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Background: There are few long-term clinical follow-up studies of adult-onset asthma. The aim of this article was to study clinical characteristics of adult-onset asthma in relation to remission and persistence of the disease in a 15-year follow-up.

Methods: A cohort of 309 adults aged 20-60 years with asthma onset during the last 12 months verified by bronchial variability, was recruited between 1995 and 1999 from the general population in northern Sweden. The cohort was followed-up in 2003 (n=250) and between 2012 and 2014 (n=205). Structured interviews and spirometry were performed at recruitment and the follow-ups. Bronchial hyperreactivity (BHR) and skin-prick tests were performed at recruitment and blood samples were collected at the last follow-up. Remission of asthma was defined as no asthma symptoms and no use of asthma medication during the last 12 months.

Results: Of eight individuals in remission in 2003, five had relapsed between 2012 and 2014 and in total, 23 (11%) were in remission, while 182 had persistent asthma. Those in remission had higher mean forced expiratory volume in 1 s % predicted at recruitment than those with persistent asthma (94.6 versus 88.3, p=0.034), fewer had severe BHR (27.3% versus 50.9%, p=0.037) and they had less body mass index increase (+1.6 versus +3.0, p=0.054). Of those with persistent asthma, 13% had uncontrolled asthma and they had higher levels of blood neutrophils than those with partly controlled or controlled asthma.

Conclusion: Higher forced expiratory volume in 1 s % predicted and less-severe BHR was associated with remission of adult-onset asthma, but still, the proportion in remission in this 15-year follow-up was low.

Introduction: The prevalence of COPD tends to level off in populations with decreasing prevalence of smoking but the extent of underdiagnosis in such populations needs further investigation. Aim: To investigate underdiagnosis and misclassification of COPD with a focus on socio-economy, lifestyle determinants and healthcare utilization.

Method: The 1839 participants were selected from two ongoing large-scale epidemiological research programs: The Obstructive Lung Disease in Northern Sweden Studies and the West Sweden Asthma Study. COPDGOLD was defined according to the fixed post-bronchodilator spirometric criteria FEV1/FVC<0.70 in combination with respiratory symptoms.

Results: Among the 128 participants who fulfilled the criteria for COPDGOLD, the underdiagnosis was 83.6% (n = 107) of which 57.9% were men. The undiagnosed participants were younger, had higher FEV1% of predicted and less frequently a family history of bronchitis. One in four of the undiagnosed had utilized healthcare and had more frequently utilized healthcare due to a burden of respiratory symptoms than the general population without COPD. Underdiagnosis was not related to educational level. Misclassification of COPD was characterized by being a woman with low education, ever smoker, having respiratory symptoms and having a previous asthma diagnosis.

Conclusion: In the high income country Sweden, the underdiagnosis of COPD was highly prevalent. Reduced underdiagnosis can contribute to risk factor modification, medical treatment and self-management strategies in early stages of the disease, which may prevent disease progression and improve the quality of life among those affected. Therefore, there is a need to increase the use of spirometry in primary care to improve the diagnostic accuracy.

Rationale: Spirometry is essential for diagnosis and assessment of prognosis in COPD.

Objectives: To identify FEV1 trajectories and their determinants, based on annual spirometry measurements among individuals with and without airway obstruction. Furthermore, to assess mortality in relation to trajectories.

Methods: In 2002-04, individuals with airway obstruction (AO) (FEV1/VC<0.70, n=993) and age- and sex-matched non-obstructive (NO) referents were recruited from population-based cohorts. Annual spirometries until 2014 were utilized in joint-survival Latent Class Mixed Models to identify lung function trajectories. Mortality data were collected during 15 years of follow-up.

Results: Three trajectories were identified among the AO-cases and two among the NO referents. Trajectory membership was driven by baseline FEV1%predicted (%pred) in both groups and additionaly, pack-years in AO and current smoking in NO. Longitudinal FEV1%pred level depended on baseline FEV1%pred, pack-years and obesity. The trajectories were distributed: 79.6% T1AO FEV1-high with normal decline, 12.8% T2AO FEV1-high with rapid decline, and 7.7% T3AO FEV1-low with normal decline (mean 27, 72 and 26 mL/year) among AO-individuals, and 96.7% T1NO FEV1-high with normal decline and 3.3% T2NO FEV1-high with rapid decline (mean 34 and 173 mL/year) among referents. Hazard for death was increased for T2AO (HR1.56) and T3AO (HR3.45) vs. T1AO, and for T2NO (HR2.99) vs. T1NO.

Conclusions: Three different FEV1 trajectories were identified among those with airway obstruction and two among the referents, with different outcomes in terms of FEV1-decline and mortality. The FEV1 trajectories among airway obstructive and the relationship between low FVC and trajectory outcome are of particular clinical interest.

Background: The relationship between lung function decline and eosinophils and neutrophils has important therapeutic implications among asthmatics, but it has rarely been studied in large cohort studies.

Objective: The aim is to study the relationship between blood eosinophils and neutrophils and FEV₁ decline in a long-term follow-up of a population-based adult asthma cohort.

Methods: In 2012-2014, an adult asthma cohort was invited to a follow-up including spirometry, blood sampling, and structured interviews, and n = 892 participated (55% women, mean age 59 y, 32-92 y). Blood eosinophils, neutrophils and FEV ₁ decline were analyzed both as continuous variables and divided into categories with different cut-offs. Regression models adjusted for smoking, exposure to vapors, gas, dust, or fumes (VGDF), use of inhaled and oral corticosteroids, and other possible confounders were utilized to analyze the relationship between eosinophils and neutrophils at follow-up and FEV₁ decline.

Results: The mean follow-up time was 18 years, and the mean FEV ₁ decline was 27 ml/year. The annual FEV₁ decline was related to higher levels of both blood eosinophils and neutrophils at follow-up, but only the association with eosinophils remained when adjusted for confounders. Further, the association between FEV₁ decline and eosinophils was stronger among those using ICS. With EOS <0.3 × 10⁹/L as reference, a more rapid decline in FEV1 was independently related to EOS ≥0.4 × 10⁹/L in adjusted analyses.

Conclusions and clinical relevance: Besides emphasizing the importance of smoking cessation and reduction of other harmful exposures, our real-world results indicate that there is an independent relationship between blood eosinophils and FEV₁ decline among adults with asthma.

Background: Chronic airway obstruction (CAO) and restrictive spirometry pattern (RSP) are associated with mortality, but sex-specific patterns of all-cause and specific causes of death have hardly been evaluated.

Objectives: To study the possible sex-dependent differences of all-cause mortality and patterns of cause-specific mortality among men and women with CAO and RSP, respectively, to that of normal lung function (NLF).

