| 51. |
- Backman, Helena, et al.
(författare)
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Level of Education Modifies Asthma Mortality in Norway and Sweden. The Nordic EpiLung Study
- 2024
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Ingår i: JOURNAL OF ASTHMA AND ALLERGY. - : Dove Medical Press. - 1178-6965. ; 17, s. 209-218
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Tidskriftsartikel (refereegranskat)abstract
- Background and Aim: The relationship between socioeconomic status (SES), asthma and mortality is complex and multifaceted, and it is not established if educational level modifies the association between asthma and mortality. The aim was to study the association between asthma and mortality in Sweden and Norway and to what extent educational level modifies this association. Participants and Methods: Within the Nordic EpiLung Study, >56,000 individuals aged 30-69 years participated in population -based surveys on asthma and associated risk factors in Sweden and Norway during 2005-2007. Data on educational level and 10-year all -cause mortality were linked by national authorities. The fraction of mortality risk attributable to asthma was calculated, and Cox regression was used to estimate hazard ratios (HR) and 95% confidence intervals (95% CI) for mortality related to asthma, stratified by educational level. Results: In total, 5.5% of all deaths was attributed to asthma. When adjusted for potential confounders, the HR for mortality related to asthma was 1.71 (95% CI 1.52-1.93). Those with primary level of education had higher hazard of all -cause death related to asthma than those with tertiary level (HR 1.80, 95% CI 1.48-2.18, vs HR 1.39, 95% CI 0.99-1.95). Conclusion: Asthma was associated with an overall 71% increased all -cause mortality and 5.5% of deaths can be attributed to asthma. Educational levels modified the risk of mortality associated with asthma, with the highest risk among those with primary education.
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| 52. |
- 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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| 53. |
- Backman, Helena, et al.
(författare)
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Lung function trajectories and associated mortality among adults with and without airway obstruction
- 2023
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Ingår i: American Journal of Respiratory and Critical Care Medicine. - : American Thoracic Society. - 1073-449X .- 1535-4970. ; 208:10, s. 1063-1074
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Tidskriftsartikel (refereegranskat)abstract
- 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.
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| 54. |
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| 55. |
- Backman, Helena, et al.
(författare)
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Prevalence trends in respiratory symptoms and asthma in relation to smoking : two cross-sectional studies ten years apart among adults in northern Sweden
- 2014
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Ingår i: World Allergy Organization Journal. - : BioMed Central (BMC). - 1939-4551. ; 7:1, s. 1-
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Smoking 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.METHODS: Data 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.RESULTS: The 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%).CONCLUSIONS: In 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.
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| 56. |
- Backman, Helena, 1979-, et al.
(författare)
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Reference values for spirometry - report from the Obstructive Lung Disease in Northern Sweden studies.
- 2015
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Ingår i: European clinical respiratory journal. - : Informa UK Limited. - 2001-8525. ; 2, s. Article number 26375-
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Tidskriftsartikel (refereegranskat)abstract
- Abnormal lung function is commonly identified by comparing observed spirometric values to corresponding reference values. It is recommended that such reference values for spirometry are evaluated and updated frequently. The aim of this study was to estimate new reference values for Swedish adults by fitting a multivariable regression model to a healthy non-smoking general population sample from northern Sweden. Further aims were to evaluate the external validity of the obtained reference values on a contemporary sample from south-western Sweden, and to compare them to the Global Lung Function Initiative (GLI) reference values.
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| 57. |
- 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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| 58. |
- Backman, Helena, et al.
(författare)
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Restrictive spirometric pattern in the general adult population: Methods of defining the condition and consequences on prevalence
- 2016
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Ingår i: Respiratory Medicine. - : Elsevier BV. - 0954-6111 .- 1532-3064. ; 120, s. 116-123
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Tidskriftsartikel (refereegranskat)abstract
- Background Attempts have been made to use dynamic spirometry to define restrictive lung function, but the definition of a restrictive spirometric pattern (RSP) varies between studies such as BOLD and NHANES. The aim of this study was to estimate the prevalence and risk factors of RSP among adults in northern Sweden based on different definitions. Methods In 2008–2009 a general population sample aged 21–86y within the obstructive lung disease in northern Sweden (OLIN) studies was examined by structured interview and spirometry, and 726 subjects participated (71% of invited). The prevalence of RSP was calculated according to three different definitions based on pre-as well as post-bronchodilator spirometry: 1) FVC<80% & FEV1/FVC>0.7 2) FVC<80% & FEV1/FVC>LLN 3) FVCLLN Results The three definitions yielded RSP prevalence estimates of 10.5%, 11.2% and 9.4% respectively, when based on pre-bronchodilator values. The prevalence was lower when based on post-bronchodilator values, i.e. 7.3%, 7.9% and 6.6%. According to definition 1 and 2, the RSP prevalence increased by age, but not according to definition 3. The overlap between the definitions was substantial. When corrected for confounding factors, manual work in industry and diabetes with obesity were independently associated with an increased risk for RSP regardless of definition. Conclusions The prevalence of RSP was 7–11%. The prevalence estimates differed more depending on the choice of pre- compared to post-bronchodilator values than on the choice of RSP definition. RSP was, regardless of definition, independently associated with manual work in industry and diabetes with obesity. © 2016 The Authors
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| 59. |
- 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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| 60. |
- Backman, Helena, et al.
(författare)
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Severe asthma : A population study perspective
- 2019
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Ingår i: Clinical and Experimental Allergy. - : John Wiley & Sons. - 0954-7894 .- 1365-2222. ; 49:6, s. 819-828
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Tidskriftsartikel (refereegranskat)abstract
- BackgroundSevere 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.ObjectiveTo describe characteristics and estimate the prevalence of severe asthma in a large adult population‐based asthma cohort followed for 10‐28 years.MethodsN=1006 subjects with asthma participated in a follow‐up during 2012‐14, when 830 (mean age 59y, 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 Program (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.ResultsThe 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, >40% had uncontrolled 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 relevanceSevere 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.
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