Bronchial reactivity to cigarette smoke; relation to lung function, respiratory symptoms, serum-immunoglobulin E and blood eosinophil and leukocyte counts

STUDY OBJECTIVES: The aim of the study was to investigate the relationship between the immediate bronchial response to inhaled cigarette smoke [cigarette smoke bronchial reactivity (CBR)] and lung function, respiratory symptoms and markers of allergy and inflammation. DESIGN, PARTICIPANTS AND MEASUREMENTS: This cross-sectional study included 98 smokers. Their lung function and reversibility to inhaled terbutaline was measured. Their clinical history was obtained, an allergological examination was done, and bronchial reactivity to methacholine and inhaled cigarette smoke was measured. Questionnaires about respiratory symptoms, smoking history and drug usage were completed and a blood sample was obtained. Participants were divided into three groups: with asthma, chronic bronchitis and persons without asthma or chronic bronchitis (the respiratory healthy). RESULTS: Forced expiratory volume in 1sec (FEV1) residuals were independently related to the % fall in FEV1 after 12 cigarette smoke inhalations (DFEV%) in all participants (P<001), in asthmatic smokers (P<0.01) and in smokers with chronic bronchitis (P<0.05). In smokers with asthma and chronic bronchitis FEV1 residuals explained 51% and 13% of the variation in DFEV%, respectively, but only 8% (P<0.05) and 1% (N.S.) of the variation in the methacholine bronchial reactivity. In the total population the presence of wheeze (P<0.01), attacks of breathlessness (P<0.05) and daily expectoration (P<0.001) were related to higher DFEV% readings. Serum immunonoglobulin (ES-IgE) was independently related to DFEV% in all participants (P<0.01), in smokers with chronic bronchitis (P<0.01) and in the respiratory healthy (0.05相似文献   

The proportional Venn diagram of obstructive lung disease: two approximations from the United States and the United Kingdom

STUDY OBJECTIVES: The nonproportional Venn diagram of obstructive lung disease (OLD) produced for the 1995 American Thoracic Society guidelines has not been quantified. We aim to quantify the proportion of the general population with OLD and the intersections of physician-diagnosed asthma, chronic bronchitis, and emphysema in the United States and the United Kingdom, and to examine the relationship to obstructive spirometry. DESIGN AND PARTICIPANTS: We analyzed data from the US National Health and Nutrition Examination (NHANES) III survey (1988 to 1994) and the UK General Practice Research Database for the year 1998. RESULTS: The areas of intersection among the three OLD conditions produced seven mutually exclusive disease groups. The asthma-only group was the largest proportion of OLD patients, accounting for 50.3% and 79.4% of all OLD patients in the United States and the United Kingdom, respectively, and decreased with increasing age. Overall, 17% and 19% of OLD patients in the United States and in the United Kingdom, respectively, reported more than one OLD condition, and this percentage increased with age. According to the spirometry data from NHANES III, only 37.4% of emphysema-only patients had objective airflow obstruction. The prevalence of airflow obstruction was significantly higher among participants with combinations of emphysema and chronic bronchitis (57.7%), with emphysema and asthma (51.9%), and with all three OLD diseases concomitantly (52.0%). CONCLUSION: Concomitant diagnosis of asthma, chronic bronchitis, or emphysema is common among OLD patients from the general population, particularly in adults aged > or = 50 years.     

