Is asthma in children still increasing? 20-year prevalence trends in northern Sweden.

BACKGROUND: In the present study, we describe prevalence trends of asthma and investigate the association with asthma symptoms, use of asthma medication, and asthma severity among 8-year-old children in Norrbotten, Sweden in 1996, 2006, and 2017. METHODS: Within the Obstructive Lung Disease in Northern Sweden (OLIN) studies, three pediatric cohorts were recruited in 1996, 2006, and 2017 respectively. Identical methods were used; all children in first and second grade (median age 8 years) in three municipalities were invited to a parental questionnaire survey, completed by n = 3430 in 1996 (97% participation), n = 2585 in 2006 (96%), and n = 2785 in 2017 (91%). The questionnaire included questions about respiratory symptoms and diagnosis, treatment, and severity of asthma. RESULTS: The prevalence of wheezing was stable during the study, 10.1% in 1996; 10.8% in 2006; and 10.3% in 2017, p = .621, while physician-diagnosed asthma increased: 5.7%, 7.4%, and 12.2%, p < .001. The use of asthma medication in the last 12 months increased: 7.1%, 8.7%, and 11.5%, p < .001. Among children diagnosed with asthma, the prevalence of asthma symptoms, the impact on daily life, and severe asthma decreased, while the use of inhaled corticosteroids increased from 1996 until 2017. CONCLUSION: The prevalence of wheezing was stable among 8-year-old in this area from 1996 to 2017, while the prevalence of physician-diagnosed asthma doubled but without an increase in asthma morbidity. The increase of physician-diagnosed asthma without a coincident increase in asthma morbidity can partly be explained by more and earlier diagnosis among those with mild asthma.

Prevalence and risk factors for allergic sensitization: 3 cross-sectional studies among schoolchildren from 1996 to 2017.

Background: The prevalence of allergic sensitization and allergic diseases has increased for decades in Northern Europe, but recent studies are lacking. Objective: We sought to study the prevalence trends of allergic sensitization, associated risk factors, and the association with asthma and allergic rhinitis (AR) among children in Northern Sweden. Methods: Three cohorts of children aged 7 to 8 years participated in a skin prick test (SPT) with 10 airborne allergens in 1996, 2006, and 2017, with 2148, 1693, and 1762 participants tested, respectively, representing 87% to 90% of schoolchildren in the catchment communities. Adjusted Poisson regression was used to identify risk factors for allergic sensitization and the association with asthma and AR. Results: The prevalence of any positive SPT response increased from 21% in 1996 to 30% in 2006 and remained at 30% in 2017 (P < .001). Sensitization to cat was the most common for all the years. The risk factor pattern for a positive SPT response was similar in all examinations, with positive and significant associations with a family history of allergy (risk ratio, 1.4-1.5) and negative and significant associations with having a cat at home (risk ratio, 0.7-0.8). The prevalence of physician-diagnosed asthma increased, but the association with allergic sensitization weakened. The opposite trends were found for AR-decreasing prevalence and strengthened association with allergic sensitization. Conclusions: The prevalence of allergic sensitization increased from 1996 to 2006 but plateaued in the next decade, whereas the risk factor pattern remained stable. The diverging trends of associations between allergic sensitization and asthma and AR suggest secular trends in the clinical management of allergic diseases.

Maternal Stress, Early Life Factors and Infant Salivary Cortisol Levels.

