High but stable incidence of adult-onset asthma in northern Sweden over the last decades

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.

The incidence of adult-onset asthma in adults has been stable in Sweden over the last 30 years but the relatively high incidence rate in combination with low remission rate in adulthood contributes to the reported increase in asthma prevalence among adultshttps://bit.ly/2QP0AF4

Among respiratory symptoms, wheeze associates most strongly with impaired lung function in adults with asthma: a long-term prospective cohort study

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 FEV1 and FEV1 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 FEV1 on both occasions. Data regarding respiratory symptoms at study entry (recurrent wheeze, dyspnoea, longstanding cough and productive cough) were analysed in relation to FEV1 and annual decline in FEV1, both unadjusted and adjusted for other potentially associated factors by linear regression.

RESULTS

For both sexes recurrent wheeze and dyspnoea were associated with lower FEV1 at study entry and follow-up, while productive cough was associated with lower FEV1 only at follow-up. No associations were found between the type of symptoms and annual decline in FEV1. In adjusted analyses, the association between recurrent wheeze and lower FEV1 both at study entry and follow-up remained significant among women. Also, the association between a higher number of symptoms with lower FEV1 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.

Large underreporting of COPD as cause of death-results from a population-based cohort study

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.

Childhood onset asthma is associated with lower educational level in young adults - A prospective cohort study

BACKGROUND

Asthma is associated with low socioeconomic status among both children and adults, and adolescents with asthma report more school absenteeism than those without. However, it is unclear whether asthma in childhood and adolescence affects socioeconomic status in adulthood.

METHODS

Within the Obstructive Lung disease In Northern Sweden Studies, all children in grade 1 and 2 in three municipalities were invited to a questionnaire survey, 97% participated (n = 3430). They were followed annually until age 19, and thereafter at age 28 years. In this study, participants at ages 8 y, 12 y, 19 y and 28 y (n = 2017) were included. Asthma was categorized into childhood onset (up to age 12 y) and adolescent onset (from 12 to 19 y). Data for assessment of socioeconomic status was collected at 28 y and included educational level, occupation, and occupational exposure to gas, dust and/or fumes (GDF).

RESULTS

Childhood onset asthma was associated with having compulsory school as the highest educational level at age 28 y, also after adjustment for sex, smoking and BMI at age 19 y and socioeconomic factors in childhood (OR 4.84 95%CI 2.01-11.65), and the pattern was the same among men and women. However, we found no significant associations between asthma in childhood or adolescence and socioeconomic groups, occupational groups or occupational exposure to GDF at age 28 y.

CONCLUSIONS

Even though asthma in high-income countries, such as Sweden, is well recognised and treated, this study highlight that childhood onset asthma may have a negative long-term effect with regard to educational level in young adulthood.

Occupation, socioeconomic status and chronic obstructive respiratory diseases - The EpiLung study in Finland, Estonia and Sweden

OBJECTIVE

To study occupational groups and occupational exposure in association with chronic obstructive respiratory diseases.

METHODS

In early 2000s, structured interviews on chronic respiratory diseases and measurements of lung function as well as fractional expiratory nitric oxide (F_ENO) were performed in adult random population samples of Finland, Sweden and Estonia. Occupations were categorized according to three classification systems. Occupational exposure to vapours, gases, dusts and fumes (VGDF) was assessed by a Job-Exposure Matrix (JEM). The data from the countries were combined.

RESULTS

COPD, smoking and occupational exposure were most common in Estonia, while asthma and occupations requiring higher educational levels in Sweden and Finland. In an adjusted regression model, non-manual workers had a three-fold risk for physician-diagnosed asthma (OR 3.18, 95%CI 1.07-9.47) compared to professionals and executives, and the risk was two-fold for healthcare & social workers (OR 2.28, 95%CI 1.14-4.59) compared to administration and sales. An increased risk for physician-diagnosed COPD was seen in manual workers, regardless of classification system, but in contrast to asthma, the risk was mostly explained by smoking and less by occupational exposure to VGDF. For F_ENO, no associations with occupation were observed.

CONCLUSIONS

In this multicenter study from Finland, Sweden and Estonia, COPD was consistently associated with manual occupations with high smoking prevalence, highlighting the need to control for tobacco smoking in studies on occupational associations. In contrast, asthma tended to associate with non-manual occupations requiring higher educational levels. The occupational associations with asthma were not driven by eosinophilic inflammation presented by increased F_ENO.

