (PE) in different age-groups and to analyze prognostic factors of PE. METHODS: Data of 209 PE patients diagnosed in our hospital from 2004 to 2009 were reviewed retrospectively. RESULTS: Of the 209 patients with PE, 95 subjects (45.5%) were over the age of 65, and 114 were ≤ 65 years. The third leading comorbidity were activity limitation that were banding in bed, chronic obstructive pulmonary disease, neoplasm and hypertension, accounting for 42.1%, 24.4% and 21.5%, respectively. The typical clinical presentations included dyspnea(83.7%), cough (74.2%), chest pain (29.2%), haemoptysis (15.3%) and syncope (3.8%). In 186(92.1%) patients, D-dimer was above the normal level, 37.8% (79) and 54.0% (81/150) subjects were found having got a venous thrombosis in lower extremity and pulmonary hypertension, respectively by using ultrasonic visualization. 16.7% (35) and 80.9% (169) had received thrombolytic and anticoagulant therapy, respectively. The death rate of PE was 6.7%. A difference in clinical characteristics was observed between younger and older patients. The later had more comorbidity such as COPD, neoplasm and hypertension, the older patients had fewer complaints of chest pain, haemoptysis, fever, hypotension and typical electrocardiogram (ECG), but had more cough with sputum, pulmonary rales and lower extremity edema, in comparison to the younger patients. The older PE patients were less likely to suffer from large thrombosis and pulmonary infarction, and to received thrombolytic therapy. Multivariate logistic regression showed that PaO(2) < 60 mm Hg (1 mm Hg = 0.133 kPa), having pulmonary rales, having abnormal neutrophilic granulocyte counts, not receiving thrombolysis and anticoagulant therapy, suffering from emergency rescue, having comorbidities with tumor and pneumonia were important prognostic factors. CONCLUSION: The clinical features of PE were various and non-specific. More attention should be paid to PE patients, in particular to older patients who usually had more comorbidities and non-specific clinical manifestations.

Asymptomatic patients of chronic obstructive pulmonary disease in China.

BACKGROUND: Chronic obstructive pulmonary disease (COPD) has a variable natural history and not all individuals follow the same course. This study aimed to identify the prevalence and characteristics of asymptomatic COPD patients from a population-based survey in China. METHODS: A multistage cluster sampling strategy was used in a population from seven different provinces/cities. All residents (over 40 years old) were interviewed with a standardized questionnaire and spirometry. Post-bronchodilator forced expiratory volume in 1 second (FEV(1))/forced vital capacity (FVC) of less than 70% was defined as the diagnostic criterion of COPD. All COPD patients screened were divided into symptomatic group and asymptomatic group according to the presence or absence of chronic respiratory symptoms. Socio-demographic, personal and exposure variables were collected and analyzed. RESULTS: Among the 1668 patients who were diagnosed with COPD from the 25 627 sampling subjects, 589 (35.3%) were asymptomatic. The age, sex, body mass index (BMI), rural and urban distributions, smoking habit and education levels were similar in the two groups. A total of 64.7% of the asymptomatic patients had no comorbidities. Cardiovascular diseases and lung cancer were more common among symptomatic COPD patients than asymptomatic group. Asymptomatic COPD group were less likely to present with poor ventilation in the kitchen, a family history of respiratory disease and recurrent childhood cough. Asymptomatic COPD patients had significantly higher FEV(1) (73.1% vs. 61.0%), FVC (91.9% vs. 82.0%), and a higher ratio of FEV(1)/FVC (62.9% vs. 58.7%) (all P < 0.001) than symptomatic group. More asymptomatic patients were underdiagnosed (91.9% vs. 54.3%, P < 0.001) than symptomatic patients. CONCLUSIONS: This large population-based survey confirmed a high prevalence of asymptomatic COPD patients in China. More use of spirometry screening test may be important to the early detection of COPD.

[Current status of prevention and management of chronic obstructive pulmonary disease in rural area in China].