BACKGROUND: Salivary cortisol (SC), a commonly used biomarker for stress, may be disrupted by negative events in pregnancy, at birth and in infancy. We aimed to explore if maternal perceived stress (PSS) in or after pregnancy and SC levels in pregnancy were associated with SC in early infancy, and, secondly, to identify early life factors associated with infants' SC levels (iSC). METHODS: At 3 months of age, SC was analyzed in 1057 infants participating in a Nordic prospective mother-child birth cohort study. Maternal PSS was available from questionnaires at 18- and 34-week gestational age (GA) and 3-month post-partum, and SC was analyzed at 18-week GA. Early life factors included sociodemographic and infant feeding from questionnaires, and birth data from medical charts. Associations to iSC were analyzed by Spearman correlation and multinomial logistic regression analyses. RESULTS: In this exploratory study neither PSS at any time point nor maternal SC (mSC) were associated with iSC. Higher birth weight was associated with higher levels of iSC, while inverse associations were observed in infants to a mother not living with a partner and mixed bottle/breastfeeding. CONCLUSIONS: Maternal stress was not associated with iSC levels, while birth weight, single motherhood and infant feeding may influence iSC levels.

Early-life risk factors for development of asthma from 8 to 28†years of age: a prospective cohort study.

Background: The objective was to estimate the incidence rate of asthma from age 8 to 28 years and evaluate early-life risk factors for asthma onset at different ages. Methods: In 1996, within the Obstructive Lung Disease in Northern Sweden (OLIN) studies, a cohort of 3430 schoolchildren (97% of invited) was recruited at age 8 years to a prospective study about asthma. The cohort was followed annually from age 8 to 19 years and at 28 years by questionnaire surveys (67% of the original cohort participated). Asthma was categorised as never-asthma, onset age ≤8 years, onset age 9-13 years, onset age 14-19 years or onset age >19 years. Results: Of the 3430 individuals in the cohort, 690 (20.1%) reported asthma in any survey. The average incidence rate was 10.0/1000 per year at ≤8 years, 11.9/1000 per year at 9-13 years, 13.3/1000 per year at 14-19 years and 6.1/1000 per year at >19 years. The incidence was higher among boys until age 10 years, but from age 15 years, it became higher among girls. Family history of asthma, allergic sensitisation and breastfeeding <3 months were associated with asthma onset throughout the study. Low birthweight, maternal smoking during pregnancy, severe respiratory infection, rhinoconjunctivitis and eczema were associated with asthma onset ≤8 and 9-13 years. Conclusions: The incidence of asthma was high during childhood and the teenage period, and decreased substantially during young adulthood. Early-life factors were associated with asthma onset throughout childhood but had also a lasting effect on asthma incidence until adulthood.

The Majority of Children Sensitized Before School-Age Develop Allergic Disease Before Adulthood: A Longitudinal Population-Based Study.

BACKGROUND: Allergic sensitization increases the risk of asthma and allergic rhinitis, but the impact of age at onset of sensitization is less studied. OBJECTIVE: To examine the cumulative incidence of asthma and rhinitis up to age 19 years in relation to age at onset of sensitization to airborne allergens. METHOD: All children in grade 1 and 2 (median age, 8 years) in 2 municipalities in Northern Sweden were invited to undergo skin prick tests and answer a questionnaire about allergic diseases, and 88% participated. At ages 12 and 19 years, the protocol was repeated, and 1510 individuals participated in all 3 examinations. Specific IgE data were collected in a random sample at age 19 years (n = 770). Onset of sensitization was defined: 8 years or less, 8 to 12 years, 12 to 19 years, and never sensitized. Adjusted Poisson regression was used to calculate risk ratios (RRs). RESULTS: At 19 years, those sensitized at 8 years of age or earlier had the highest risk of asthma (RR, 4.68; 95% CI, 3.15-6.97) and rhinitis (RR, 22.3; 95% CI, 13.3-37.6), and 84% had developed either asthma or rhinitis. The combination of sensitization at age 8 years or earlier and family history of allergic diseases rendered high risks for asthma (RR, 10.6; 95% CI, 6.71-16.7) and rhinitis (RR, 36.3; 95% CI, 18.9-69.7). Individuals sensitized at age 8 years or earlier showed significantly highest level of sensitization, as judged by number of positive skin test results and titers of specific IgE. CONCLUSIONS: Most individuals with sensitization at age 8 years or earlier developed asthma or rhinitis before young adulthood. The high level of sensitization in those sensitized early contributes to the high incidence of allergic airway conditions.