Design: Population-based prospective cohort study.

Methods: Individuals with CAO [FEV1/vital capacity (VC) < 0.70], RSP [FEV₁/VC ⩾ 0.70 and forced vital capacity (FVC) < 80% predicted] and NLF (FEV₁/VC ⩾ 0.70 and FVC ⩾ 80% predicted) were identified within the Obstructive Lung Disease in Northern Sweden (OLIN) studies in 2002–2004. Mortality data were collected through April 2016, totally covering 19,000 patient-years. Cox regression and Fine–Gray regression accounting for competing risks were utilized to estimate hazard ratios (HRs) with 95% confidence intervals (CIs) adjusted for age, body mass index, sex, smoking habits and pack-years.

Results: The adjusted hazard for all-cause mortality was higher in CAO and RSP than in NLF (HR, 95% CI; 1.69, 1.31–2.02 and 1.24, 1.06–1.71), and the higher hazards were driven by males. CAO had a higher hazard of respiratory and cardiovascular death than NLF (2.68, 1.05–6.82 and 1.40, 1.04–1.90). The hazard of respiratory death was significant in women (3.41, 1.05–11.07) while the hazard of cardiovascular death was significant in men (1.49, 1.01–2.22). In RSP, the higher hazard for respiratory death remained after adjustment (2.68, 1.05–6.82) but not for cardiovascular death (1.11, 0.74–1.66), with a similar pattern in both sexes.

Conclusion: The higher hazard for all-cause mortality in CAO and RSP than in NLF was male driven. CAO was associated with respiratory death in women and cardiovascular death in men, while RSP is associated with respiratory death, similarly in both sexes.

Background: Risk factors for severe asthma are not well described. The aim was to identify clinical characteristics and risk factors at study entry that are associated with severe asthma at follow-up in a long-term prospective population-based cohort study of adults with asthma.

Methods: Between 1986 and 2001, 2055 adults with asthma were identified by clinical examinations of population-based samples in northern Sweden. During 2012–2014, n = 1006 (71% of invited) were still alive, residing in the study area and participated in a follow-up, of which 40 were identified as having severe asthma according to ERS/ATS, 131 according to GINA, while 875 had other asthma. The mean follow-up time was 18.7 years.

Results: Obesity at study entry and adult-onset asthma were associated with severe asthma at follow-up. While severe asthma was more common in those with adult-onset asthma in both men and women, the association with obesity was observed in women only. Sensitization to mites and moulds, but not to other allergens, as well as NSAID-related respiratory symptoms was more common in severe asthma than in other asthma. Participants with severe asthma at follow-up had lower FEV1, more pronounced FEV1 reversibility, and more wheeze, dyspnea and nighttime awakenings already at study entry than those with other asthma.

Conclusion: Adult-onset asthma is an important risk factor for development of severe asthma in adults, and obesity increased the risk among women. The high burden of respiratory symptoms already at study entry also indicate long-term associations with development of severe asthma.

Background: COPD has increased in prevalence worldwide over several decades until the first decade after the millennium shift. Evidence from a few recent population studies indicate that the prevalence may be levelling or even decreasing in some areas in Europe. Since the 1970s, a substantial and ongoing decrease in smoking prevalence has been observed in several European countries including Sweden. The aim of the current study was to estimate the prevalence, characteristics and risk factors for COPD in the Swedish general population. A further aim was to estimate the prevalence trend of COPD in Northern Sweden from 1994 to 2009.

Methods: Two large random population samples were invited to spirometry with bronchodilator testing and structured interviews in 2009-2012, one in south-western and one in northern Sweden, n = 1839 participants in total. The results from northern Sweden were compared to a study performed 15 years earlier in the same area and age-span. The diagnosis of COPD required both chronic airway obstruction (CAO) and the presence of respiratory symptoms, in line with the GOLD documents since 2017. CAO was defined as post-bronchodilator FEV1/FVC < 0.70, with sensitivity analyses based on the FEV1/FVC < lower limit of normal (LLN) criterion.

Results: Based on the fixed ratio definition, the prevalence of COPD was 7.0% (men 8.3%; women 5.8%) in 2009-2012. The prevalence of moderate to severe (GOLD >= 2) COPD was 3.5%. The LLN based results were about 30% lower. Smoking, occupational exposures, and older age were risk factors for COPD, whereof smoking was the most dominating risk factor. In northern Sweden the prevalence of COPD, particularly moderate to severe COPD, decreased significantly from 1994 to 2009, and the decrease followed a decrease in smoking.

Conclusions: The prevalence of COPD has decreased in Sweden, and the prevalence of moderate to severe COPD was particularly low. The decrease follows a major decrease in smoking prevalence over several decades, but smoking remained the dominating risk factor for COPD.

Highlights:

• Severe obesity strongly associates to blood neutrophils in adult-onset asthma.
• B-neutrophils may partly mediate associations between obesity and asthma control.
• Clinical evaluation of adult-onset asthma should include assessing B-neutrophils.

Background: With increasing prevalence of overweight and obesity, it is important to study how body mass index (BMI) change may affect lung function among subjects with asthma. There are few prospective studies on this topic, especially with separate analyses of those with normal and high BMI. The aim of the present study was to prospectively study the association between annual BMI change and annual lung function decline, separately among those with normal initial BMI and overweight/obesity, in an adult asthma cohort.

Methods: A population-based adult asthma cohort was examined at study entry between 1986 and 2001 and at follow-up between 2012 and 2014 (n=945). Annual BMI change was analysed in association with annual decline in forced expiratory volume in 1 s (FEV1), forced vital capacity (FVC) and FEV1 /FVC separately in those with normal weight (BMI 18.5–24.9) and overweight/obese subjects (BMI ⩾25) at study entry. Regression models were used to adjust for sex, age, smoking, inhaled corticosteroids use and occupational exposure to gas, dust or fumes.

Results: Overweight/obese subjects had lower FEV1 and FVC but slower annual FEV1 and FVC decline compared to those with normal weight. After adjustment through regression modelling, the association between BMI change with FEV1 and FVC decline remained significant for both BMI groups, but with stronger associations among the overweight/obese (FEV1 B[Overweight/obese] =−25 mL versus B[normal weight] = −15 mL). However, when including only those with BMI increase during follow-up, the associations remained significant among those with overweight/obesity, but not in the normal-weight group. No associations were seen for FEV1 /FVC.

Conclusions: BMI increase is associated with faster FEV1 and FVC decline among overweight and obese adults with asthma in comparison with their normal-weight counterparts.