Level of education and asthma control in adult-onset asthma

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.

Multimorbidity in Finnish and Swedish speaking Finns; association with daily habits and socioeconomic status - Nordic EpiLung cross-sectional study

Multimorbidity is an emerging public health priority. This study aims to assess the role of lifestyle and socioeconomic status in the prevalence of multimorbidity and chronic diseases by using two language groups that are part of the same genetic subgroup but differ by daily habits. We conducted a cross-sectional survey in 2016 with randomly selected population sample with 4173 responders (52.3%) aged 20–69 years in Western Finland. We included 3864 Finnish participants with Swedish (28.1%) or Finnish (71.9%) as a native language. We used a questionnaire to assess participants' chronic diseases and lifestyle. We determined multimorbidity as a disease count ≥ 2.

Finnish speakers were more likely to have a diagnosis of COPD, heart failure, diabetes, reflux disease, chronic kidney failure, and painful conditions than Swedish speakers. The prevalence of multimorbidity was higher for Finnish speakers in the age group of 60–69 years (41.0% vs. 32.0%, p = 0.018) than Swedish speakers. A higher proportion of Finnish speakers smoked, were obese, inactive, and had lower socioeconomic status compared to Swedish speakers. All these factors, in addition to age and female sex, were significant risk factors for multimorbidity. Prevalence of multimorbidity was different in two language groups living in the same area and was associated with differences in lifestyle factors such as smoking, physical inactivity and obesity.

Predictors of electronic cigarette use among Swedish teenagers: a population-based cohort study

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.

Asthma Remission by Age at Diagnosis and Gender in a Population-Based Study

BACKGROUND

Child-onset asthma is known to remit with high probability, but remission in adult-onset asthma is seemingly less frequent. Reports of the association between remission and asthma age of onset up to late adulthood are scarce.

OBJECTIVE

To evaluate the association between asthma remission, age at diagnosis and gender, and assess risk factors of nonremission.

METHODS

In 2016, a random sample of 16,000 subjects aged 20 to 69 years from Helsinki and Western Finland were sent a FinEsS questionnaire. Physician-diagnosed asthma was categorized by age at diagnosis to early- (0-11 years), intermediate- (12-39 years), and late-diagnosed (40-69 years) asthma. Asthma remission was defined by not having had asthma symptoms and not having used asthma medication in the past 12 months.

RESULTS

Totally, 8199 (51.5%) responded, and 879 reported physician-diagnosed asthma. Remission was most common in early-diagnosed (30.2%), followed by intermediate-diagnosed (17.9%), and least common in late-diagnosed asthma (5.0%) (P < .001), and the median times from diagnosis were 27, 18.5, and 10 years, respectively. In males, the corresponding remission rates were 36.7%, 20.0%, and 3.4%, and in females, 20.4%, 16.6%, and 5.9% (gender difference P < .001). In multivariable binary logistic regression analysis, significant risk factors of asthma nonremission were intermediate (odds ratio [OR] = 2.15, 95% confidence interval: 1.37-3.36) and late diagnosis (OR = 11.06, 4.82-25.37) compared with early diagnosis, chronic obstructive pulmonary disease (COPD) (OR = 5.56, 1.26-24.49), allergic rhinitis (OR = 2.28, 1.50-3.46), and family history of asthma (OR = 1.86, 1.22-2.85). Results were similar after excluding COPD.

CONCLUSION

Remission was rare in adults diagnosed with asthma after age 40 years in both genders. Late-diagnosed asthma was the most significant independent risk factor for nonremission.

Dyspnea has an association with lifestyle: differences between Swedish and Finnish speaking persons in Western Finland

Background Difference in dyspnea mMRC ≥2 between Finnish speaking and Swedish-speaking populations in Finland has not been previously studied.

Methods In February 2016, a respiratory questionnaire was sent to 8000 randomly selected subjects aged 20–69 years in western Finland with a response rate of 52.3%. The registered native language of each subject determined whether questionnaire in Finnish or Swedish was applied. Multiple logistic regression was performed to calculate Odds Ratios (OR) with 95% CI for the simultaneous effects of independent variables on dyspnea mMRC ≥2.