Prevalence and Risk Factors for Chronic Obstructive Pulmonary Disease According to Symptoms and Spirometry

The burden of COPD is quite high and its prevalence is increasing. Few data are available from Latin America. There is no consensus on what criteria should be the gold standard for the definition of this disease. A population‐based study was carried out in a southern Brazilian city, including adults aged 40–69 years. The aim was to measure the prevalence of COPD according to several criteria. From the 1,046 subjects chosen from a multiple‐stage sampling protocol, a sub‐sample of 234 subjects was systematically selected to undergo spirometry. Percentages of COPD according to different criteria were: chronic bronchitis by questionnaire (7.8%); GOLD stage 0 (7.3%); fixed ratio (15.2%); GOLD stage II (9.9%); ERS (27.7%). The relationship among the three lung functional measurements showed that around 70% of all subjects had negative results with all three criteria, and around 10% were positive according to all three. Utilization of symptom‐based or spirometry definitions of COPD provide different prevalence estimates. Use of different spirometric criteria also resulted in different percentages of COPD. According to spirometry, COPD was higher among men, elderly, those with low education and ex‐smokers. On the other hand, current smokers were more likely to present symptoms of chronic bronchitis. The fixed ratio criterion is recommended when population‐specific reference curves are not available, while the GOLD definition is recommended to evaluate severity of COPD.     

Docosahexaenoic acid and smoking-related chronic obstructive pulmonary disease. The Atherosclerosis Risk in Communities Study Investigators.

If the inflammatory response to inhalation of cigarette smoke causes chronic obstructive pulmonary disease (COPD), suppression of that natural response might be beneficial. We hypothesized that a smoker's risk of developing COPD is inversely related to physiologic levels of two fatty acids that have antiinflammatory properties: eicosapentaenoic acid (EPA, C20:5) and docosahexaenoic acid (DHA, C22:6). The proportion of each fatty acid in plasma lipids was measured in 2,349 current or former smokers. COPD was identified and defined by clinical symptoms and/or spirometry. After adjustment for smoking exposure and other possible confounders, the prevalence odds of COPD were inversely related to the DHA (but not to the EPA) content of plasma lipid components in most of the models. For example, as compared with the first quartile of the DHA distribution, the prevalence odds ratios (ORs) for chronic bronchitis were 0.98, 0.88, and 0.69 for the second, third, and fourth quartiles, respectively (p for linear trend = 0.09). The corresponding ORs for COPD as defined spirometrically, were 0.65, 0.51, and 0.48 (p < 0. 001). Among 543 current heavy smokers, adjusted mean values of FEV1 (lowest to highest DHA quartile) were 2,706, 2,785, 2,801, and 2,854 ml. DHA may have a role in preventing or treating COPD and other chronic inflammatory conditions of the lung. Pilot testing of that hypothesis in experimental models seems warranted.     

Prevalence and risk factors for chronic obstructive pulmonary disease according to symptoms and spirometry

The burden of COPD is quite high and its prevalence is increasing. Few data are available from Latin America. There is no consensus on what criteria should be the gold standard for the definition of this disease. A population-based study was carried out in a southern Brazilian city, including adults aged 40-69 years. The aim was to measure the prevalence of COPD according to several criteria. From the 1,046 subjects chosen from a multiple-stage sampling protocol, a sub-sample of 234 subjects was systematically selected to undergo spirometry. Percentages of COPD according to different criteria were: chronic bronchitis by questionnaire (7.8%); GOLD stage 0 (7.3%); fixed ratio (15.2%); GOLD stage II (9.9%); ERS (27.7%). The relationship among the three lung functional measurements showed that around 70% of all subjects had negative results with all three criteria, and around 10% were positive according to all three. Utilization of symptom-based or spirometry definitions of COPD provide different prevalence estimates. Use of different spirometric criteria also resulted in different percentages of COPD. According to spirometry, COPD was higher among men, elderly, those with low education and ex-smokers. On the other hand, current smokers were more likely to present symptoms of chronic bronchitis. The fixed ratio criterion is recommended when population-specific reference curves are not available, while the GOLD definition is recommended to evaluate severity of COPD.     