Background: Asthma is a common disease and a major public health concern. Respiratory symptoms are related to its prognosis, which in turn associates with lung function. Still this association on a long-term basis is not entirely understood.

Aim: To study the association of the type and number of respiratory symptoms with FEV 1 and FEV 1 decline in women and men with asthma.

Method: A population-based cohort of adults with asthma was examined at study entry between 1986 and 2001 and at follow-up between 2012 and 2014, and n=977 had valid measurements of FEV 1 on both occasions. Data regarding respiratory symptoms at study entry (recurrent wheeze, dyspnoea, longstanding cough and productive cough) were analysed in relation to FEV 1 and annual decline in FEV 1, both unadjusted and adjusted for other potentially associated factors by linear regression.

Results: For both sexes recurrent wheeze and dyspnoea were associated with lower FEV 1 at study entry and follow-up, while productive cough was associated with lower FEV 1 only at follow-up. No associations were found between the type of symptoms and annual decline in FEV 1. In adjusted analyses, the association between recurrent wheeze and lower FEV 1 both at study entry and follow-up remained significant among women. Also, the association between a higher number of symptoms with lower FEV 1 both at study entry and follow-up were present for both sexes and remained after adjustment.

Conclusions: Particularly recurrent wheeze and a higher number of respiratory symptoms may predict lower lung function also in the long run among women and men with asthma.

Objectives: The aim was to identify predictors of electronic cigarette (e-cigarette) use among teenagers.

Design and setting: A prospective population-based cohort study of schoolchildren in northern Sweden.

Participants: In 2006, a cohort study about asthma and allergic diseases among schoolchildren started within the Obstructive Lung Disease in Northern Sweden studies. The study sample (n=2185) was recruited at age 7–8 years, and participated in questionnaire surveys at age 14–15 and 19 years. The questionnaire included questions about respiratory symptoms, living conditions, upper secondary education, physical activity, diet, health-related quality of life, parental smoking and parental occupation. Questions about tobacco use were included at age 14–15 and 19 years.

Primary outcome: E-cigarette use at age 19 years.

Results: At age 19 years, 21.4% had ever tried e-cigarettes and 4.2% were current users. Among those who were daily tobacco smokers at age 14–15 years, 60.9% had tried e-cigarettes at age 19 years compared with 19.1% of never-smokers and 34.0% of occasional smokers (p<0.001). Among those who had tried e-cigarettes, 28.1% were never smokers both at age 14–15 and 19 years, and 14.4% were never smokers among the current e-cigarette users. In unadjusted analyses, e-cigarette use was associated with daily smoking, use of snus and having a smoking father at age 14–15 years, as well as with attending vocational education, physical inactivity and unhealthy diet. In adjusted analyses, current e-cigarette use was associated with daily tobacco smoking at age 14–15 years (OR 6.27; 95% CI 3.12 to 12.58), attending a vocational art programme (OR 2.22; 95% CI 1.04 to 4.77) and inversely associated with eating a healthy diet (OR 0.74; 95% CI 0.59 to 0.92).

Conclusions: E-cigarette use was associated with personal and parental tobacco use, as well as with physical inactivity, unhealthy diet and attending vocational upper secondary education. Importantly, almost one-third of those who had tried e-cigarettes at age 19 years had never been tobacco smokers.

INTRODUCTION: How e-cigarette use relates to changes in smoking status and respiratory symptoms in the population remains controversial. The aim was to study the association between e-cigarette use and, changes in smoking status and changes in respiratory symptoms.

METHODS: A prospective, population-based study of random samples of the population (age 16–69 years) was performed within The Obstructive Lung Disease in Northern Sweden (OLIN) study and West Sweden Asthma Study (WSAS). A validated postal questionnaire containing identical questions was used in OLIN and WSAS at baseline in 2006–2008 and at follow-up in 2016. In total, 17325 participated on both occasions. Questions about respiratory symptoms and tobacco smoking were included in both surveys, while e-cigarette use was added in 2016.

RESULTS: In 2016, 1.6% used e-cigarettes, and it was significantly more common in persistent tobacco smokers (10.6%), than in those who quit smoking (2.1%), started smoking (7.8%), or had relapsed into tobacco smoking at follow-up (6.4%) (p<0.001). Among current smokers at baseline, tobacco smoking cessation was less common in e-cigarette users than e-cigarette non-users (14.2% vs 47.6%, p<0.001) and there was no association with a reduction in the number of tobacco cigarettes smoked per day. Those who were persistent smokers reported increasing respiratory symptoms. In contrast, the symptoms decreased among those who quit tobacco smoking, but there was no significant difference in respiratory symptoms between quitters with and without e-cigarette use.

CONCLUSIONS: E-cigarette use was associated with persistent tobacco smoking and reporting respiratory symptoms. We found no association between e-cigarette use and tobacco smoking cessation, reduction of number of tobacco cigarettes smoked per day or reduction of respiratory symptoms.

Objective: Education in itself and as a proxy for socioeconomic status, may influence asthma control, but remains poorly studied in adult-onset asthma. Our aim was to study the association between the level of education and asthma control in adult-onset asthma.

Methods: Subjects with current asthma with onset >15 years were examined within the Obstructive Lung Disease in Northern Sweden study (OLIN, n = 593), Seinäjoki Adult Asthma Study (SAAS, n = 200), and West Sweden Asthma Study (WSAS, n = 301) in 2009–2014 in a cross-sectional setting. Educational level was classified as primary, secondary and tertiary. Uncontrolled asthma was defined as Asthma Control Test (ACT) score ≤19. Altogether, 896 subjects with complete data on ACT and education were included (OLIN n = 511, SAAS n = 200 and WSAS n = 185).

Results: In each cohort and in pooled data of all cohorts, median ACT score was lower among those with primary education than in those with secondary and tertiary education. Uncontrolled asthma was most common among those with primary education, especially among daily ICS users (42.6% primary, 28.6% secondary and 24.2% tertiary; p = 0.001). In adjusted analysis, primary education was associated with uncontrolled asthma in daily ICS users (OR 1.92, 95% CI 1.15–3.20). When stratified by atopy, the association between primary education and uncontrolled asthma was seen in non-atopic (OR 3.42, 95% CI 1.30–8.96) but not in atopic subjects.

Conclusions: In high-income Nordic countries, lower educational level was a risk factor for uncontrolled asthma in subjects with adult-onset asthma. Educational level should be considered in the management of adult-onset asthma.

Background: Severe asthma increases the risk of severe COVID-19 outcomes such as hospitalization and death. However, more studies are needed to understand the association between asthma and severe COVID-19.

