SummaryBackground: During the latter half of the 20th century, the prevalence of asthma and many other allergic diseases has increased. Information on asthma prevalence trends among adults after 2010, especially regarding studies separating allergic asthma from non-allergic asthma, is lacking.Objective: The aim was to estimate prevalence trends of current asthma among adults, both allergic and non-allergic, from 1996 to 2016. while the prevalence of non-allergic asthma remained stable around 3.4%-3.8%. The increase in current asthma was most pronounced among women and among the middle-aged. Physician-diagnosed asthma, asthma medication use and ARC also increased significantly, while the prevalence of symptoms common in asthma such as wheeze and attacks of shortness of breath decreased slightly or was stable. The prevalence of current smoking decreased from 27.4% in 1996 to 12.3% in 2016. Conclusions and Clinical Relevance:The prevalence of allergic asthma increased from 1996 to 2006 and further to 2016, while the prevalence of non-allergic asthma remained on a stable prevalence level. The prevalence of symptoms common in asthma decreased slightly or was stable despite a substantial decrease in the prevalence of current smoking. Clinicians should be aware that the previously observed increase in prevalence of allergic asthma is still ongoing.

BackgroundSmoking is considered to be the single most important preventable risk factor for respiratory symptoms. Estimating prevalence of respiratory symptoms is important since they most often precede a diagnosis of an obstructive airway disease, which places a major burden on the society. The aim of this study was to estimate prevalence trends of respiratory symptoms and asthma among Swedish adults, in relation to smoking habits. A further aim was to estimate the proportion of respiratory symptom and asthma prevalence attributable to smoking.MethodsData from two large-scale cross-sectional surveys among adults performed in northern Sweden in 1996 and 2006 were analysed. Identical methods and the same questionnaire were used in both surveys. The association between smoking, respiratory symptoms and asthma was analysed with multiple logistic regression analyses. Changes in prevalence of respiratory symptoms and asthma from 1996 to 2006 were expressed as odds ratios. Additionally, the population attributable risks of smoking were estimated.ResultsThe prevalence of most respiratory symptoms decreased significantly from 1996 to 2006. Longstanding cough decreased from 12.4 to 10.1%, sputum production from 19.0 to 15.0%, chronic productive cough from 7.3 to 6.2%, and recurrent wheeze from 13.4 to 12.0%. Any wheeze and asthmatic wheeze remained unchanged. This parallels to a decrease in smoking from 27.4 to 19.1%. In contrast, physician-diagnosed asthma increased from 9.4 to 11.6%. The patterns were similar after correction for confounders. All respiratory symptoms were highly associated with smoking, and the proportion of respiratory symptoms in the population attributed to smoking (PAR) ranged from 9.8 to 25.5%. In 2006, PAR of smoking was highest for recurrent wheeze (20.6%).ConclusionsIn conclusion, we found that respiratory symptoms, in particular symptoms common in bronchitis, decreased among adults in northern Sweden, parallel to a decrease in smoking from 1996 to 2006. In contrast, the prevalence of physician-diagnosed asthma increased during the same time-period. Up to one fourth of the respiratory symptom prevalence in the population was attributable to smoking.

BACKGROUND AND OBJECTIVE: To date, a limited number of population-based studies have prospectively evaluated the remission of childhood asthma. This work was intended to study the remission and persistence of childhood asthma and related factors. METHODS: In 1996, a questionnaire was distributed to the parents of all children aged 7 to 8 years in 3 municipalities in northern Sweden, and 3430 (97%) participated. After a validation study, 248 children were identified as having asthma; these children were reassessed annually until age 19 years when 205 (83%) remained. During the follow-up period lung function, bronchial challenge testing, and skin prick tests were performed. Remission was defined as no use of asthma medication and no wheeze during the past 12 months as reported at endpoint and in the 2 annual surveys preceding endpoint (ie, for ≥3 years). RESULTS: At age 19 years, 21% were in remission, 38% had periodic asthma, and 41% persistent asthma. Remission was more common among boys. Sensitization to furred animals and a more severe asthma (asthma score ≥2) at age 7 to 8 years were both inversely associated with remission, odds ratio 0.14 (95% confidence interval 0.04–0.55) and 0.19 (0.07–0.54), respectively. Among children with these 2 characteristics, 82% had persistent asthma during adolescence. Asthma heredity, damp housing, rural living, and smoking were not associated with remission. CONCLUSIONS: The probability of remission of childhood asthma from age 7- to 8-years to age 19 years was largely determined by sensitization status, particularly sensitization to animals, asthma severity, and female gender, factors all inversely related to remission.