Asthma increased in young adults from 2008-2016 despite stable allergic rhinitis and reduced smoking.

BACKGROUND: Studies have produced inconsistent results on prevalence trends in asthma and allergic rhinitis (AR). We surveyed young adults about asthma in 2008 and 2016 and examined the impact of gender, AR and smoking. METHODS: Thirty-thousand randomly selected subjects aged 16-75 years in Western Sweden received postal questionnaires in 2008 and 50,000 in 2016. This study is based on responders aged 16-25 years, 2,143 in 2008 and 2,484 in 2016. RESULTS: From 2008-2016 current asthma increased from 9.3% to 11.5% (p = 0.014) and was significant in males without AR (aOR 1.83, 95% CI 1.09-3.07) and male smokers (aOR 3.02, 95% CI 1.12-8.13). In both years the risk of current asthma was reduced by growing up on a farm (aOR 0.26, 95% CI 0.81-0.84 and aOR 0.47, 95% CI 0.23-0.996), independent of a family history of asthma or allergy. AR did not differ significantly from 2008-2016 (22.5% vs 24.4%, p = 0.144). Current smoking decreased from 20.3% to 15.2% (p<0.001), especially in females (23.5% to 16.2%, p<0.001). Female smokers started smoking later and smoked fewer cigarettes in 2016 than 2008. In 2016, 4.8% of the cohort reported using electronic cigarettes. Of those, 60.7% also smoked tobacco and more than two-thirds who used both (67.2%) were heavy smokers. CONCLUSION: Current asthma increased in respondents aged 16-25 from 2008-2016, mainly among males without AR and male smokers. Current AR levelled off in this young population, while current smoking decreased among females.

Shorter time to clinical decision in work-related asthma using a digital tool.

PEF curves are a useful but cumbersome tool in diagnosing work-related asthma. Using a digital spirometer and smartphone app, time to clinical decision could be shortened by 6-7 weeks. Physician's time spent analysing PEF data is also shortened. https://bit.ly/3d5SY78.

Cohort profile: the West Sweden Asthma Study (WSAS): a multidisciplinary population-based longitudinal study of asthma, allergy and respiratory conditions in adults.

PURPOSE: The West Sweden Asthma Study (WSAS) is a population-representative longitudinal study established to: (1) generate data on prevalence trends, incidence and remission of asthma, allergy and respiratory conditions, (2) elucidate on the risk and prognostic factors associated with these diseases, (3) characterise clinically relevant phenotypes of these diseases and (4) catalyse relevant mechanistic, genomic, genetic and translational investigations. PARTICIPANTS: WSAS comprised of randomly selected individuals aged 16 to 75 years who are followed up longitudinally. The first stage involved a questionnaire survey (>42 000 participants) and was undertaken in 2008 and 2016. A random sample (about 8000) of participants in the initial survey undergoes extensive clinical investigations every 8 to 10 years (first investigations in 2009 to 2012, second wave currently ongoing). Measurements undertaken at the clinical investigations involve structured interviews, self-completed questionnaire on personality traits, physical measurements and extensive biological samples. FINDINGS TO DATE: Some of our key findings have shown a 54% increase in the use of asthma medications between the 1990s and 2000s, primarily driven by a five-fold increase in the use of inhaled corticosteroids. About 36% of asthmatics expressed at least one sign of severe asthma indicator, with differential lung performance, inflammation and allergic sensitisation among asthmatics with different signs of severe asthma. Multi-symptom asthmatics were at greater risk of having indicators of severe asthma. In all adults, being raised on a farm was associated with a decreased risk of allergic sensitisation, rhinitis and eczema, but not asthma. However, among adolescents (ie, those 16 to 20 years of age), being raised on a farm decreased the risk of asthma. Personality traits were associated with both beliefs of asthma medication and adherence to treatment. FUTURE PLANS: Follow-up of the cohort is being undertaken every 8 to 10 years. The repeated clinical examinations will take place in 2019 to 2022. The cohort data are currently being linked to routine Swedish healthcare registers for a continuous follow-up. Mechanistic, genomic, genetic and translational investigations are ongoing.