Methods: A cohort of 150,430 adult asthma patients were identified in the Swedish National Airway Register (SNAR) from 2013 to December 2020. Data on body mass index, smoking habits, lung function, and asthma control test (ACT) were obtained from SNAR, and uncontrolled asthma was defined as ACT ⩽19. Patients with severe COVID-19 were identified following hospitalization or in death certificates based on ICD-10 codes U07.1 and U07.2. The Swedish Prescribed Drug register was used to identify comorbidities and data from Statistics Sweden for educational level. Multivariate logistic regression analyses were used to estimate associations with severe COVID-19.

Results: Severe COVID-19 was identified in 1067 patients (0.7%). Older age (OR = 1.04, 95% CI = 1.03–1.04), male sex (1.42, 1.25–1.61), overweight (1.56, 1.27–1.91), obesity (2.12, 1.73–2.60), high-dose inhaled corticosteroids in combination with long-acting β-agonists (1.40, 1.22–1.60), dispensed oral corticosteroids ⩾2 (1.48, 1.25–1.75), uncontrolled asthma (1.64, 1.35–2.00), cardiovascular disease (1.20, 1.03–1.40), depression (1.47, 1.28–1.68), and diabetes (1.52, 1.29–1.78) were associated with severe COVID-19, while current smoking was inversely associated (0.63, 0.47–0.85). When comparing patients who died from COVID-19 with those discharged alive from hospital until 31 December 2020, older age, male sex, and current smoking were associated with COVID-19 death.

Conclusion: Patients with uncontrolled asthma and high disease burden, including increased asthma medication intensity, should be identified as risk patients for severe COVID-19. Furthermore, current smoking is strongly associated with COVID-19 death in asthma.

Background: Patients with obstructive lung diseases may be at risk of hospitalization and/or death due to COVID-19.

Aim: To estimate the frequency of severe COVID-19, and COVID-19-related mortality in a well-defined large population of patients with asthma and chronic inflammatory lung disease (COPD). Further to assess the frequency of asthma and COPD as registered comorbidities at discharge from hospital, and in death certificates.

Methods: At the start of the pandemic, the Swedish National Airway Register (SNAR) included 271,404 patients with a physician diagnosis of asthma and/or COPD. In September 2020, after the first COVID-19 wave in Sweden, the database was linked with the National Patient Register (NPR), the Swedish Intensive Care Register and the Swedish Cause of Death Register, which all provide data about COVID-19 based on International Classification of Diseases (ICD-10) codes. Severe COVID-19 was defined as hospitalization and/or intensive care or death due to COVID-19.

Results: Among patients in SNAR, 0.5% with asthma, and 1.2% with COPD were identified with severe COVID-19. Among patients  < 18 years with asthma, only 0.02% were severely infected. Of hospitalized adults, 14% with asthma and 29% with COPD died. Further, of patients in SNAR, 56% with asthma and 81% with COPD were also registered in the NPR, while on death certificates the agreement was lower (asthma 24% and COPD 71%).

Conclusion: The frequency of severe COVID-19 in asthma and COPD was relative low. Mortality for those hospitalized was double as high in COPD compared to asthma. Comorbid asthma and COPD were not always identified among patients with severe COVID-19.

Introduction: Assessing COVID-19 risk in asthma patients is challenging due to disease heterogeneity and complexity. We hypothesized that potential risk factors for COVID-19 may differ among asthma age groups, hindering important insights when studied together.

Methods: We included a population-based cohort of asthma patients from the Swedish National Airway Register (SNAR) and linked to data from several national health registers. COVID-19 outcomes included infection, hospitalization, and death from Jan 2020 until Feb 2021. Asthma patients were grouped by ages 12–17, 18–39, 40–64, and ≥65 years. Characteristics of asthma patients with different COVID-19 outcomes were compared with those in their age-corresponding respective source population.

Results: Among 201,140 asthma patients studied, 11.2% were aged 12–17 years, 26.4% 18–39, 37.6% 40–64, and 24.9% ≥65 years. We observed 18,048 (9.0%) COVID-19 infections, 2172 (1.1%) hospitalizations, and 336 (0.2%) COVID-19 deaths. Deaths occurred only among patients aged ≥40. When comparing COVID-19 cases to source asthma populations by age, large differences in potential risk factors emerged, mostly for COVID-19 hospitalizations and deaths. For ages 12–17, these included education, employment, autoimmune, psychiatric, and depressive conditions, and use of short-acting β-agonists (SABA) and inhaled corticosteroids (ICS). In the 18–39 age group, largest differences were for age, marital status, respiratory failure, anxiety, and body mass index. Ages 40–64 displayed notable differences for sex, birth region, cancer, oral corticosteroids, antihistamines, and smoking. For those aged ≥65, largest differences were observed for cardiovascular comorbidities, type 1 diabetes, chronic obstructive pulmonary disease, allergic conditions, and specific asthma treatments (ICS-SABA, ICS-long-acting bronchodilators (LABA)). Asthma control and lung function were important across all age groups.

Conclusion: We identify distinct differences in COVID-19-related risk factors among asthma patients of different ages. This information is essential for assessing COVID-19 risk in asthma patients and for tailoring patient care and public health strategies accordingly.

Rationale: Evidence on risk factors for Coronavirus disease 2019 (COVID-19) outcomes among patients with COPD in relation to COVID-19 vaccination remains limited. The objectives of the present study were to characterise determinants of COVID-19 infection, hospitalisation, intensive care unit (ICU) admission and death in COPD patients in their unvaccinated state compared to when vaccinated.

Methods: We included all COPD patients in the Swedish National Airway Register (SNAR). Events of COVID-19 infection (test and/or healthcare encounter), hospitalisation, ICU admission and death were identified from 1 January 2020 to 30 November 2021. Using adjusted Cox regression, associations between baseline sociodemographics, comorbidities, treatments, clinical measurements and COVID-19 outcomes, during unvaccinated and vaccinated follow-up time, were analysed.

Results: The population-based COPD cohort included 87 472 patients, among whom 6771 (7.7%) COVID-19 infections, 2897 (3.3%) hospitalisations, 233 (0.3%) ICU admissions and 882 (1.0%) COVID-19 deaths occurred. During unvaccinated follow-up, risk of COVID-19 hospitalisation and death increased with age, male sex, lower education, non-married status and being foreign-born. Comorbidities increased risk of several outcomes, e.g. respiratory failure for infection and hospitalisation (adjusted hazard ratios (HR) 1.78, 95% CI 1.58–2.02 and 2.51, 2.16–2.91, respectively), obesity for ICU admission (3.52, 2.29–5.40) and cardiovascular disease for mortality (2.80, 2.16–3.64). Inhaled COPD therapy was associated with infection, hospitalisation and death. COPD severity was also associated with COVID-19, especially hospitalisation and death. Although the risk factor panorama was similar, COVID-19 vaccination attenuated HRs for some risk factors.

