Prevalence, clinical characteristics and morbidity of the Asthma-COPD overlap in a general population sample.

OBJECTIVE: Although asthma and chronic obstructive pulmonary disease (COPD) have been regarded as distinct conditions, emerging literature suggests that overlapping phenotypes, called asthma-COPD overlap (ACO), exists. The aim of this study was to describe prevalence, patient characteristics and morbidity of ACO. METHODS: From a cross-sectional population sample, the West Sweden Asthma Study, subjects with suspected asthma, chronic bronchitis or COPD, and a random sample, were invited to clinical examinations. ACO was defined as doctor-diagnosed asthma, or clear clinical signs of asthma at examination, with a FEV1/FVC < 0.7. RESULTS: Subjects were categorized as ACO (N = 181), COPD only (N = 89), asthma only (N = 651) or healthy (n = 1036) based on clinical examinations. Prevalence of ACO was 3.4% in the random sample (N = 1172) and 18.1% among asthmatics (N = 138) in the random sample. Subjects with ACO (mean age 59 years, 54% women) had an age and gender distribution in between asthma only (45 years, 63% women) and COPD only (62 years, 41% women). Ever-smoking was reported by 71%, 48% and 74% in the ACO, asthma only and COPD only groups, respectively. Subjects with ACO had worse lung function (mean FEV1% of predicted normal 76%) than asthma only (100%) and COPD only (87%) and reported more respiratory symptoms. Also respiratory related emergency visits were more common in ACO compared to asthma only and COPD only, respectively. CONCLUSIONS: ACO is present in 3.4% of the population and common among subjects with both asthma and COPD. Subjects with ACO had worse lung function and more symptoms than subjects with asthma or COPD only.

Chronic bronchitis in West Sweden - a matter of smoking and social class.

BACKGROUND: Although chronic bronchitis is associated with impaired quality of life, hospitalisations and increased mortality, it has been less in focus after the introduction of the term chronic obstructive pulmonary disease (COPD). There are no recent published data on the prevalence of chronic bronchitis from the Scandinavian countries. AIM: The main aim of the present study was to estimate the prevalence of chronic bronchitis in West Sweden by using data from a large-scale epidemiological study of the general population. A further aim was to identify current risk factors for chronic bronchitis in a population with a major decrease in the proportion of smokers. METHODS: From the 18,087 questionnaire responders out of 30,000 invited to participate at the West Sweden Asthma Study, 2,000 subjects were randomly selected and invited to detailed clinical examinations performed during 2009-2013. A total of 1,172 subjects aged 17-79 participated in the examinations which included, among others, spirometry and structured interviews. Chronic bronchitis was defined according to reported symptoms. RESULTS: The overall prevalence of chronic bronchitis was 7.2% (men 7.6%; women 6.8% ns), and it was 8.7% in subjects older than age 60. Chronic bronchitis was strongly associated with smoking, defined both as current smoking status and pack-years. Other risk factors were increasing age, low socio-economic class and urban living. Of those with chronic bronchitis, 22% fulfilled the GOLD criteria of COPD. CONCLUSION: The prevalence of chronic bronchitis was somewhat lower than found by studies in Sweden in the 1980s and the prevalence was now similar in men and women. Although smoking was still the dominating risk factor for chronic bronchitis, the relative importance of smoking had decreased parallel with a decreasing smoking prevalence, while the relative importance of other factors than smoking had increased compared to previous studies.

Different risk factor patterns for adult asthma, rhinitis and eczema: results from West Sweden Asthma Study.

BACKGROUND: Atopic diseases including asthma, rhinitis and eczema have increased in the second half of the past century. This has been well studied among children and adolescents but with the exception of asthma to a much lesser extent in adults. The adult risk factor pattern of atopic diseases, in particular of eczema, and their relation to allergic sensitization are yet to be fully elucidated. Studies among adults that have compared the risk factor pattern for these conditions in the same material are very few. The objective of this study was to compare the risk factor patterns for asthma, rhinitis and eczema in a randomly selected adult population. METHODS: A questionnaire survey on atopic diseases was dispatched by mail to 30,000 randomly selected individuals in West Sweden aged 16-75 years and 62 % participated. A subgroup of 2000 individuals was selected for clinical examinations including blood sampling for specific serum Immunoglobulin E to common airborne allergens and 1172 attended. RESULTS: The prevalence of current asthma was 11.8 %, current rhinitis 42.8 %, current eczema 13.5 and 2.3 % had all three conditions while 13.9 % had at least two conditions. No mutual risk factor was identified for all three conditions. Allergic sensitization was a strong risk factor for current asthma (OR 4.1 CI 2.7-6.3) and current rhinitis (OR 5.1 CI 3.8-6.9) but not so for current eczema. Obesity was a risk factor for current asthma and current rhinitis, while farm childhood decreased the risk for current asthma and current rhinitis. Occupational exposure to gas dust or fumes and female sex was associated with an increased risk of current asthma and current eczema. CONCLUSIONS: There are different risk factor patterns for asthma, rhinitis and eczema in adults but some risk factors are overlapping between some of the conditions. The effect of mutable risk factors should be assessed further in longitudinal studies.