Thirty-year cumulative incidence of chronic bronchitis and COPD in relation to 30-year pulmonary function and 40-year mortality: a follow-up in middle-aged rural men

PURPOSE: To describe the 30-year cumulative incidence of chronic bronchitis and COPD in relation to smoking habits. The effect of chronic bronchitis on pulmonary function and mortality was also examined. METHODS: Middle-aged men belonging to two rural Finnish cohorts of the Seven Countries Study (n = 1,711 in 1959) were followed up for up to 40 years until 2000. Standard questionnaires were used to measure chronic bronchitis, and repeated spirometry was used to evaluate pulmonary function during the 30 years. Forty-year mortality data were examined. RESULTS: The cumulative incidence of chronic bronchitis and COPD was 42% and 32%, respectively, in continuous smokers, compared to 26% and 14% in ex-smokers and 22% and 12% in never-smokers. During the follow-up, subjects with chronic bronchitis had on average 252 mL (95% confidence interval, 211 to 293 mL) lower forced expiratory volume than those without it. The decrease in forced expiratory volume attributable to chronic bronchitis was most pronounced in those with persistent symptoms and in smokers. In subjects with chronic bronchitis, all-cause mortality was increased by a hazard ratio of 1.30 (95% confidence interval, 1.02 to 1.65). Smokers with chronic bronchitis who decreased their daily cigarette consumption increased their median life span by 2.4 years. CONCLUSIONS: The lifetime risk of chronic bronchitis among smokers is approximately two in five, and almost one half of smokers who have chronic bronchitis also acquire COPD. Chronic bronchitis is related to earlier death, also in never-smokers, probably partly through a rapid decline in pulmonary function.     

Relationship between chronic nasal and respiratory symptoms in patients with COPD

The relationship between the upper and lower airways in chronic obstructive pulmonary disease (COPD) is unknown. We examined the prevalence of chronic nasal symptoms and the correlation with lower respiratory symptoms and parameters of severity of COPD such as exacerbation frequency and spirometry. 61 COPD patients from the East London COPD cohort were studied. [Mean (SD) age 70 (6.96) years, FEV1 0.98 (0.38) l, FVC 2.45 (0.72) l, FEV1%Pred 37.0 (12.3), and 47.6 (31.8) smoking pack years, 14 current smokers, 36 males]. COPD patients had a high prevalence of nasal symptoms (75%), more than half reporting nasal discharge (52.5%) and sneezing (45.9%). Associations were found between nasal score and daily sputum production (P = 0.005) and post-nasal drip and sputum production (P = 0.046) with a trend to increased nasal symptoms in frequent exacerbators compared to infrequent exacerbators. No significant relationship was found between nasal symptoms and FEV1 or any other lower respiratory airway symptom. Associations between nasal and respiratory symptoms were found suggesting that there is a relationship between the upper and lower airway in COPD.     

Prevalence of chronic obstructive pulmonary disease in China: a large, population-based survey

RATIONALE: The prevalence of chronic obstructive pulmonary disease (COPD) in China is largely unknown. OBJECTIVES: To obtain the COPD prevalence in China through a large-population, spirometry-based, cross-sectional survey of COPD. METHODS: Urban and rural population-based cluster samples were randomly selected from seven provinces/cities. All residents 40 years of age or older in the selected clusters were interviewed with a standardized questionnaire revised from the international BOLD (Burden of Obstructive Lung Diseases) study. Spirometry was performed on all eligible participants. Patients with airflow limitation (FEV(1)/FVC < 0.70) were further examined by post-bronchodilator spirometry, chest radiograph, and electrocardiogram. Post-bronchodilator FEV(1)/FVC of less than 70% was defined as the diagnostic criterion of COPD. MEASUREMENTS AND MAIN RESULTS: Among 25,627 sampling subjects, 20,245 participants completed the questionnaire and spirometry (response rate, 79.0%). The overall prevalence of COPD was 8.2% (men, 12.4%; women, 5.1%). The prevalence of COPD was significantly higher in rural residents, elderly patients, smokers, in those with lower body mass index, less education, and poor ventilation in the kitchen, in those who were exposed to occupational dusts or biomass fuels, and in those with pulmonary problems in childhood and family history of pulmonary diseases. Among the patients who had COPD, 35.3% were asymptomatic; only 35.1% reported lifetime diagnosis of bronchitis, emphysema, or other COPD; and only 6.5% have been tested with spirometry. CONCLUSIONS: COPD is prevalent in individuals 40 years of age or older in China.     