Conclusion: This study provides population-based evidence on predictive risk factors for COVID-19 outcomes and highlights the positive implications of COVID-19 vaccination for COPD patients.

Background and Objective: Uncontrolled asthma in patients treated for mild/moderate disease could be caused by non-pulmonary treatable traits (TTs) that affect asthma control negatively. We aimed to identify demographic characteristics, behavioural (smoking) and extrapulmonary (obesity, comorbidities) TTs and the risk for future exacerbations among patients with uncontrolled asthma prescribed step 1–3 treatment according to the Global Initiative for Asthma (GINA).

Methods: Twenty-eight thousand five hundred eighty-four asthma patients (≥18 y) with a registration in the Swedish National Airway Register between 2017 and 2019 were included (index-date). The database was linked to other national registers to obtain information on prescribed drugs 2-years pre-index and exacerbations 1-year post-index. Asthma treatment was classified into step 1–3 or 4–5, and uncontrolled asthma was defined based on symptom control, exacerbations and lung function.

Results: GINA step 1–3 included 17,318 patients, of which 9586 (55%) were uncontrolled (UCA 1–3). In adjusted analyses, UCA 1–3 was associated with female sex (OR 1.34, 95% CI 1.27–1.41), older age (1.00, 1.00–1.00), primary education (1.30, 1.20–1.40) and secondary education (1.19, 1.12–1.26), and TTs such as smoking (1.25, 1.15–1.36), obesity (1.23, 1.15–1.32), cardiovascular disease (1.12, 1.06–1.20) and depression/anxiety (1.13, 1.06–1.21). Furthermore, UCA 1–3 was associated with future exacerbations; oral corticosteroids (1.90, 1.74–2.09) and asthma hospitalization (2.55, 2.17–3.00), respectively, also when adjusted for treatment step 4–5.

Conclusion: Over 50% of patients treated for mild/moderate asthma had an uncontrolled disease. Assessing and managing of TTs such as smoking, obesity and comorbidities should be conducted in a holistic manner, as these patients have an increased risk for future exacerbations.

Introduction: Swedish guidelines adhere to the international GOLD document regarding management of chronic obstructive pulmonary disease (COPD). Based on data from the Swedish National Airway Register (SNAR) the aim was to evaluate adherence to guidelines of pharmacological treatment of COPD in Swedish primary and secondary care.

Methods: During a period of 18 months, data on symptoms (CAT, mMRC), lung function, exacerbation history and pharmacological treatment from 15,595 COPD patients from 853 primary care and 125 secondary care clinics were collected from SNAR. Patients with a co-diagnosis of asthma were excluded. Patients were divided into four treatment groups: no pharmacological treatment, short-acting bronchodilators alone, long-acting bronchodilators alone and ICS alone or in combination with bronchodilators.

Results: Of the patients, 29% were in GOLD group A, 58% in group B, 2% in group C and 11% in group D. CAT score was ≥10 and mMRC score was below 2 in 30.9% of the patients and mMRC score was ≥2 and CAT score <10 in 4.2% of the patients. In 61.4% of the patients, no exacerbation was registered during the last year. Long-acting bronchodilators were prescribed for 78% and ICS for 46% of all patients. In groups A, B, C and D, respectively, 21%, 11%, 11% and 5% did not receive any inhaler therapy; 67%, 81%, 81% and 90% received long-acting bronchodilators; 33%, 46%, 55% and 71% received any ICS containing therapy and 19%, 34%, 39% and 61% received triple therapy.

Discussion: Data from the SNAR indicate that only a minority of COPD patients were untreated. There was a liberal use of ICS containing drug combinations in subjects who do not have an indication for ICS. A considerable proportion of subjects at high risk of exacerbations did not receive ICS treatment.

Background: In 2019, WHO estimated COPD to be the third leading cause of death in the world. However, COPD is probably underestimated as cause of death due to the well-known under-diagnosis.

Aim: To evaluate the proportion of and factors associated with COPD recorded as cause of death in a long-term follow-up of a population-based COPD cohort.

Methods: The study population includes all individuals (n = 551) with COPD defined as chronic airway obstruction (post-bronchodilator FEV1/FVC<0.70) + respiratory symptoms identified after re-examinations of four population-based cohorts. Mortality and underlying or contributing cause of death following ICD-10 classification were collected from the Swedish National Board of Health and Welfares register from date of examination in 2002–04 until 2016.

Results: The study sample consisted of 32.3% GOLD 1, 55.9% GOLD 2, and 11.8% GOLD 3–4. The mean follow-up time was 10.3 (SD3.77) years and the cumulative mortality 45.0%. COPD (ICD-10 J43-J44) was recorded on 28.2% (n = 70) of the death certificates (11.1%, 25.7% and 57.1% by GOLD stage), whereof n = 35 had COPD recorded as underlying and n = 35 as contributing cause of death. To have COPD recorded as cause of death was independently associated with ex- and current smoking and a self-reported physician diagnosis of COPD, while male sex, overweight/obesity and higher FEV1% of predicted associated with the absence.

Conclusions: COPD was largely underreported cause of death. Even among those with severe/very severe disease, COPD was only mentioned on 57.1% of the death certificates.

Purpose: Patient education in chronic obstructive pulmonary disease (COPD) is recommended in treatment strategy documents, since it can improve the ability to cope with the disease. Our aim was to identify the extent of and factors associated with patient education in patients with COPD in a primary health care setting.

Patients and Methods: In this nationwide study, we identified 29,692 COPD patients with a registration in the Swedish National Airway Register (SNAR) in 2019. Data on patient education and other clinical variables of interest were collected from SNAR. The database was linked to additional national registers to obtain data about pharmacological treatment, exacerbations and educational level.

Results: Patient education had been received by 44% of COPD patients, 72% of whom had received education on pharmacological treatment including inhalation technique. A higher proportion of patients who had received education were offered smoking cessation support, had performed spirometry and answered the COPD Assessment Test (CAT), compared with patients without patient education. In the adjusted analysis, GOLD grade 2 (OR 1.29, 95% CI 1.18–1.42), grade 3 (OR 1.41, 95% CI 1.27–1.57) and grade 4 (OR 1.79, 95% CI 1.48–2.15), as well as GOLD group E (OR 1.17, 95% CI 1.06–1.29), ex-smoking (OR 1.70, 95% CI 1.56–1.84) and current smoking (OR 1.45, 95% CI 1.33–1.58) were positively associated with having received patient education, while cardiovascular disease (OR 0.92, 95% CI 0.87–0.98) and diabetes (OR 0.93, 95% CI 0.87–1.00) were negatively associated with receipt of patient education.