OBJECTIVE: To investigate the current status of prevalence, prevention and management of chronic obstructive pulmonary disease (COPD) in rural area in China. METHODS: A cross-sectional survey of COPD was conducted in Beijing city, Shanghai city, Guangdong province, Liaoning province, Tianjin city, Chongqing province and Shanxi province. A population-based cluster sample was randomly selected from each rural area. In the selected community, all residents at least 40 years old were recruited, and interviewed with a modified standardized questionnaire from the international burden of obstructive lung diseases (BOLD) study. All participants were tested with spirometry. Those with airflow limitation were performed on post-bronchodilator spirometry. The post-bronchodilator a ratio of forced expiratory volume in one second to forced vital capacity (FEV1/FVC) less than 70% was defined as the diagnostic criteria of COPD. RESULTS: (1) Data of 9434 participants was valid for analysis, with a valid response rate of 83.6%; the prevalence of COPD in rural was 8.8% (830/9434), 12.8% in male and 5.4% in female. (2) The percentage of smoking and the exposure to biomass smoke in rural was 43.0% (4059/9434) and 83.1% (7835/9434) respectively; cigarettes cessation rate was 17.5%; only 12.4% (502/4059) of smokers had received advice to quit smoking. (3) Among COPD patients, only 30.0% (249/830) had ever been diagnosed as COPD, bronchitis, emphysema, or asthma, 2.4% (20/830) had ever received spirometric tests, and 74.5% were current smokers; only 7.9% (50/634) COPD patients in stage two or over had received regular drug treatment. CONCLUSION: There was high prevalence and poor prevention and management for COPD in rural areas. Therefore, an enforced prevention and management for COPD are urgent.

[The quality of life of patients with chronic obstructive pulmonary disease and correlated factors].

OBJECTIVE: To evaluate the quality of life (QOL) of patients with chronic obstructive pulmonary disease (COPD) and correlated factors. METHODS: Data of 20 245 patients with COPD were collected from the cross-sectional survey of COPD, which was conducted between 2002 and 2004 in urban and rural areas of Beijing, Shanghai, Guangdong, Liaoning, Tianjin, Chongqing and Shanxi for residents aged over 40 years old. The recruited populations were interviewed with questionnaire and tested for spirometry. The quality of life was assessed with 12-item short-form health survey questionnaire (SF-12). Those with less than 70% of post-bronchodilator FEV(1)/FVC were identified as having COPD. The differences between groups in SF-12 scores converted by rank were compared using general linear model. Stepwise multiple linear regressions were conducted to study the main determinants of QOL. RESULTS: Compared to subjects without COPD, those with COPD had impaired QOL (56 +/- 7 vs. 57 +/- 6 in mental component scores, F = 4.442, P < 0.05; 46 +/- 9 vs. 50 +/- 6 in physical component scores, F = 453.960, P < 0.05). Among COPD patients, the mental component score was associated with scores of dyspnea, BMI, comorbidities, sex and living areas, while the physical component score was associated with scores of dyspnea, severity of COPD, comorbidities, exposure to dusts/gases/fumes, sex, age, educational level and previous diagnosis of respiratory diseases (all P < 0.05). CONCLUSIONS: The QOL in patients with COPD was impaired and associated with scores of dyspnea, severity of COPD, comorbidities and BMI. Improvement of dyspnea, nutritional support, prevention of comorbidities and keeping away from risk factors may improve the QOL in COPD patients.

[A study on the correlation of body mass index with chronic obstructive pulmonary disease and quality of life].