Respiratory symptoms and occupational bronchitis in chromite ore miners, Sudan

Prevalence of respiratory symptoms and chronic bronchitis was determined in a group of 122 subjects (77 exposed miners, 18 partially exposed, 27 controls) working at chromite ore mines in Sudan. The mean ages (+/- s.d.) of the three groups were 36.4 (+/- 7.8), 35.2 (+/- 6.8) and 34.6 (+/- 7.5) years respectively. Methods included a respiratory symptoms questionnaire based on the British Medical Research Council (MRC 1976) questionnaire on respiratory symptoms, determination of FEV1, FVC and FEV1/FVC%. The majority (66%) of the exposed subjects were non-smokers (NS) and 20 (77%) of the 'ever-smokers' (current and ex-smokers) were smokers of less than 15 cigarettes day-1. Respiratory symptoms (cough, phlegm, dyspnoea) were more frequent among the miners and so was chronic bronchitis. The prevalence of the latter was 26% among the miners compared to 11% and 7% among the partially exposed and the controls respectively. These differences could not be accounted for by cigarette smoking. Sixty-five per cent of the miners diagnosed as having asthma, chronic bronchitis or both were non-smokers. Although the values for the FEV1/FVC% remained normal or near the lower limits of the normal range, the mean value was significantly lower among the miners. It was concluded that the mine dust was the prime cause of the respiratory symptoms and chronic bronchitis among the miners.     

The use of microspirometry in detecting lowered FEV1 values in current or former cigarette smokers

AIMS: COPD is an underdiagnosed disease. This study was undertaken to assess the value of microspirometry in detecting reduced FEV1 values in cigarette smokers, i.e., subjects at high risk for COPD. METHODS: A total of 611 smokers or ex-smokers with a smoking history >20 years and no previously-diagnosed lung disease were recruited (389 male, age 27-83 years, mean age 56 years, mean smoking history 35 pack years, 19% ex-smokers). RESULTS: An FEV1 < 80% predicted on microspirometry was found in 44.6% of cases. The mean FEV1 was 2.8 litres (80.6% predicted, range 26-121%). This correlated well with values obtained from full spirometry (R=0.965, p<0.0001). Detailed questionnaire responses revealed that almost half of the subjects (48.2%) reported chronic cough and sputum production and 39.8% reported breathlessness during exercise. CONCLUSIONS: Microspirometry finds a considerable number of smokers or ex-smokers with reduced FEV1 values. Microspirometry is quick to perform. All smokers with reduced microspirometry FEV1 values would benefit from smoking cessation, and all patients with reduced FEV1 values need to be considered for full spirometry to confirm if they actually have COPD.     

Occupation, chronic bronchitis, and lung function in young adults. An international study

We studied the relationship between occupational exposures, chronic bronchitis, and lung function in a general population survey in 14 industrialized countries, including 13,253 men and women aged 20 to 44 yr. We studied associations between occupational group, occupational exposures, bronchitis symptoms (cough and phlegm production for at least 3 mo each year), FEV(1), and nonspecific bronchial responsiveness (NSBR) separately in lifetime nonsmokers, cigarette smokers, and ex-smokers. Occupational exposure to vapors, gas, dust, or fumes, estimated with a job exposure matrix (JEM), was associated with chronic bronchitis among current smokers only (prevalence ratio (PR): 1.2 to 1.7). The interaction of occupational exposure with smoking, however, was not statistically significant (p > 0.1). Self-reported exposure was related to chronic bronchitis in all smoking groups. An increased risk for chronic bronchitis was found in agricultural, textile, paper, wood, chemical, and food processing workers, being more pronounced in smokers. Lung function and NSBR were not clearly related to occupational exposures. Findings were similar for asthmatic and nonasthmatic subjects. In conclusion, occupational exposures contributed to the occurrence of chronic (industrial) bronchitis in young adults. Fixed airflow limitation was not evident, probably due to the relatively young age of this population.     