Results Of all participants, 2780 (71.9%) were Finnish speakers and 1084 (28.1%) were Swedish speakers. Finnish speakers had a higher prevalence of dyspnea mMRC ≥2 (11.1% vs 6.5% p < 0.001) when compared to Swedish speakers. Finnish speakers smoked more often, had higher BMI, spent less time moving during the day, had more often occupational exposure to vapours, gases, dusts or fumes (VGDF), and had lower socioeconomic status based on occupation. Significant risk factors for dyspnea mMRC ≥2 were COPD (OR = 10.94), BMI >35 (OR = 9.74), asthma (OR = 4.78), female gender (OR = 2.38), older age (OR = 2.20), current smoking (OR = 1.59), and occupational exposure to VGDF (OR = 1.47).

Conclusions Swedish speakers had less dyspnea mMRC ≥2 which is explained by a healthier lifestyle. Smoking, obesity, and occupational exposures should be in focus to improve respiratory health.

The triad of current asthma, rhinitis and eczema is uncommon among adults: Prevalence, sensitization profiles, and risk factors

BACKGROUND

Coexistence of asthma, rhinitis, and eczema has been studied in children, but data are lacking in adults. As new treatments emerge, epidemiological data on the coexistence are needed.

AIMS

To study the prevalence of concomitant asthma, rhinitis and eczema in the general adult population and among those sensitized to aeroallergens, and to study associations between background characteristics and risks of phenotypes of asthma, rhinitis, and eczema.

METHODS

In the West Sweden Asthma Study, phenotypes and sensitization profiles of 1103 randomly selected adults (16-75 years) were assessed. The methods included measures of serum-IgE and structured interviews on asthma, rhinitis, eczema, their associated symptoms, and relevant risk factors.

RESULTS

Among all participants and in those sensitized, 2% and 6% had concomitant asthma, rhinitis, and eczema, respectively, and the condition did not differ by age or sex. Corresponding figures for asthma and rhinitis, but not eczema, was 8% and 19%, respectively. Determinants of coexistence of the three conditions were family history of asthma/allergy, body mass index, and occupational exposure to gas, dust and fumes. Allergic sensitization in those with asthma, rhinitis and eczema was found in 78%, in those with asthma and rhinitis but not eczema in 65%, in those with asthma and eczema but not rhinitis in 40%, while only 5% were sensitized among those having asthma only.

CONCLUSIONS

In the general adult population about 2% have concomitant asthma, rhinitis, and eczema. Of sensitized adults, about 6% has coexistence of the three conditions.

Remission of adult-onset asthma is rare: a 15-year follow-up study

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.

In this 15-year follow-up of a cohort with adult-onset asthma, the remission rate was low, and predictors of remission were higher FEV₁ % predicted and less-severe bronchial hyperreactivity at asthma onsethttps://bit.ly/2FEgoFa

Decreased COPD prevalence in Sweden after decades of decrease in smoking

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.

Low socioeconomic status relates to asthma and wheeze, especially in women

Low socioeconomic status (SES) has been associated with asthma and wheezing. Occupational group, educational level and income are commonly used indicators for SES, but no single indicator can illustrate the entire complexity of SES. The aim was to investigate how different indicators of SES associate with current asthma, allergic and nonallergic, and asthmatic wheeze. In 2016, a random sample of the population aged 20-79 years in Northern Sweden were invited to a postal questionnaire survey, with 58% participating (n=6854). The survey data were linked to the national Integrated Database for Labour Market Research by Statistics Sweden for the previous calendar year, 2015. Included SES indicators were occupation, educational level and income. Manual workers had increased risk for asthmatic wheeze, and manual workers in service for current asthma, especially allergic asthma. Primary school education associated with nonallergic asthma, whereas it tended to be inversely associated with allergic asthma. Low income was associated with asthmatic wheeze. Overall, the findings were more prominent among women, and interaction analyses between sex and income revealed that women, but not men, with low income had an increased risk both for asthmatic wheeze and current asthma, especially allergic asthma. To summarise, the different indicators of socioeconomic status illustrated various aspects of associations between low SES and asthma and wheeze, and the most prominent associations were found among women.