OBJECTIVE: To investigate the correlation between body mass index (BMI) and chronic obstructive pulmonary disease (COPD), based on a cross-sectional COPD survey conducted in Beijing, Shanghai, Guangdong, Liaoning, Tianjin, Chongqing and Shaanxi of China between 2002-2004. METHODS: A multi-stage stratification cluster sampling strategy was used in this cross-sectional survey, and 20,245 subjects (8705 males and 11,540 females) aged 40 years or older were recruited, interviewed with a questionnaire, measured for height and weight, and tested with spirometry. 1668 subjects with post-bronchodilator FEV1/FVC less than 70% were identified as having COPD after other known causes of airflow limitation were excluded. Analysis on relationship between COPD and BMI was performed in 1668 COPD and 18 577 non-COPD subjects. RESULTS: Compared with non-COPD subjects, BMI was significantly lower in COPD patients [(22.7+/-3.5) vs (24.1+/-3.4) kg/m2, F=158.31, P<0.01]; BMI was also significantly lower in smokers than in non-smokers [(23.6+/-3.4) vs (24.2+/-3.5) kg/m2, F=49.10, P<0.01]. And an addictive interaction to BMI between COPD and smoking was observed (F=6.03, P<0.05). BMI decreased with the increase of the stage of COPD (F=45.6, P<0.01), with a negative relationship (r=-0.08, P<0.01). Lower BMI was significantly associated with increased risk of COPD (chi2=102.68, P<0.01). Compared with subjects with normal BMI (BMI=24.0-27.9 kg/m2), those with lower BMI (BMI<18.5 kg/m2) were more likely to have COPD [adjusted OR=2.12 (95% CI 1.73-2.59)], while those with higher BMI (BMI=24.0-27.9 kg/m2) and obesity (BMI>or=28.0 kg/m2) were less likely to have COPD [adjusted OR=0.67 (95% CI 0.59-0.76); and 0.60 [(95% CI 0.49-0.73), respectively]. Moreover, there was an interaction to COPD between smoking and BMI (chi2=4.73, P<0.05). Compared with COPD patients with normal BMI, the quality of life in those with lower BMI was impaired (55+/-8 vs 57+/-6 in mental scores of SF-12, F=2.96, P<0.05; 42+/-10 vs 46+/-9 in physical scores of SF-12, F=4.21, P<0.01), and their dyspnea scores were higher (1.4+/-1.5 vs 1.1+/-1.3, chi2=14.32, P<0.01). CONCLUSION: Lower BMI was strongly associated with COPD, possibly as a risk factor for COPD independent of smoking, and a potential predictor for COPD severity.

[Theophylline in the treatment of chronic obstructive pulmonary disease: a randomized, double-blind, placebo-controlled study].

OBJECTIVE: To observe the benefits and safety of low-dose, slow-release oral theophylline for long-term treatment of stable chronic obstructive pulmonary disease (COPD). METHODS: This was a randomized, parallel-group, double-blind, placebo-controlled trial. Slow-release theophylline (200 mg/d) twice daily or placebo (matching theophylline) was randomly given to 110 patients with stable COPD in the rural area of Shaoguan, Guangdong Province, for one year. Efficacy measures were spirometry and exacerbations, quality of life, dyspnea scores, satisfaction with treatments and adverse effects. Comparison of benefits was performed using superiority test. RESULTS: Of 110 patients, 85 (42 subjects in theophylline group and 43 subjects in placebo group) completed the study. An analysis for intention-to-treat (ITT) individuals showed that individuals with the treatment of theophylline experienced statistically fewer numbers [(0.8 +/- 1.2) times/year, (1.7 +/- 2.6) times/year, Z = -1.674, P = 0.047] and days of exacerbations [(4.6 +/- 7.9) d, (12.5 +/- 22.8) d, Z = -1.699, P = 0.045] in comparison to subjects receiving placebo, that patients receiving theophylline were less likely than the placebo group to experience moderate exacerbations [(0.4 +/- 1.0) times/year, (1.0 +/- 1.8) times/year, Z = -2.136, P = 0.017], and that more individuals satisfied with treatments in the theophylline group than the placebo group (n = 16, 3, Z = -2.198, P = 0.014), and that statistically greater improvement in pre-bronchodilators FEV(1) [(0.006 +/- 0.180) L, (-0.053 +/- 0.169) L, t = 1.789, P = 0.038] were found in the theophylline group in comparison to the placebo group. The similar results were observed in an analysis for per-protocol (PP) subjects. Statistical improvement on quality of life was observed in the PP subjects of theophylline group than in placebo group (-28 +/- 20, -20 +/- 23, F = 2.893, P = 0.047). Time to the first exacerbation in patients receiving theophylline was also delayed in comparison to placebo (365 d, 276 d, chi(2) = 3.880, P = 0.049). But no statistical difference was found between the two groups in post-bronchodilators FEV(1) in both ITT and PP subjects (t = -0.012, P = 0.495 and t = 0.040, P = 0.484 respectively). Drug-related adverse events (8.8%) such as insomnia, palpitation, stomach discomforts or stomachache, and headache were observed in the theophylline group. CONCLUSION: Slow-released oral theophylline (200 mg/d) may be beneficial and safe in long-term treatment of stable COPD in rural area.