Prevalence and risk factors of COPD among never-smokers in two areas of Sweden - Occupational exposure to gas, dust or fumes is an important risk factor.

BACKGROUND: Although active tobacco smoking is the main risk factor for COPD, COPD is not uncommon also among never-smokers. Different study locations along with different spirometric definitions of COPD have historically yielded different prevalence estimates of the disease. AIM: To study current prevalence and risk factors of COPD among never-smokers in two areas of Sweden. METHODS: Data collected in 2008-2012 within the West Sweden Asthma Study and Obstructive Lung Disease in Northern Sweden Studies was pooled. The study population consisted of 1839 subjects who participated in spirometry and interviews. COPD was defined as post-bronchodilator a) FEV(1)/(F)VC < 0.7, b) FEV(1)/FVC < 0.7 and c) FEV(1)/FVC < lower limit of normal. RESULTS: Of the 1839 subjects, 967 (52.6%) were never-smokers. Among the never-smoking subjects, the prevalence of COPD according to definitions a-c was 7.7%, 4.9% and 3.0%, respectively. The corresponding prevalence of GOLD grade ≥2 was 2.0%, 1.4% and 1.3%. No significant difference in prevalence between the two study areas was observed. In never-smokers, occupational exposure to gas, dust or fumes (GDF) was significantly associated with both COPD (OR 1.85, 95% CI 1.03-3.33), and GOLD ≥2 (OR 4.51, 1.72-11.9) according to definition a), after adjusting for age, educational level and exposure to passive smoking at work. CONCLUSION: Depending on definition, prevalence of COPD among never-smokers was 3.0-7.7%, whereas GOLD ≥2 was present in 1.3-2.0%. Occupational exposure to GDF remained independently and significantly associated with COPD regardless of spirometric definition of the disease.

Passive smoking exposure is associated with increased risk of COPD in never smokers.

BACKGROUND: Passive smoking, or environmental tobacco smoke (ETS), is a risk factor for lung cancer, cardiovascular disease, and childhood asthma, but a relationship with COPD has not been fully established. Our aim was to study ETS as a risk factor for COPD in never smokers. METHODS: Data from three cross-sectional studies within the Obstructive Lung Disease in Northern Sweden (OLIN) database were pooled. Of the 2,182 lifelong never smokers, 2,118 completed structured interviews and spirometry of acceptable quality. COPD was defined according to the GOLD (Global Initiative for Chronic Obstructive Lung Disease) criteria using postbronchodilator spirometry. The association of COPD with ETS in single and multiple settings was calculated by multivariate logistic regression adjusting for known risk factors for COPD. RESULTS: COPD prevalence was associated with increased ETS exposure: 4.2% (no ETS), 8.0% (ETS ever at home), 8.3% (ETS at previous work), and 14.7% (ETS ever at home and at both previous and current work), test for trend P = .003. Exclusion of subjects aged ≥ 65 years and subjects reporting asthma yielded similar results. ETS in multiple settings, such as ever at home and at both previous and current work, was strongly associated to COPD (OR, 3.80; 95% CI, 1.29-11.2). CONCLUSIONS: In this population-based sample of never smokers, ETS was independently associated with COPD. The association was stronger for ETS in multiple settings. ETS in multiple settings was, after age, the strongest risk factor for COPD and comparable to personal smoking of up to 14 cigarettes/d in comparable materials. The findings strongly advocate measures against smoking in public places.

COPD among non-smokers - report from the obstructive lung disease in Northern Sweden (OLIN) studies.

BACKGROUND: In westernized countries smoking and increasing age are the most important risk factors for COPD. Prevalence and risk factors of COPD among non-smokers are not well studied. AIM: To study the prevalence and risk factors of COPD among non-smokers and to determine the proportion of non-smokers among subjects with COPD. METHODS: A random sample of 2470 subjects drawn from a population-based postal survey of 10,040 (85-88% participation) adults (aged 20-77) in Norrbotten, Sweden, were invited to structured interviews and lung function tests, and 1897 participated. COPD was classified using the fixed ratio (GOLD) definition and for comparison the lower limit of normal (LLN). RESULTS: The prevalence of airway obstruction was 6.9% among non-smokers and strongly age related. The prevalence of GOLD stage ≥II among non-smokers was 3.5%. Both among subjects with airway obstruction and among subjects with GOLD stage ≥II, the proportions of non-smokers were 20%. Of men with airway obstruction, 14.1% were non-smokers versus 26.8% among women. Non-smokers with GOLD stage ≥II had significantly more symptoms and higher co-morbidity than non-smokers without airway obstruction. Sex, area of domicile and exposure to environmental tobacco smoke was not significantly associated to airway obstruction among non-smokers. Using LLN for defining airway obstruction yielded a similar prevalence. CONCLUSION: The prevalence of airway obstruction among non-smokers was close to 7% and was associated with increasing age. One out of seven men with airway obstruction, defined using the fixed ratio, versus one out of four women had never smoked.