Conclusion: Fewer than half of the patients had received patient education, and the education had mostly been given to those with more severe COPD, ex-and current smokers and patients with fewer comorbidities. Our study highlights the need to enhance patient education at an earlier stage of the disease.

BACKGROUND: Restrictive lung function may indicate various underlying diseases. The aim of this study was to evaluate the accuracy of different restrictive spirometry patterns (RSPs) to identify restrictive lung function (total lung capacity [TLC] < lower limit of normal [LLN]) according to reference values by the Global Lung Function Initiative (GLI) in a wide age-ranged, general population sample.

METHODS: A general population sample (n = 607, age 23-72 years, smokers 18.8%) with proper dynamic spirometry and TLC measurements, was included. Accuracy of two main categories of RSP to identify TLC < LLN were evaluated: traditional RSPs (definition 1: FVC < 80% of predicted and FEV₁ /FVC ≥ 0.7 and definition 2: FVC < LLN and FEV₁ /FVC ≥ LLN) and RSPs defined by Youden's method (definition 3: FVC < 85.5% of predicted and FEV₁ /FVC ≥ LLN and definition 4: FVC Z-score < -1.0 and FEV₁ /FVC ≥ LLN).

RESULTS: The prevalence of restrictive lung function (TLC < LLN) was 5.3%. The most accurate cut-offs for FVC to identify TLC < LLN were 85.5% for FVC% of predicted, and -1.0 for FVC Z-score. The traditional RSP definitions 1 and 2 had higher specificity (95.0% and 96.9%) but substantially lower sensitivity compared to RSP definitions 3 and 4.

CONCLUSION: Based on the GLI reference values, the RSP definition FVC < LLN and FEV₁ /FVC ≥ LLN yielded the highest specificity and may appropriately be used to rule out restrictive lung function. The RSP definition with the most favourable trade-off between sensitivity and specificity, FVC < 85.5% of predicted and FEV₁ /FVC ≥ LLN, may serve as an alternative with higher sensitivity for screening.

Background: Patients with uncontrolled asthma should be evaluated for medication adherence. This study aimed to identify characteristics associated with poor adherence to inhaled corticosteroids (ICS) and to explore adherence prior to treatment escalation.

Methods: This nationwide longitudinal cohort study included adult asthma patients (n = 30880) with a healthcare visit including Asthma Control Test (ACT) and registered in the Swedish National Airway Register between 1 July 2017 and 28 February 2019 (index date). Patient data was crosslinked to other national registers. Treatment steps two years pre- and one year post-index, were identified by prescribed drugs. Poor adherence was defined as Medication Possession Ratio <80 %.

Results: Poor adherence was identified in 73 % of patients in treatment steps 2–5, where of 35 % had uncontrolled asthma (ACT≤19). In adjusted models, poor adherence was associated with better disease control; ACT≤19 (OR 0.78, 95 % CI 0.71–0.84), short-acting β2-agonist (SABA) overuse (0.69, 0.61–0.79) and exacerbations (0.79, 0.70–0.89) in steps 2–3. Among patients with uncontrolled asthma, poor adherence was associated with SABA overuse (1.71, 1.50–1.95), exacerbations (1.29, 1.15–1.46), current smoking (1.38, 1.21–1.57) and inversely associated with asthma management education (0.85, 0.78–0.93. Similar results were observed in steps 4–5. When investigating post-index treatment, 53 % remained stationary, 30 % stepped down and 17 % escalated treatment. Prior to escalation, 49 % had poor adherence.

Conclusions: Poor ICS adherence was associated with better asthma control. Among uncontrolled patients, poor adherence was associated with SABA overuse and exacerbations. Our result highlights the importance of asthma management education to improve adherence in uncontrolled patients.

Background: The prevalence of asthma has increased both among children and adults during the latter half of the 20th century. The prevalence among adults is affected by the incidence of asthma not only in childhood but also in adulthood. Time trends in asthma incidence have been poorly studied.

Aims: The aim of this study was to review the incidence of adult-onset asthma from 1996 to 2006 and 2006 to 2016 and compare the risk factor patterns.

Methods: In the Obstructive Lung Disease in Northern Sweden (OLIN) studies, two randomly selected population-based samples in the 20–69-year age group participated in postal questionnaire surveys about asthma in 1996 (n=7104, 85%) and 2006 (n=6165, 77%). A 10-year follow-up of the two cohorts with the same validated questionnaire was performed, and 5709 and 4552 responded, respectively. Different definitions of population at risk were used in the calculations of asthma incidence. The protocol followed a study performed between 1986 and 1996 in the same area.

Results: The crude incidence rate of physician-diagnosed asthma was 4.4 per 1000 person-years (men 3.8, women 5.5) from 1996 to 2006, and 4.8 per 1000 person-years (men 3.7, women 6.2) from 2006 to 2016. When correcting for possible under-diagnosis at study entry, the incidence rate was 2.4 per 1000 person-years from 1996 to 2006 and 2.6 per 1000 person-years from 2006 to 2016. The incidence rates were similar across age groups. Allergic rhino-conjunctivitis was the main risk factor for incident asthma in both observation periods (risk ratio 2.4–2.6).

Conclusions: The incidence of adult-onset asthma has been stable over the last two decades and has remained at a similar level since the 1980s. The high incidence contributes to the increase in asthma prevalence.

Background: A high participation rate is warranted in order to ensure validity in surveys of the general popu-lation. However, participation rates in such studies have declined during the last decades. Objective: To evaluate the reasons for and potential effects of non-response in a large population-based survey about asthma and respiratory symptoms in Northern Sweden.

Methods: Within the Obstructive Lung Disease In Norrbotten (OLIN) studies, a random sample of 12,000 adults aged 20-79 was invited to a postal questionnaire survey about asthma, allergic rhino-conjunctivitis and respiratory symptoms in 2016. Three reminders were sent. A random sample of 500 non-responders was invited to a telephone interview.

Results: The participation rate in the initial mailing was 41.4%, and 9.2%, 5.0%, and 2.6% in the subsequent three reminders and totally 58.3% (n 1/4 6854) responded. Of 500 non-responders selected for telephone interviews, 320 were possible to reach and 272 participated. Male sex, younger age, and current smoking were associated with both late and non-response. The prevalence of asthma and most respiratory symptoms did not differ significantly between responders and non-responders while allergic rhino-conjunctivitis and smoking was more common among non-responders. Reminders increased the participation rate but did not alter risk ratios for smoking and occupational exposures. Reasons for non-response were mainly lack of time and having forgotten to answer.