[A study on the methodology regarding the prevalence survey of chronic obstructive pulmonary disease in China].

OBJECTIVE: To explore the methodology on prevalence study of chronic obstructive pulmonary disease (COPD) in line with the world, to obtain accurate epidemic data of COPD in China. METHODS: A national multi-center cross-sectional survey on prevalence, risk factors and burden of COPD was conducted in China. In each area, a population-based cluster sample of approximately 1450 individuals aged 40 years or older was interviewed, using standardized questionnaires that were revised on the methodology of burden of lung diseases (BOLD) study and according under the context of China. All participants were submitted to pre-bronchodilator spirometry. Those with airflow limitation received post-bronchodilator spirometry, physical examination, X-rays of chest and EKG (electrocardiogram) tests. The post-bronchodialators FEV1/FVC < 70% was identified as having COPD. RESULTS: Investigation has been completed with the same standardized procedures by all sites, up to the requirement of quality control. Over 85.0% of the spirometry tests and 95.0% of questionnaires had met the criteria of quality control in each area. Overall, 95.2% of the data was valid with acceptable spirometry and questionaire, and the valid response rate was 79.0%. CONCLUSION: The protocol was in line with the international standards, by which the prevalence of COPD in China was of adequate quality and valid.

[The risk factors for chronic obstructive pulmonary disease in females in Chinese rural areas].

OBJECTIVE: To explore the risk factors for chronic obstructive pulmonary disease (COPD) in females in Chinese rural areas. METHODS: Based on a national multi-center, population-based and cross-sectional survey on prevalence of COPD in seven provinces/cities of China, an analysis on the risk factors for the rural females was conducted in six areas, e.g. Beijing, Shanghai, Guangdong, Liaoning, Tianjin and Shanxi. In the national survey, for each area, one rural and one urban cluster samples were randomly selected using a multi-stage strategy. Residents who were 40 years old or older were interviewed with questionnaires and tested with spirometry. The post-bronchodilators forced expired volume in one second to forced vital capacity ratio (FEV(1)/FVC) x 100% < 70% was used as diagnostic criteria of COPD. RESULTS: The average prevalence of COPD in females in the six Chinese rural areas was 5.4%. The prevalence varied with risk factor exposure among different areas, and the prevalence in Guangdong province was the highest among all areas. Logistic regression model was conducted, and statistical association of COPD was found with a family history of respiratory diseases (OR = 2.46, 95% CI = 1.86 - 3.26), frequent coughing during childhood (frequent coughing vs never coughing: OR = 3.93, 95% CI = 2.02 - 7.63), lower body mass index (lower body mass index vs normal body mass index: OR = 2.20, 95% CI = 1.47 - 3.29), age (70 years or older vs 40 - 49 years: OR = 8.98, 95% CI = 5.90 - 13.67), smoking (OR = 1.68, 95% CI = 1.20 - 2.35), exposure to occupational dusts (OR = 1.45, 95% CI = 1.07 - 1.96), worse ventilation in kitchen room (OR = 1.47, 95% CI = 1.06 - 2.03) and lower educational level (OR = 2.19, 95% CI = 1.38 - 3.46). CONCLUSION: The prevalence of COPD in females in rural areas was associated with multiple factors and prevention of COPD for Chinese women in rural areas is warranted.

