| 1. |
- Emilsson, Össur Ingi, et al.
(author)
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Respiratory symptoms, sleep-disordered breathing and biomarkers in nocturnal gastroesophageal reflux
- 2016
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In: Respiratory Research. - : Springer Science and Business Media LLC. - 1465-993X .- 1465-9921. ; 17
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Journal article (peer-reviewed)abstract
- Background: Nocturnal gastroesophageal reflux (nGER) is associated with respiratory symptoms and sleep-disordered breathing (SDB), but the pathogenesis is unclear. We aimed to investigate the association between nGER and respiratory symptoms, exacerbations of respiratory symptoms, SDB and airway inflammation. Methods: Participants in the European Community Respiratory Health Survey III in Iceland with nGER symptoms (n = 48) and age and gender matched controls (n = 42) were studied by questionnaires, exhaled breath condensate (EBC), particles in exhaled air (PEx) measurements, and a home polygraphic study. An exacerbation of respiratory symptoms was defined as an episode of markedly worse respiratory symptoms in the previous 12 months. Results: Asthma and bronchitis symptoms were more common among nGER subjects than controls (54 % vs 29 %, p = 0.01; and 60 % vs 26 %, p < 0.01, respectively), as were exacerbations of respiratory symptoms (19 % vs 5 %, p = 0.04). Objectively measured snoring was more common among subjects with nGER than controls (snores per hour of sleep, median (IQR): 177 (79-281) vs 67 (32-182), p = 0.004). Pepsin (2.5 ng/ml (0.8-5.8) vs 0.8 ng/ml (0.8-3.6), p = 0.03), substance P (741 pg/ml (626-821) vs 623 pg/ml (562-676), p < 0.001) and 8-isoprostane (3.0 pg/ml (2.7-3.9) vs 2.6 pg/ml (2.2-2.9), p = 0.002) in EBC were higher among nGER subjects than controls. Albumin and surfactant protein A in PEx were lower among nGER subjects. These findings were independent of BMI. Conclusion: In a general population sample, nGER is associated with symptoms of asthma and bronchitis, as well as exacerbations of respiratory symptoms. Also, nGER is associated with increased respiratory effort during sleep. Biomarker measurements in EBC, PEx and serum indicate that micro-aspiration and neurogenic inflammation are plausible mechanisms.
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| 2. |
- Gudbjartsson, Daniel F., et al.
(author)
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Sequence variants affecting eosinophil numbers associate with asthma and myocardial infarction
- 2009
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In: Nature Genetics. - : Springer Science and Business Media LLC. - 1061-4036 .- 1546-1718. ; 41:3, s. 342-347
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Journal article (peer-reviewed)abstract
- Eosinophils are pleiotropic multifunctional leukocytes involved in initiation and propagation of inflammatory responses and thus have important roles in the pathogenesis of inflammatory diseases. Here we describe a genome-wide association scan for sequence variants affecting eosinophil counts in blood of 9,392 Icelanders. The most significant SNPs were studied further in 12,118 Europeans and 5,212 East Asians. SNPs at 2q12 (rs1420101), 2q13 (rs12619285), 3q21 (rs4857855), 5q31 (rs4143832) and 12q24 (rs3184504) reached genome-wide significance (P = 5.3 x 10(-14), 5.4 x 10(-10), 8.6 x 10(-17), 1.2 x 10(-10) and 6.5 x 10(-19), respectively). A SNP at IL1RL1 associated with asthma (P = 5.5 x 10(-12)) in a collection of ten different populations (7,996 cases and 44,890 controls). SNPs at WDR36, IL33 and MYB that showed suggestive association with eosinophil counts were also associated with atopic asthma (P = 4.2 x 10(-6), 2.2 x 10(-5) and 2.4 x 10(-4), respectively). We also found that a nonsynonymous SNP at 12q24, in SH2B3, associated significantly (P = 8.6 x 10(-8)) with myocardial infarction in six different populations (6,650 cases and 40,621 controls).
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| 3. |
- Gunnbjörnsdottir, Maria I, et al.
