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- Almqvist, Linnea, 1987-
(författare)
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Asthma epidemiology : prognosis of asthma with onset in childhood and in adulthood
- 2024
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Aim: to update the knowledge on the epidemiology of asthma with onset in childhood and adulthood as well as examine the importance of risk factors in early childhood and clinical characteristics on the incidence and prognosis of asthma.Methods: The thesis is based on the epidemiological research program Obstructive Lung Disease in Northern Sweden (OLIN) studies. Pediatric cohort: recruited in 1996 (age 8y, n=3430, 97% of invited) and followed annually by questionnaire about asthma, allergy and risk factors until 19y and a postal questionnaire at 28y. Clinical examinations included skin prick tests (SPT at 8, 12 and 19y) and spirometry (19y). Adult cohort: 309 adults (age 20–60y) with asthma onset in the last 12 months were recruited 1995-99 and re-examined in 2012-14 (n=205). Structured interviews, spirometry and SPT were performed at recruitment and follow-up and bronchial hyperreactivity (BHR) at recruitment.Results: The asthma incidence rate was 10-13/1000/year in childhood and adolescence and 6/1000/year in young adulthood. Several risk factors in early life were associated with asthma onset in childhood, adolescence and young adulthood, e.g. family history of asthma, <3 months breastfeeding, rhinoconjunctivitis and positive SPT at 8y, while low birthweight, maternal smoking during pregnancy, severe respiratory infections and eczema were associated with onset in childhood and adolescence. Among those with asthma at 8y, 62% still had asthma at 28y and this was associated with positive SPT, rhinoconjunctivitis, severe respiratory infection in childhood, and bronchial hyperreactivity (BHR) in adolescence. Coexistence of asthma, rhinitis and eczema increased by age, especially among those with a positive SPT. However, having all three conditions was uncommon. In the 15y follow-up adult onset asthma, 89% had persistent asthma. Better lung function at recruitment and less severe BHR was associated with remission. Remission rate of adult onset asthma was <1% per year.Conclusion: The incidence of asthma was high during childhood and adolescence and then decreased in young adulthood. Factors in early life that were associated with incident asthma during childhood were still associated with the incidence in adult age. Among those with asthma onset by 8 years, 62%, still had asthma as young adults. The coexistence of asthma, rhinitis and eczema varied from 8 to 28y without following a specific pattern, only a small proportion reported having all three conditions. Remission of adult onset asthma was rare.
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| 2. |
- Almqvist, Linnéa, et al.
(författare)
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Clinical outcome of adult onset asthma in a 15 year follow-up
- 2020
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Ingår i: European Respiratory Journal. - : European Respiratory Society (ERS). - 0903-1936 .- 1399-3003. ; 56:Suppl 64
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Background: Adult onset asthma is poorly studied and there are few long-term clinical follow-up studies.Aim: To study clinical characteristics of adult onset asthma in a 15-year follow-up.Method: Within the Obstructive Lung Disease in Northern Sweden (OLIN) studies, a cohort of n=309 subjects with adult onset asthma (aged 20-60 years) was recruited during 1995-99. The cohort was followed up in 2012-14 (n=205). Structured interviews and clinical examinations including spirometry were performed at both recruitment and follow-up. Skin prick tests were performed at recruitment and blood samples for cell counts and IgE at the follow-up. Asthma control was classified according to GINA 2006.Results: At follow-up n=182 (89%) still had asthma, while n=23 (11%) were in remission. Among individuals with persistent asthma, mean pre-bronchodilator FEV1 percent of predicted was 89.0 at follow-up, similar as recruitment 88.3. At recruitment 16.5% were smokers, and of these, 86.7% had quit smoking at follow-up. At follow-up, 39% had blood neutrophils ≥4.0x109/L, 23% had blood eosinophils ≥0.3x109/L, and 28% had specific IgE>0.35 IU/ml to any airborne allergen. Any respiratory symptoms were reported by 90% and 31% used medium or high dose inhaled corticosteroids (ICS), 20% low dose ICS whereas 20% had no treatment. 55% had controlled asthma, 32% partly controlled and 13% uncontrolled asthma.Conclusion: In this 15-year follow-up of adult onset asthma, the majority had persistent asthma. Smoking and high proportion using ICS may contribute to the stable lung function. Still, it should be noted that merely around every other had well controlled asthma.