Obstructive lung disease and low lung function in adults in the United States: data from the National Health and Nutrition Examination Survey, 1988-1994

BACKGROUND: Obstructive lung disease (OLD) is an important cause of morbidity and mortality in the US adult population. Potentially treatable mild cases of OLD often go undetected. This analysis determines the national estimates of reported OLD and low lung function in the US adult population. METHODS: We examined data from the Third National Health and Nutrition Examination Survey (NHANES III), a multistage probability representative sample of the US population. A total of 20,050 US adults participated in NHANES III from 1988 to 1994. Our main outcome measures were low lung function (a condition determined to be present if the forced expiratory volume in 1 second-forced vital capacity ratio was less than 0.7 and the forced expiratory volume in 1 second was less than 80% of the predicted value), a physician diagnosis of OLD (chronic bronchitis, asthma, or emphysema), and respiratory symptoms. RESULTS: Overall a mean (SE) of 6.8% (0.3%) of the population had low lung function, and 8.5% (0.3%) of the population reported OLD. Obstructive lung disease (age-adjusted to study population) was currently reported among 12.5% (0.7%) of current smokers, 9.4% (0.6%) of former smokers, 3.1% (1.1%) of pipe or cigar smokers, and 5.8% (0.4%) of never smokers. Surprisingly, 63.3% (0.2%) of the subjects with documented low lung function had no prior or current reported diagnosis of any OLD. CONCLUSIONS: This study demonstrates that OLD is present in a substantive number of US adults. In addition, many US adults have low lung function but no reported OLD diagnosis, which may indicate the presence of undiagnosed lung disease.     

中国农村慢性阻塞性肺疾病患病及防治现状

目的 了解中国农村慢性阻塞性肺疾病(COPD)患病及防治现况.方法 全国的横断面调查.在中国7个省市(北京市、上海市、广东省、辽宁省、天津市、重庆市和陕西省)的农村地区,采用多阶段整群随机抽样方法 ,在每个地区抽取1个农村镇作为调查点,对年龄≥40岁的人群进行问卷调查和肺功能检测.对[第1秒钟用力呼气容积(FEV1)/用力肺活量(FVC)]×100%<70%者,进行支气管舒张试验.以支气管舒张试验后(FEV1/FVC)×100%<70%作为COPD的诊断标准.结果 (1)有效调查人数为9434人,有效应答率为83.6%,COPD患病率为8.8%,男、女患病率分别为12.8%、5.4%.(2)中国农村地区的吸烟率和生物燃料暴露率高,分别为43.0%、83.1%;戒烟率低(17.5%),只有12.4%的吸烟者接受过戒烟劝导.(3)COPD患者中,只有30.0%的患者曾经诊断过COPD相关的呼吸系统疾病,2.4%的患者曾经检测过肺功能;COPD患者目前吸烟比例高达74.5%,Ⅱ级及Ⅱ级以上COPD患者中,只有7.9%的患者规则用药.结论 中国农村COPD患病率高,防治状况差,迫切需要加强COPD人群防治.     