(author)
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Indoor environment in three North European cities in relationship to atopy and respiratory symptoms
- 2009
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In: Clinical Respiratory Journal. - 1752-6981. ; 3:2, s. 85-94
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Journal article (peer-reviewed)abstract
- In the European Community Respiratory Health Survey (ECRHS) I, the lowest prevalence of asthma and atopy was found in Reykjavik (Iceland) and Tartu (Estonia). The aim of this study was to compare home environments in Reykjavik and Tartu to a town with a higher prevalence of asthma and atopy (Uppsala, Sweden) in an attempt to identify factors in the indoor environment that could explain these differences. A random sample of 129 ECRHS II participants was included in this analysis at each of the three study centres. The subjects answered a questionnaire, blood was analysed for specific immunoglobulin E, a methacholine test was performed and home indoor measurements were taken. The prevalence of atopy was 11.9% in Reykjavik, 35.5% in Uppsala and 28.2% in Tartu (P < 0.04). The level of indoor cat allergen was significantly lower in Reykjavik compared with Uppsala (P = 0.05). No mite allergens were identified in the 41 homes investigated in Reykjavik, while this was the case in 16% and 72% of the households in Uppsala and Tartu, respectively (P = 0.001). A positive association was found between asthma symptoms and cat allergen levels [odds ratio 1.53 (95% confidence interval 1.04-2.24)], while the levels of viable moulds were significantly associated with increased bronchial responsiveness. Indoor exposure to allergens, moulds and bacteria was lower in Reykjavik than in the Swedish and Estonian centres. This finding indicates that the lower prevalence of allergic sensitization in Reykjavik may partly be related to lower indoor allergen exposure. Please cite this paper as: Gunnbjornsdottir MI, NorbAck D, Bjornsson E, Soon A, Jarvis D, Jogi R, Gislason D, Gislason T and Janson C. Indoor environment in three North European cities in relationship to atopy and respiratory symptoms. The Clinical Respiratory Journal 2009; 3: 85-94.
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| 4. |
- Janson, Christer, et al.
(author)
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The effect of infectious burden on the prevalence of atopy and respiratory allergies in Iceland, Estonia, and Sweden
- 2007
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In: Journal of Allergy and Clinical Immunology. - : Elsevier BV. - 0091-6749 .- 1097-6825. ; 120:3, s. 673-679
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Journal article (peer-reviewed)abstract
- Background: Epidemiologic reports on the effect of microbe exposure on the development of atopy and allergic asthma are inconsistent. Objectives: The study investigates the association between serologic markers of infections and occurrence of atopy, allergic asthma, and rhinitis among adults in Iceland, Sweden, and Estonia. Methods: Individuals (n = 1249; mean age, 42 years) from Iceland, Sweden, and Estonia underwent a structured interview and blood sampling. Specific IgE was measured against 4 allergens, and IgG antibodies were measured against Helicobacter pylori, Toxoplasmosis gondii, hepatitis A virus, herpes simplex virus 1, Chlamydia pneumoniae, EBV, and cytomegalovirus. Results: Nonatopic subjects more often had positive serology for Helicobacter pylori, herpes simplex virus 1, Chlamydia pneumoniae, and cytomegalovirus. Having a low number (≤3) of IgG antibodies against the various infectious agents was an independent risk factor for atopy (odds ratio [OR], 1.43; 95% CI, 1.06-1.93), allergic asthma (OR, 1.82; 95% CI, 1.12-2.98), and allergic rhinitis (OR, 1.69; 95% CI, 1.21-2.37). The proportion of atopy that can be explained by a lower number (≤3) of infections was 6.7% in Iceland, 9.2% in Estonia, and 16.4% in Sweden, and 6.7%, 48.2%, and 33.4% for allergic asthma, respectively. Conclusion: Our data are consistent with cumulative protective effect of infections against atopy and respiratory allergies irrespective of route of infection. Clinical implications: The study indicates what microbes or combination of microbes play a role in the complex interplay between hygiene and allergy and may contribute toward the understanding of the allergy epidemic.Background: Epidemiologic reports on the effect of microbe exposure on the development of atopy and allergic asthma are inconsistent. Objectives: The study investigates the association between serologic markers of infections and occurrence of atopy, allergic asthma, and rhinitis