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| 4. |
- Backman, Helena, 1979-
(författare)
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Lung function and prevalence trends in asthma and COPD
- 2016
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Background: Asthma and chronic obstructive pulmonary disease (COPD) are common obstructive airway diseases with a substantial burden in terms of morbidity, mortality and costs. Smoking is the single most important risk factor for COPD, and is associated with incident asthma. It is important to know if the prevalence of asthma and COPD is increasing or decreasing in the population in order to effectively allocate health care resources. The definitions of these diseases have varied over time which makes it difficult to measure changes in prevalence. The preferred method is to estimate the prevalence with the same procedures and definitions based on cross-sectional population samples with identical age distributions in the same geographical area at different time points. Measurements of lung function (spirometry) are required to diagnose COPD, and spirometry is used to evaluate disease severity and progress of both asthma and COPD, where observed values are compared to reference values. The most commonly used reference values in Sweden are published during the mid 1980s, and there are few evaluations of how appropriate they are today based on Swedish population samples. The aim of the thesis was to estimate trends in the prevalence of asthma and COPD in relation to smoking habits, and to evaluate and estimate reference values for spirometry.Methods: The project was based on population-based samples of adults from the Obstructive Lung Disease in Northern Sweden (OLIN) studies. Postal questionnaires were sent to large cohorts, recruited in 1992 (n=4851, 20-69 years), 1996 (n=7420, 20-74 years) and 2006 (n=6165, 20-69 years), respectively. The questionnaire included questions on respiratory symptoms and diseases, their comorbidities and several possible risk factors including smoking habits. Structured interviews and spirometry were performed in random samples of the responders to the 1992 and 2006 surveys, of which n=660 (in 1994) and n=623 (in 2009) were within identical age-spans (23-72 years). The trend in asthma prevalence was estimated by comparing the postal questionnaire surveys in 1996 and 2006, and the trend in COPD prevalence was estimated by comparing the samples participating in dynamic spirometry in 1994 and 2009, respectively. The prevalence of COPD was estimated based on two different definitions of COPD. Commonly used reference values for spirometry were evaluated based on randomly sampled healthy non-smokers defined in clinical examinations of participants in the 2006 postal questionnaire (n=501). The main focus of the evaluation was the global lung function initiative (GLI) reference values published in 2012, for which Z-scores and percent of predicted values were analysed. New sex-specific reference values for spirometry were estimated by linear regression, with age and height as predictors. These new OLIN reference values were also evaluated on a sample of healthy non-smokers identified in the population-based West Sweden Asthma Study.Results: Although the prevalence of smoking decreased from 27.4% to 19.1%, p<0.001, between 1996 and 2006, the prevalence of physician-diagnosed asthma increased from 9.4% to 11.6%, p<0.001. The prevalence of symptoms common in asthma such as recurrent wheeze did not change significantly between the surveys or tended to decrease, while bronchitis symptoms such as cough and sputum production decreased significantly. The evaluation of the GLI reference values showed that the predicted values were significantly lower compared to the observed values in Norrbotten, which makes the percent of predicted too high. This was especially true for FVC percent predicted with a mean of 106%. In general, the deviations were more pronounced among women. New OLIN reference values valid for the Norrbotten sample were modelled and showed a high external validity when applied on the sample from western Sweden. The prevalence of moderate to severe COPD decreased substantially over the 15-year period between 1994 and 2009, regardless of definition.Conclusions: In parallel with substantially decreased smoking habits in the population between 1996 and 2006, the prevalence of several airway symptoms decreased while the prevalence of physician-diagnosed asthma increased. These results suggest increased diagnostic activity for asthma, but may also suggest that the asthma prevalence has continued to increase. In contrast to asthma, the prevalence of COPD tended to decrease and moderate to severe COPD decreased substantially. The continuous decrease in smoking in Sweden during several decades prior to the study period is most likely contributing to these results. The evaluation of reference values showed that the GLI reference values were lower than the observed spirometric values in the population, especially for women, why the new up-to date reference values may be of importance for disease evaluation in epidemiology and in the health care as well.
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| 5. |
- Backman, Helena, et al.
(författare)
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Respiratory symptoms as risk factors for mortality – the Nordic EpiLung Study
- 2020
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Ingår i: European Respiratory Journal. - : European Respiratory Society (ERS). - 0903-1936 .- 1399-3003. ; 56:Suppl 64
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Background: Little is known on associations between respiratory symptoms and mortality.Aim: To study whether respiratory symptoms are risk factors for all-cause, respiratory, cardiovascular (CV), and cancer mortality in Sweden and Norway.Methods: In 1995-1997, population samples (20-69y) were surveyed about respiratory symptoms, and n=7,104 (85.3% of invited, median age 45y) and n=54,240 (70.1%, 44y) participated within the OLIN Studies in Northern Sweden and the HUNT Study in Norway. Mortality was studied until December 31st 2015. Hazard ratios (HR) for associations between respiratory symptoms and mortality were estimated by Cox regression models adjusted for age, sex, educational level, and smoking habits.Results: The cumulative 20-year mortality was 14.5% in OLIN and 12.6% in HUNT. Dyspnea (mMRC grade≥2) (HR 1.9, 95%CI 1.6-2.2 in OLIN and 1.6, 1.5-1.7 in HUNT), chronic productive cough (1.5, 1.3-1.8 and 1.5, 1.3-1.6), and wheeze (1.3, 1.1-1.5 and 1.3, 1.2-1.4) were associated with increased risk of all-cause mortality. Women reported dyspnea and wheeze more frequently than men in both countries, but the association with mortality was similar in both sexes. Causes of death were studied in OLIN, where dyspnea associated with increased risk of respiratory (3.6, 2.1-6.1), CV (2.1, 1.6-2.7), and cancer (1.3, 1.0-1.8) mortality. Chronic productive cough was associated with increased risk of respiratory (2.4, 1.3-4.3) and cancer (1.6, 1.2-2.2) mortality, while wheeze was associated with increased risk of respiratory (3.5, 2.1-5.7) and CV (1.3, 1.0-1.6) mortality.Conclusions: Common respiratory symptoms were similarly associated with increased risk of mortality in adults in Sweden and Norway.