Conclusions: With a response rate of 58.3%, neither the prevalence estimates of asthma, respiratory symptoms nor the associations to risk factors were affected by non-response, while allergic rhino-conjunctivitis and smoking was underestimated in this Swedish population.

Objective: Low socioeconomic status based both on educational level and income has been associated with asthma and respiratory symptoms, but changes over time in these associations have rarely been studied. The aim was to study the associations between educational or income inequality and asthma and respiratory symptoms among women and men over a 20-year period in northern Sweden.

Methods: The study was performed within the Obstructive Lung disease in Northern Sweden (OLIN) research program. Mailed questionnaire surveys were administered to a random sample of adults (20-69 years of age) living in Sweden, in 1996, 2006 and 2016. Data on educational level and income were collected from the national integrated database for labor market research.

Results: The educational inequality associated with asthma and asthmatic wheeze tended to decrease from 1996 to 2016, while it increased for productive cough, the latter among men not among women. The income inequality decreased for productive cough, especially for women, while no clear overall trends were found for asthmatic wheeze and asthma, apart from a decrease in income inequality regarding asthma among men.

Conclusion: The patterns for socioeconomic inequality differed for asthma and wheeze compared to productive cough, and the results emphasize that education and income do not mirror the same aspects of socioeconomic inequality in a high-income country. Our findings are important for decision makers, not the least on a political level, as reduced inequality, e.g. through education, could lead to reduced morbidity.

Objective: Asthma control is of importance when assessing the risk of severe outcomes of COVID-19. The aim of this study was to explore associations of clinical characteristics and the effect of multiple manifestations of uncontrolled asthma with severe COVID-19.

Methods: In 2014–2020, adult patients with uncontrolled asthma, defined as Asthma Control Test (ACT) ≤19 were identified in the Swedish National Airway Register (SNAR) (n = 24533). The SNAR database, including clinical data, was linked with national registers to identify patients with severe COVID-19 (n = 221). The effect of multiple manifestations of uncontrolled asthma was based on: 1) ACT ≤15, 2) frequent exacerbations and 3) previous asthma inpatient/secondary care and evaluated stepwise. Poisson regression analyses were conducted with severe COVID-19 as the dependent variable.

Results: In this cohort with uncontrolled asthma, obesity was the strongest independent risk factor for severe COVID-19 in both sexes, but even greater in men. Multiple manifestations of uncontrolled asthma were more common among those with severe COVID-19 vs. without: one, 45.7 vs. 42.3%, two, 18.1 vs. 9.1% and three, 5.0 vs. 2.1%. The risk ratio (RR) of severe COVID-19 increased with an increasing number of manifestations of uncontrolled asthma: one, RR 1.49 (95% CI 1.09–2.02), two, RR 2.42 (95% CI 1.64–3.57) and three, RR 2.96 (95% CI 1.57–5.60), when adjusted for sex, age, and BMI.

Conclusions: It is important to consider the effect of multiple manifestations of uncontrolled asthma and obesity when assessing patients with COVID-19, as this increases the risk of severe outcomes substantially.

Background: Chronic obstructive pulmonary disease (COPD) is considered a heterogenic syndrome with systemic effects, including muscle dysfunction. There is evidence of postural control impairments among individuals with COPD, partly related to muscle weakness. However, research is scarce regarding the other underlying systems of postural control, such as the visual, somatosensory and vestibular system. The aim was to compare postural control, as well as the motor and sensory systems, between individuals with and without COPD. Methods: Twenty-two participants with COPD (mean age 74.0 ±6.2 years) and 34 non-obstructive references (mean age 74.9 ±4.9 years) participated in this cross-sectional study. Postural control was assessed with center of pressure trajectory of postural sway in quiet as well as a limits of stability test, calculating mediolateral and anteroposterior amplitudes for each test. Assessment of function in the motor system included maximum hand grip strength, as well as maximum strength in muscles around the hip, knee and ankle joints. Visual acuity, pressure sensibility, proprioception, vestibular screening, and reaction time were also included. Data was compared between groups, and significant differences in postural control were further analyzed with an orthogonal projection of latent structures regression model. Results: There was a significantly increased sway amplitude in the mediolateral direction in quiet stance on soft surface with eyes open (p = 0.014) as well as a smaller anteroposterior amplitude in the limits of stability test (p = 0.019) in the COPD group. Regression models revealed that the mediolateral amplitude was related to visual acuity and the burden of tobacco smoking assessed as pack-years. Further, muscle strength associated with anteroposterior amplitude in limits of stability test in the COPD group, and with age and ankle dorsal flexion strength among the referents. Besides for lower ankle plantar flexion strength in the COPD group, there were however no significant differences in muscle strength. Conclusions: Individuals with COPD had a decreased postural control and several factors were associated with the impairments. The findings imply that the burden of tobacco smoking and reduced visual acuity relate to increased postural sway in quiet stance, and that muscle weakness is related to decreased limits of stability, among individuals with COPD.

Objective: To study asthma exacerbations, healthcare utilization and health status among subjects with asthma with different treatment regimens and levels of asthma control.

Methods: In 2012-2014, n = 1425 adults from a population-based asthma cohort within the OLIN studies (Obstructive Lung disease in Northern Sweden) were invited to a follow-up including spirometry and a structured interview, n = 1006 participated. Asthma Control Test (ACT) was used to detect uncontrolled asthma, and physical and mental dimensions of health were measured with SF-8. Pharmacological treatment use was classified by Global Initiative for Asthma treatment steps. Out of n = 830 with current asthma, n = 714 answered ACT (57% women, 32-92 years) and were included in the study.

Results: Uncontrolled asthma increased per treatment step (no treatment 9.9%, treatment step 1-3 24.1%, and treatment steps 4-5 39.9%, p < 0.001). A higher proportion of subjects with uncontrolled asthma reported exacerbations, healthcare utilization, and worse health status than those with controlled asthma. The proportion of subjects reporting exacerbations, healthcare visits, emergency room visits and regular follow-up visits increased per treatment step. Worse health was associated with uncontrolled asthma, but not with the level of treatment. A higher proportion of women than men reported exacerbations, any healthcare visits, and lower health. Regular follow-up visits to a physician were uncommon (women 21.2% vs. men 14.6%, p = 0.022).

Conclusions: Uncontrolled asthma is common in all treatment steps, and is associated with worse health status. However, health status did not differ by treatment steps. Identifying subjects with uncontrolled asthma regardless of treatment regimens should be a priority, thus follow-up visits are important.