Summary Background Severe asthma is a considerable challenge for patients, health‐care professionals and society. Few studies have estimated the prevalence of severe asthma according to modern definitions of which none based on a population study. Objective To describe characteristics and estimate the prevalence of severe asthma in a large adult population‐based asthma cohort followed for 10‐28 years. Methods N = 1006 subjects with asthma participated in a follow‐up during 2012‐14, when 830 (mean age 59 years, 56% women) still had current asthma. Severe asthma was defined according to three internationally well‐known criteria: the ATS workshop definition from 2000 used in the US Severe Asthma Research Programme (SARP), the 2014 ATS/ERS Task force definition and the GINA 2017. All subjects with severe asthma according to any of these criteria were undergoing respiratory specialist care and were also contacted by telephone to verify treatment adherence. Results The prevalence of severe asthma according to the three definitions was 3.6% (US SARP), 4.8% (ERS/ATS Taskforce), and 6.1% (GINA) among subjects with current asthma. Although all were using high ICS doses and other maintenance treatment, >90% did not have controlled asthma according to the asthma control test. Severe asthma was related to age >50 years, nasal polyposis, impaired lung function, sensitization to aspergillus, and tended to be more common in women. Further, neutrophils in blood significantly discriminated severe asthma from other asthma. Conclusions and Clinical Relevance Severe asthma differed significantly from other asthma in terms of demographic, clinical and inflammatory characteristics, results suggesting possibilities for improved treatment regimens of severe asthma. The prevalence of severe asthma in this asthma cohort was 4%‐6%, corresponding to approximately 0.5% of the general population.

Changes in both prevalence and risk factor patterns of COPD were observed between surveys. Following a continuing decrease in smoking habits over several decades, a decrease in the prevalence of moderate to severe COPD was observed from 1994 to 2009 in northern Sweden.

The use of electronic cigarettes has increased exponentially since its introduction onto the global market in 2006. However, short- and long-term health effects remain largely unknown due to the novelty of this product. The present study examines the acute effects of e-cigarette aerosol inhalation, with and without nicotine, on vascular and pulmonary function in healthy volunteers. Seventeen healthy subjects inhaled electronic cigarette aerosol with and without nicotine on two separate occasions in a double-blinded crossover fashion. Blood pressure, heart rate, and arterial stiffness measured by pulse wave velocity and pulse wave analysis were assessed at baseline, and then at 0 h, 2 h, and 4 h following exposure. Dynamic spirometry and impulse oscillometry were measured following vascular assessments at these time points, as well as at 6 h following exposure. e-Cigarette aerosol with nicotine caused a significant increase in heart rate and arterial stiffness. Furthermore, e-cigarette aerosol-containing nicotine caused a sudden increase in flow resistance as measured by impulse oscillometry, indicating obstruction of the conducting airways. Both aerosols caused an increase in blood pressure. The present study indicates that inhaled e-cigarette aerosol with nicotine has an acute impact on vascular and pulmonary function. Thus, chronic usage may lead to long-term adverse health effects. Further investigation is warranted.Electronic supplementary materialThe online version of this article (10.1007/s12012-019-09516-x) contains supplementary material, which is available to authorized users.

Key Points Question Who uses electronic cigarettes (e-cigarettes), and is there an association between e-cigarette use and respiratory symptoms? Findings In a random sample of more than 30 000 Swedish adults, e-cigarette use was most common among current smokers, and the prevalence of respiratory symptoms was highest among the current smokers who also used e-cigarettes. Meaning Longitudinal studies will be essential to further determine the long-term health effects of e-cigarette use and whether in dual users it increases the burden of respiratory conditions or encourages sustainable smoking cessation.

Background-Although sensitization to indoor allergens is strongly associated with asthma, there are questions as to how this relates to asthma symptoms.