Changes in the prevalence of asthma and respiratory symptoms in western Sweden between 2008 and 2016.

BACKGROUND: Asthma is a common chronic inflammatory disease of the airways, with a noticeable increase in prevalence during the second half of the 20th century. Recent studies assessing the prevalence trends among adults have been inconsistent. We investigated the changes in the prevalence of asthma, respiratory symptoms, and risk factors between 2008 and 2016 in western Sweden. METHODS: The West Sweden Asthma Study (WSAS) is a population-based study which started in 2008 (WSAS I) and then repeated in 2016 (WSAS II) in western Sweden. Randomly selected individuals aged 16-75 years (N = 18 087 in 2008 and N = 24 534 in 2016) completed a questionnaire regarding obstructive lung diseases, respiratory symptoms, potential risk factors, and also questions from the GA2 LEN survey. RESULTS: The prevalence of reported ever asthma, physician-diagnosed asthma, use of asthma medication, and current asthma increased significantly from 9.6% to 11%, 8.3% to 10%, 8.6% to 9.8%, and 8.1% to 9.1%, respectively, between 2008 and 2016. There were also increases in the prevalence of respiratory symptoms during the same period. The greatest increase occurred in young adults aged 16-25 years. Female gender, allergic rhinitis, obesity, and family history of asthma remained the strongest risk factors for asthma in 2016 as it was in 2008. CONCLUSION: There were moderate increases in asthma and respiratory symptoms in adults in western Sweden between 2008 and 2016, the greatest increase occurring in younger adults. The potential risk factors for asthma remained the same during the study period.

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.

Increase in Allergic Sensitization in Schoolchildren: Two Cohorts Compared 10 Years Apart.

BACKGROUND: Time trends of incidence of allergic sensitization are unknown and recent trends of prevalence and risk factors are lacking. OBJECTIVE: To estimate the incidence, prevalence, remission, risk factors, and time trends for allergic sensitization among schoolchildren followed from age 7 to 8 years to age 11 to 12 years. METHODS: In 2006, all children in grades 1 and 2 aged 7 to 8 years in 2 municipalities in northern Sweden were invited to a questionnaire survey and to skin prick testing to 10 common airborne allergens. The cohort was reexamined in 2010, with additional blood sampling for specific IgE. Participation rates were 90% (n = 1700) at age 7 to 8 years and 85% (n = 1657) at age 11 to 12 years. The results were compared with a cohort examined by identical methods 10 years earlier. RESULTS: The prevalence of positive skin prick test result to any allergen increased from 30% at age 7 to 8 years to 41% at age 11 to 12 years (P < .001). The cumulative 4-year incidence was 18%, while remission was low. Sensitization to pollen and furred animals was most common. A family history of allergy was significantly associated with incident sensitization, whereas the presence of furred animals at home was negatively associated. The prevalence at age 7 to 8 years and at age 11 to 12 years and the 4-year incidence were all significantly higher compared with the cohort examined 10 years earlier. CONCLUSIONS: The prevalence of allergic sensitization increased by age as a consequence of a high incidence and a low remission. The trends of increasing incidence and prevalence among schoolchildren imply future increases in the prevalence of allergic diseases.

Only severe COPD is associated with being underweight: results from a population survey.