Increased exhaled nitric oxide in chronic bronchitis: comparison with asthma and COPD

STUDY OBJECTIVES: To test the hypothesis that exhaled nitric oxide (NO) is increased in patients with chronic bronchitis, and to compare the results with exhaled NO in patients with asthma and COPD. STUDY DESIGN: Cross-sectional survey. SETTING AND PATIENTS: Veterans Administration pulmonary function laboratory. Patients (n = 179) were recruited from 234 consecutive patients. Two nonsmoking control groups of similar age, with normal spirometry measurements and no lung disease, were used (18 patient control subjects and 20 volunteers). MEASUREMENTS: Participants completed questionnaires and spirometry testing. Exhaled NO was measured by chemiluminescence using a single-breath exhalation technique. RESULTS: Current smoking status was associated with reduced levels of exhaled NO (smokers, 9. 2 +/- 0.9 parts per billion [ppb]; never and ex-smokers, 14.3 +/- 0. 6 ppb; p < 0.0001). Current smokers (n = 57) were excluded from further analysis. Among nonsmokers, the levels of exhaled NO were significantly higher in patients with chronic bronchitis (17.0 +/- 1. 1 ppb; p = 0.035) and asthma (16.4 +/- 1.3 ppb; p = 0.05) but not in those with COPD (14.7 +/- 1.0 ppb; p = 0.17) when compared with either control group (patient control subjects, 11.1 +/- 1.6 ppb; outside control subjects, 11.5 +/- 1.5 ppb). The highest mean exhaled NO concentration occurred in patients with both chronic bronchitis and asthma (20.2 +/- 1.6 ppb; p = 0.005 vs control subjects). CONCLUSIONS: Exhaled NO is increased in patients with chronic bronchitis. The increase of exhaled NO in patients with chronic bronchitis was similar to that seen in patients with asthma. The highest mean exhaled NO occurred in patients with both chronic bronchitis and asthma. Exhaled NO was not increased in patients with COPD. Although chronic bronchitis and asthma have distinct histopathologic features, increased exhaled NO in patients with both diseases suggests common features of inflammation.     

Poor sensitivity of symptoms in early detection of COPD

The prevalence of chronic obstructive pulmonary disease (COPD) has been increasing. However, COPD is often underdiagnosed. The objective of this study was to determine how many outpatients had persistent airflow limitation and could be diagnosed as COPD by post-bronchodilator spirometry. We also evaluated whether the newly diagnosed patients had any symptoms. All outpatients with liver or general diseases over 40 years old who regularly visited to our hospital were tested for pulmonary function by spirometry. Patients with airflow limitation by the first screening spirometry had further examinations including post-bronchodilator spirometry and chest radiograph by pulmonary specialists. A total of 288 patients accepted a first spirometry. The most common chronic diseases of these patients were chronic hepatitis (33.7%), fatty liver (26.4%), liver cirrhosis (8.3%), diabetes (3.5%) and hypertension (3.1%). Approximately half of the patients had a smoking history. 44 of 288 patients (15.3%) showed airflow limitation by pre-bronchodilator spirometry. Of these, 8 patients did not show airflow limitation by a repeat pre-bronchodilator spirometry nor did 5 patients by post-bronchodilator spirometry. The rest were diagnosed as COPD (80.6%), asthma (16.1%) and bronchiectasis (3.2%). The prevalence of COPD was 8.7%. Approximately half of the patients (13/25, 52.0%) diagnosed as COPD had never complained of any respiratory symptoms. Because symptoms such as dyspnea on exertion, cough and sputum are less sensitive for the diagnosis of COPD, the propagation of spirometry in a general practice/setting should be recommended for establishing the diagnosis rate of COPD rather than relying on the presence of respiratory symptoms.     

Patterns of smoking in Delhi and comparison of chronic respiratory morbidity among beedi and cigarette smokers