[Epidemiologic analysis of COPD in Guangdong province].

OBJECTIVE: To survey the prevalence of chronic obstructive pulmonary disease (COPD) in urban and rural areas in Guangdong Province and relevant risk factors. METHODS: Using the same protocol including Burden of Obstructive Lung Disease (BOLD) questionnaire, a questionnaire survey was conducted among 3449 respondents, 1370 males and 1916 females, aged over 40 with an average age of 56.8, by random disproportional cluster sampling in Liwang District of Guangzhou City and Yunyan Town, Lechang City, northern Guangdong Province. Spirometry was performed in all subjects. Lung function indices were regarded as gold criteria of diagnosis of COPD. RESULTS: There were 3286 cases with full data and good quality spirometry test, 1370 males and 1916 females, aged 56.8. The total prevalence of COPD was 9.4%. The prevalence of COPD in the males was 15.9%, significantly higher than that in the females (4.8%, P < 0.01). The prevalence in the rural area was 12.0%, significantly higher than that in the urban area (7.4%, chi(2) = 20.3, P < 0.01). 67.7% of the patients with COPD presented symptoms such as cough, expectoration and/or dyspnoea. 58.7% of the COPD patients (78.9% of the male patients and 10.9% of the female patients) smoked. The odd ratio (OR) for COPD in the smokers was 2.59 (95% CI 1.87 - 3.59). Only 15.1% of the smokers (17.9% of the male smokers and 4.1% of the female smokers) developed COPD. No significant relationship was found between pack years of cigarette smoking and COPD prevalence. The risk of COPD was increased when biomass fuels were used in house cooking (OR = 1.54 95% CI 1.08 - 2.20). Furthermore, the combination of biomass fuels and cigarette smoking further increased the risk with the OR of 4.41 (95% CI 3.22 - 6.04), indicating a synergetic impact of smoking and biomass burning on the prevalence of COPD. The Prevalence of doctor-diagnosed COPD based on the clinical manifestation was significant lower than the actual prevalence (only 31.0%). CONCLUSIONS: COPD is a very common disease in Guangdong. The prevalence of COPD is higher in the rural area than in the urban area, which may be attributed to the synergic effect of smoking and biomass burning. Lung function test is of great importance in COPD diagnosis, especially in the earlier stage of COPD and those asymptomatic COPD patients.

[Study on the prevalence rate of chronic obstructive pulmonary disease in northern part of Guangdong province].

OBJECTIVE: To investigate the prevalence of chronic obstructive pulmonary disease (COPD) and its risk factors in population over 40 years old in northern part of Guangdong province. METHODS: Using uniform scheme, procedures and questionnaire, a cluster-randomized-sampling survey for the population aged over 40 years in a rural area of Shaoguan in the northern part of Guangdong province was performed. Spirometry was performed for every participant, followed by a bronchodilatation test when bronchial obstruction was present. RESULTS: There were 1468 cases with complete data from 1498 people aged >or= 40 years including 640 males, 828 females with an average age of 54.3 years old. The total prevalence of COPD was 12.0%. The prevalence of COPD in males was significantly higher than that in females (18.3% vs. 7.1%, P < 0.01). Only 80.7% of the patients with COPD presented one or more symptoms as cough, phlegm, or dyspnoea. Underdiagnosis of COPD would be quite serious. Only 26.1% of the cases was previously diagnosed to have chronic bronchitis, emphysema, or COPD. Smoking was an important risk factor to COPD and 78.4% of the patients with COPD were smokers. However, relation of biomass and COPD called for further investigation. CONCLUSION: Prevalence of COPD was much higher than expected in the northern part of Guangdong while smoking was an most important risk factor of COPD. Lung function test seemed to be of great importance to COPD diagnosis, especially in the earlier period of COPD.