Low body mass index (BMI) and malnutrition in chronic obstructive pulmonary disease (COPD) are associated with a poor prognosis. The prevalence of underweight, as well as overweight, in severity grades of COPD is sparsely investigated in studies of the general population and the associated patterns of risk factors are not well established. The aim of the present study was to determine the association between severity grades of airflow limitation in COPD, and both underweight and obesity when corrected for possible confounding factors. The study is based on pooled data from the OLIN (Obstructive Lung Disease in Northern Sweden) studies. Complete records with lung function, BMI and structured interview data were available from 3942 subjects (50.7% women and 49.3% men). COPD and severity grading were defined using the Global Initiative for Chronic Obstructive Lung Disease criteria. In sensitivity analyses, the lower limit of normal was used. The prevalence of underweight was 7.3% in severe COPD (grades 3 and 4) versus 2.0% in those with normal spirometry. The prevalence of obesity increased from 9.7% in grade 1, to 16.3% in grade 2 and 20.0% in severe COPD, versus 17.7% in those with normal spirometry. In adjusted analysis, of the COPD severity grades, only severe COPD was associated with underweight (OR 3.24, 95% CI 1.0004-10.5), while the COPD severity grades tended to be inversely associated with overweight.

Relevance of specific IgE antibody titer to the prevalence, severity, and persistence of asthma among 19-year-olds in northern Sweden.

BACKGROUND: Although sensitization to indoor allergens is strongly associated with asthma, there are questions as to how this relates to asthma symptoms. OBJECTIVE: We sought to study the relevance of IgE antibodies to cat and dog allergens in an area in which (1) the climate discourages cockroach, fungal, and mite growth and (2) dander allergens are known to be present in schools and houses without animals. METHODS: IgE to 8 allergens was tested in 963 sera from a population-based study on 19-year-olds, and associations with asthma symptoms, diagnosis, and treatment were examined. In positive sera IgE to specific cat and dog allergens was also assayed. RESULTS: IgE specific for animal dander had the highest prevalence and strongest relationship to asthma diagnosis. Furthermore, asthma severity, as judged by the frequency of symptoms and use of treatment, was directly associated with the titer of IgE antibodies to animal dander. Among the 103 subjects who had current asthma at age 19 years, 50 had asthma before age 12 years. Among those 50, the odds ratios for asthma related to any IgE antibodies to animal dander or high-titer IgE antibodies (≥17.5 IU/mL) were 9.2 (95% CI, 4.9-17) and 13 (95% CI, 6.9-25), respectively. In multivariable analysis IgE antibodies to Fel d 1 and Can f 5 were each associated with current asthma. CONCLUSION: High-titer IgE antibodies to cat and dog allergens were strongly associated with the diagnosis, severity, and persistence of asthma; however, a large proportion of patients with current asthma did not live in a house with a cat or dog.

Juniors' voice at the ERS International Congress, Amsterdam 2015: Juniors' Voice.

Junior member activities at the ERS International Congress 2015 http://ow.ly/R2oIn.

How to optimise patient and public involvement in your research: Doing science.

This paper considers how best to achieve patient and public involvement in research and how to get the most out of it http://ow.ly/R0hwV.

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.

The second year has been completed: News from the Underground.

Among many other things, the last European Respiratory Society (ERS) International Congress in Munich brought changes to the ERS Junior Members Committee (JMC). The 3-year term of JMC representatives has seen Indre Butiene, who initiated the Committee 3 years ago, finish her tenure as chair, with Anders Bjerg, respiratory epidemiologist from Gothenburg, Sweden, being elected as her replacement. Indre's departure has also led to the election of a new representative to the ERS Education Council. We congratulate Agnes Boots from the Netherlands on her election to this important position! Also, here in Breathe, the Doing Science series has been taken over by Georgia Hardavella, UK, whose ideas will take this practical educational series to new levels in 2015. The Hot Topics section is now coordinated by Neil Saad, UK, one of many Juniors outside the JMC who have volunteered for different JMC activities.

Doing Science: managing colleagues and collaborations in scientific research.

Talent, dedication and organisational skills play a pivotal role in the success of scientific and clinical research. However, your capacity to flourish and succeed is often affected by your professional relationships with your peers and bosses. Throughout your career, you will be faced (if not already) with a variety of awkward interpersonal situations. This is the point where sophisticated management skills are required to tackle difficulties and smooth out any rough edges that can potentially roadblock your research.