Tobacco smoking is common in developing countries including India with beedi and cigarette smoking being the main types. A community-based study carried out to study the chronic respiratory morbidity in the urban areas of Delhi was analyzed to determine the patterns of tobacco smoking and to compare the chronic respiratory morbidity among beedi and cigarette smokers. A random, stratified sample was selected from among the permanent residents, aged above 18 years, from nine clusters in Delhi. A standardized respiratory symptoms questionnaire was administered and clinical examination carried out followed by spirometry. The questionnaire included a detailed smoking history including type of smoking, number of cigarettes smoked per day and number of years the person had smoking. Chronic respiratory morbidity in beedi and cigarette smokers was measured in terms of prevalence of chronic respiratory symptoms (chronic cough, phlegm, breathlessness and wheezing) and by lung function results. It was observed that nearly 40% of adult males were current smokers. Beedi smoking was overall the commonest type of smoking in the community. Cigarette smoking was more common in the higher income groups and among the graduates and postgraduates. Beedi smoking was the main form of smoking among the lower and middle-income groups and among the illiterates and the less educated people. Very few female subjects admitted to smoking. The prevalence of symptomatics (those having one or more of chronic chest symptoms) was significantly higher in beedi smokers as compared to cigarette smokers in those smoking greater than 2.5 pack years. Prevalence of wheezing was however not significantly different. Multiple logistic regression analysis revealed type of smoking to be a significant independent determinant of occurrence of respiratory symptoms with the odds for occurrence of symptoms being 1.67 times greater in beedi smokers as compared to cigarette smokers. Lung function (FEV1/FVC and FEV1% predicted) showed significantly greater airways obstruction in beedi smokers as compared to cigarette smokers. It was concluded that the beedi smoking was as or more likely to cause clinical and functional impairment of lungs compared to cigarette smoking.     

Differences in airway responsiveness to acetaldehyde and methacholine in asthma and chronic bronchitis.

Inhaled acetaldehyde may induce bronchoconstriction in asthmatic subjects and provides a new method to investigate airway responsiveness. The objective of the study was to determine whether acetaldehyde was a more specific stimulus than methacholine in differentiating asthma from chronic bronchitis with or without airflow limitation. Bronchial provocation challenges with methacholine and acetaldehyde were performed in 62 asthmatics and in 59 smokers with chronic bronchitis (32 with chronic bronchitis alone and 27 with chronic bronchitis and coexisting chronic obstructive pulmonary disease (COPD)). The response to both bronchoconstrictor agents was measured by the provocative concentration required to produce a 20% fall in forced expiratory volume in one second (FEV1; PC20). The two types of challenge yielded a similarly high level of sensitivity (100% for methacholine and 92% for acetaldehyde) in revealing airway hyperresponsiveness in asthma. However, bronchoprovocation with acetaldehyde yielded considerably greater specificity (95%) than bronchoprovocation with methacholine (24%) in separating asthma from chronic bronchitis. In subjects with asthma, methacholine and acetaldehyde responsiveness were weakly but significantly correlated (r=0.42, p=0.001) but no correlation was found between airway responsiveness to acetaldehyde and baseline FEV1 (r=0.13, p=0.33). These findings suggest that the demonstration of bronchoconstriction in response to acetaldehyde may be a more specific test than methacholine in the differentiation of asthma from chronic bronchitis. Furthermore, methacholine and acetaldehyde hyperresponsiveness are not reflecting the same pathophysiological process in the airways.     

Prevalence and features of asthma–chronic obstructive pulmonary disease overlap in Northern Italy general population

Objective: There is controversy about the diagnostic criteria, prevalence, symptoms, and spirometry characteristics of asthma–chronic obstructive pulmonary disease (COPD) overlap (ACO). Recent data indicate that the fixed method for diagnosing airway obstruction (AO) may overestimate ACO prevalence in the elderly, and a variable method may be more accurate. We aimed at estimating ACO prevalence in a general population sample and comparing patient and clinical features in subjects with ACO, COPD, and asthma. Methods: We analyzed data from a cross-sectional study estimating COPD prevalence in randomly selected adults aged 20–79 years in Verona, Italy, and estimated prevalence and analyzed characteristics of asthma, COPD, and ACO. ACO was defined as AO (Forced Expiratory Volume in one second–FEV₁/ Forced Vital Capacity–FVC < Lower Limit of Normal–LLN), highly positive bronchodilator test (≥15% increase in FEV₁ and FVC ≥400 mL), and personal self-reported history of physician diagnosed asthma and atopy. Results: One thousand two hundred and thirty-six patients were included; 207 (16.7%) had asthma, COPD, or ACO (mean ages: 61.2, 59.7, and 57.2 years, respectively). The 3 groups had similar clinical and demographic variables; however, spirometry revealed differences between ACO and COPD patients, particularly post-bronchodilator FEV₁ reversibility, which was detected in ACO and asthma patients but not in those with COPD. Conclusion: ACO prevalence in Northern Italy was estimated at 2.1%, in the range of values reported by previous studies. Marked differences between ACO and COPD revealed by spirometry may have important clinical implications in terms of treatment for patients with ACO.     