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| 6. |
- Backman, Helena, et al.
(författare)
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Risk factors for severe asthma among adults with asthma
- 2020
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Ingår i: European Respiratory Journal. - : European Respiratory Society (ERS). - 0903-1936 .- 1399-3003. ; 56:Suppl 64
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Background: Severe asthma is a considerable challenge for patients, health care professionals and society, but there are few long-term studies on risk factors for severe asthma.Aim: To identify baseline risk factors of severe asthma in a longitudinal adult asthma cohort study.Methods: An adult asthma cohort was identified in 1986-2001 by clinical examinations of population samples within the OLIN studies in northern Sweden. The examinations included structured interviews, spirometry with reversibility testing, skin prick testing and metacholine challenge. The cohort was followed up in 2012-2014 when n=1006 participated (mean age 59y). Adjusted Risk Ratios (RR) for baseline factors as risk factors for GINA defined severe asthma (SA) at follow-up (n=51) were estimated by Poisson regression.Results: Older age, impaired lung function, increased reversibility and hyperreactivity, asthmatic wheeze, persistent wheeze, nighttime awakenings due to respiratory symptoms, and dyspnea were significant baseline risk factors for SA. Allergic sensitization, smoking, occupational groups or BMI did not predict SA. When adjusted for age, sex and smoking, post-bronchodilator FEV1/FVC<0.7, both present at baseline (RR 4.2, 95%CI 1.8-9.9) and developed during follow-up (2.9, 1.6-5.3), increased the risk. Also FEV1<80% at baseline associated with SA (2.9, 1.6-5.2). Triggers for respiratory symptoms at baseline such as tobacco smoke (2.1, 1.2-3.7) and physical activity (3.5, 1.5-81) associated with SA at follow-up, while pollen and furry animals did not.Conclusion: Among adults with asthma, impaired lung function, wheeze, dyspnea and nighttime awakenings due to respiratory symptoms are important long-term risk factors for severe asthma.
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| 8. |
- Bunne, Joakim, 1987-
(författare)
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Allergic sensitization among schoolchildren in northern Sweden : time trends, risk factors and relation to asthma, allergic rhinitis and lung function.
- 2024
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Background: Asthma and allergic rhinitis are common chronic diseases of childhood.Their prevalence has increased globally in the 20th century, with regionally diverging trends in recent years. Allergic sensitization (AS) is strongly associated with asthma and allergic rhinitis (AR), with similar trends over time and uncertainty of development in recent years. AS increases in childhood until young adulthood. Risk factors for AS are not as well characterized as for asthma and AR, and important aspects of the relation between AS and disease are not known. This includes why some sensitized children do not develop disease and how common this is in a longitudinal perspective. While many studies have assessed AS in the first years of life, fewer have focused on school age, and none have focused on the effect of age at onset of AS. Further, the association between AS and lung function is unknown.Aims: To assess time trends in prevalence, incidence and factors associated with AS in schoolchildren. Further, to assess the association between AS and asthma, allergic rhinitis and lung function, with special interest in age at onset of sensitization.Methods: Children in grades 1 and 2 (median age 8 years) in two municipalities in northern Sweden were invited to a questionnaire study of allergic diseases and skin prick tests to common aeroallergens in 1996. The cohort was reassessed at 12 and at 19 years also including spirometry. Identical methods were used to recruit a second and third cohort in 2006 and 2017.Results: The prevalence of AS at 8 years was 21% (1996), 30% (2006) and 30% (2017). Patterns of sensitization and risk factors for sensitization were similar. In the second cohort, the incidence between 8-12 years of 18% and prevalence of 41% at 12 years were higher than in the first cohort. Compared with later onset, sensitization ≤8 years was more strongly associated with asthma and allergic rhinitis at 19 years. AS was not independently associated with lung function at 19 years.Conclusions: In northern Sweden, the increase in allergic sensitization at age 8 years between 1996 and 2006 has halted in recent years. The increase between the first two cohorts was seen also at age 12 years. Age at onset of allergic sensitization impacts development of asthma and allergic rhinitis until 19 years. Despite an association with asthma, sensitization does not affect lung function at 19 years.
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| 9. |
- Hedman, Linnea, 1979-, et al.
(författare)
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Asthma do not counteract smoking initiation
- 2020
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Ingår i: European Respiratory Journal. - : European Respiratory Society. - 0903-1936 .- 1399-3003. ; 56
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
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| 10. |
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