Background: The Swedish National Airway Register (SNAR) was initiated in 2013 to ensure and improve the quality of care for patients with asthma and COPD.

Aim: To describe the development and design of SNAR, and to study the 2019 data to evaluate its potential utility related to improvement of quality of care.

Methods: SNAR includes data from patients with asthma (both children and adults) and COPD from primary, secondary and tertiary care, and also, for COPD inpatient care. Data on diagnostic investigations (e.g. spirometry, blood sample, skin prick test), symptom-scores, comorbidities and prescribed treatments are registered. The registrations are entered manually by healthcare professionals, or directly transferred from electronic medical records to a web-based platform.

Results: In 2019, 1000 clinics participated and data were directly transferred by about 88% of them. The register included data on 205,833 patients with asthma and 80,372 with COPD (of these, 5% had both diagnoses). Registrations of new patients and follow-up visits from primary and secondary/tertiary care in 2019 were completed for 75,707 patients with asthma (11,818 children <12 yr, 6545 adolescents 12–17 yr, and 57,344 adults >17 yr) and 38,117 with COPD. Depending on age and disease group, 43–77% had performed spirometry, 36–65% Asthma Control Test, and 60% COPD Assessment Test. The prevalence of current smoking was about 2% in adolescents, 10% in adults with asthma, and 34% in COPD. For these, smoking cessation support was offered to 27%, 38% and 51%, respectively. Overall, limited data were available on investigation of allergy, 6-min walk test, patient education and written treatment plans. Regarding asthma, sex-differences in disease management were evident.

Conclusion: SNAR has cumulatively registered data from over 270,000 individuals, and the register is important for patients, caregivers, authorities, politicians and researchers to evaluate the effect of treatment and to ensure high and equal quality of care nationwide.

Background: The Swedish National Airway Register (SNAR) was initiated to improve and ensure quality of care for patients with asthma and COPD.

Aim: To describe the register design of SNAR and unique patients between the years of 2014 until 2019.

Methods: SNAR has been ongoing since 2013 and includes patients with asthma (both children and adults) and COPD from primary and secondary care (both in- and outpatients). Data about healthcare provider, symptoms, comorbidities, additional investigations (i.e. spirometry) and prescribed treatment is registered. The registrations are performed manually by healthcare professionals, or directly transmitted from medical records to a web-based platform.

Results: In 2019, 853 primary care clinics, 125 secondary care clinics (whereof 62 pediatric clinics) and 24 inpatient wards were linked to the register. Data was directly transmitted from medical records of about 80% of the clinics, and manually by 20%. The register includes in total 205833 unique patients with asthma and 80372 with COPD. Registrations of new patients and follow-up visits in 2019 applied 73788 patients with asthma (58% women, mean age 44yr) whereof 10190 were <11yr and 6248 were 12-17yr, 33276 with COPD (57% women, mean age 73yr), and 5013 with both asthma and COPD (ACO) (61% women, mean age 71yr). In COPD, the proportion of patients in GOLD 1-4 were; GOLD1 15%, GOLD2 55%, GOLD3 25% GOLD4 5%. During 2019, 1506 registered patients with asthma and 3791 with COPD died.

Conclusion: The SNAR has cumulatively registered over 280000 individuals and provides a unique insight into the care of patients with asthma and COPD in Sweden.

Background: Uncontrolled asthma (UCA) is different from severe asthma and can be identified in children across all ranges of prescribed treatment.

Objective: Our aim was to characterize uncontrolled childhood asthma in pediatric specialist care.

Methods: We performed a nationwide cross-sectional study of 5497 children (aged 6-17 years) with asthma who were treated by pediatricians at outpatient clinics during 2019 and registered in the Swedish National Airway Register. UCA was defined as an Asthma Control Test score of 19 or lower and/or 2 or more exacerbations in the past year and/or an FEV1 value less than 80% predicted. Treatment was categorized from step 1 to step 5 according to the Global Initiative for Asthma.

Results: UCA was identified in 1690 children (31%), of whom 64% had an Asthma Control Test score of 19 or lower, 20% had recurrent exacerbations, and 31% had an FEV1 value less than 80% predicted. UCA was associated with female sex (odds ratio [OR] = 1.29 [95% CI = 1.15-1.45]), older age (OR = 1.02 [95% CI = 1.00-1.04]), obesity (OR = 1.43 [95% CI = 1.12-1.83]), and more treatment using steps 1 and 2 as a reference (step 3, OR = 1.28 [95% CI = 1.12-1.46]); steps 4-5, OR = 1.32 [95% CI = 1.10-1.57]). UCA in children prescribed treatment steps 1 and 2 (group UCA1-2) occurred in 28% of all children at this treatment step (n = 887). Children in group UCA1-2 had exacerbations more frequently than did those children with UCA who were prescribed steps 4 and 5 treatment (24% vs 15% [P =.001]).

Conclusion: UCA was common and associated with female sex, increasing age, obesity, and higher Global Initiative for Asthma treatment step. Surprisingly, UCA was also common in children prescribed less than the maximum treatment, and those children could be considered undertreated patients.

Background: Asthma and obesity are prevalent conditions that are increasing worldwide. Asthma is characterized by airway inflammation and bronchial variability, while obesity is a complex metabolic disorder that poses significant morbidity and mortality risks. Obesity is a risk factor for asthma and a plethora of other non-communicable diseases.

Objective: To compare all-cause and cause-specific mortality between obese, overweight and normal weight adults with asthma in a cohort with long-term follow-up.

Methods: Individuals from a population-based adult asthma cohort recruited in Norrbotten county, Sweden, were clinically examined between 1986 and 2001 and grouped into body mass index (BMI) categories. Underlying causes of death until December 31st, 2020 were categorized as cardiovascular, respiratory, cancer and other mortality by linking cohort data to the Swedish National Board of Health and Welfare's National Cause of Death register. Hazard ratios (HR) with 95% confidence intervals (CI) for all-cause and cause-specific mortality associated with overweight and obesity were calculated via Cox proportional hazard models.

Results: In total, 940 individuals were normal weight, 689 overweight and 328 obese while only 13 were underweight. Obesity increased the hazard for all-cause (HR 1.26, 95% CI 1.03–1.54) and cardiovascular mortality (HR 1.43, 95% CI 1.03–1.97). Obesity was not significantly associated with respiratory or cancer mortality. Overweight did not increase the hazard of all-cause or any cause-specific mortality category.

Conclusion: Obesity, but not overweight, was significantly associated with increased hazard of all-cause and cardiovascular mortality in adults with asthma. Neither obesity nor overweight were associated with increased hazard of respiratory mortality.