COPD prevalence in Salzburg, Austria: results from the Burden of Obstructive Lung Disease (BOLD) Study

BACKGROUND: COPD is projected to be the third leading cause of death worldwide by 2020. The Burden of Obstructive Lung Disease initiative was started to measure the prevalence of COPD in a standardized way and to provide estimates of the social and economic burden of disease. METHODS: We surveyed a gender-stratified, population-based sample of 2,200 adults >or= 40 years of age. The findings of prebronchodilator and postbronchodilator spirometry, as well as information on smoking and reported respiratory disease was recorded. Irreversible airflow obstruction was defined as a postbronchodilator FEV(1)/FVC ratio of < 0.70. RESULTS: For 1,258 participants with good-quality postbronchodilator spirometry findings, the overall prevalence of COPD at stage I or higher was 26.1%, and was equal in men and women. The prevalence of COPD stage II or higher (FEV(1)/FVC ratio, < 0.7; FEV(1), < 80% predicted) was 10.7%. The prevalence of COPD stage I+, and COPD stage II+, increased with age and cigarette smoking. A doctor diagnosis of COPD was reported by only 5.6% of participants. CONCLUSION: One quarter of residents of Salzburg County (Austria) who were >or= 40 years of age had at least mild irreversible airflow obstruction. The high prevalence of COPD highlights the impending health-care crisis that will affect many countries as a result of this greatly underappreciated condition.     

Underdiagnosis of chronic obstructive pulmonary disease in Northern Sweden.

OBJECTIVE: To assess underdiagnosis of chronic obstructive pulmonary disease. MATERIAL AND METHODS: Two cross-sectional studies of respiratory symptoms and diseases in two population samples of the same age living in the same areas in northern Sweden were performed 6 years apart. In 1986, 5698 (86%) out of 6610 subjects aged 35-36, 50-51 and 65-66 years responded to a postal questionnaire. In 1992 an identical study was performed, and 5617 subjects (87%) out of 6434 responded. Lung function measurements were performed in stratified samples. RESULTS: Of the subjects diagnosed with chronic bronchitis only 25% in 1986 and 23% in 1992 had been diagnosed prior to the study as having chronic bronchitis, emphysema or chronic obstructive pulmonary disease (COPD). Chronic airflow limitation (CAL), used as a surrogate variable for COPD and defined as FEV1/VC <70% and FEV1 <80% of predicted value, was found in 171 subjects in 1986-1987 (12% of the examined subjects), and 166 subjects in 1993-1994 (11%). In 1986-1987, 26% of the subjects with CAL had been diagnosed as having chronic bronchitis or emphysema prior to the survey, while a diagnosis of either asthma, chronic bronchitis or emphysema, or use of asthma medicines, was found in 58%. The corresponding figures in 1993-1994 were 31% and 63%, respectively. The great majority of the subjects with CAL had recurrent wheeze, dyspnoea and chronic productive cough. CONCLUSION: Approximately 60% of the subjects with chronic airflow limitation had been diagnosed prior to the survey as having asthma, chronic bronchitis or emphysema, or were using asthma medicines. The results were similar in 1986-1987 and 1993-1994.