among adults in Iceland, Sweden, and Estonia. Methods: Individuals (n = 1249; mean age, 42 years) from Iceland, Sweden, and Estonia underwent a structured interview and blood sampling. Specific IgE was measured against 4 allergens, and IgG antibodies were measured against Helicobacter pylori, Toxoplasmosis gondii, hepatitis A virus, herpes simplex virus 1, Chlamydia pneumoniae, EBV, and cytomegalovirus. Results: Nonatopic subjects more often had positive serology for Helicobacter pylori, herpes simplex virus 1, Chlamydia pneumoniae, and cytomegalovirus. Having a low number (≤3) of IgG antibodies against the various infectious agents was an independent risk factor for atopy (odds ratio [OR], 1.43; 95% CI, 1.06-1.93), allergic asthma (OR, 1.82; 95% CI, 1.12-2.98), and allergic rhinitis (OR, 1.69; 95% CI, 1.21-2.37). The proportion of atopy that can be explained by a lower number (≤3) of infections was 6.7% in Iceland, 9.2% in Estonia, and 16.4% in Sweden, and 6.7%, 48.2%, and 33.4% for allergic asthma, respectively. Conclusion: Our data are consistent with cumulative protective effect of infections against atopy and respiratory allergies irrespective of route of infection. Clinical implications: The study indicates what microbes or combination of microbes play a role in the complex interplay between hygiene and allergy and may contribute toward the understanding of the allergy epidemic.
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| 5. |
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| 6. |
- Olafsdottir, Inga Sif, et al.
(author)
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Gender differences in the association between C-reactive protein, lung function impairment, and COPD
- 2007
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In: International Journal of Chronic Obstructive Pulmonary Disease. - 1176-9106. ; 2:4, s. 635-642
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Journal article (peer-reviewed)abstract
- Individuals with COPD have systemic inflammation that can be assessed by measuring C-reactive protein (CRP). In this paper we evaluated whether CRP is related to COPD, lung function and rate of lung function decline. We included 1237 randomly selected subjects (mean age 42, range 28–56 years) from three centers in the European Community Respiratory Health Survey: Reykjavik, Uppsala and Tartu. CRP was measured at the end of the follow-up (mean 8.3 years) and the values were divided into 4 quartiles. Fifty-three non-asthmatic subjects fulfilled spirometric criteria for COPD (FEV1/FVC < 70%). COPD occurred more often in the 4th CRP quartile (OR (95% CI) 3.21 (1.13–9.08)) after adjustment for age, gender, body weight and smoking. High CRP levels were related to lower FEV1 values in both men (−437 (−596, −279) mL) and women (−144 (−243, −44) mL). The negative association between CRP and FEV1 was significantly larger in men than women (p = 0.04). The decline in FEV1 was larger (16 (5, 27) mL) in men with high CRP levels whereas no significant association between CRP and FEV1 decline was found in women. Higher CRP values are significantly associated with COPD and lower lung function in men and women. In men higher CRP values are related to a larger decline in FEV1.
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| 7. |
- Thjodleifsson, Bjarni, et al.
(author)
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Infections and obesity : A multinational epidemiological study
- 2008
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In: Scandinavian Journal of Infectious Diseases. - : Informa UK Limited. - 0036-5548 .- 1651-1980. ; 40:5, s. 381-386
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Journal article (other academic/artistic)abstract
- Viral infections have been associated with the aetiology of obesity in animal models. This study investigates the association between 7 serological markers of infections and body mass index (BMI) in a population based sample. Individuals (n=985, mean age 42+/-97 (28-55) y, mean BMI 25.594.2) from Iceland, Sweden and Estonia underwent a structured interview and blood sampling. IgG antibodies were measured against Helicobacter pylori and the cagA protein, hepatitis A virus, Toxoplasma gondii, herpes simplex virus 1, Chlamydia pneumoniae, Epstein-Barr virus and cytomegalovirus. High-sensitive C-reactive protein (CRP) was measured as a marker of systemic inflammation. A significant positive association between being overweight (BMI25 kg/m2) and IgG antibodies was found for Helicobacter pylori (OR 1.86, CI 1.34-2.60) and Chlamydia pneumoniae (OR 1.39, CI 1.03-1.88) and combined seropositivity had synergistic effect (OR 2.54 (1.62-3.97)). CRP was positively related to BMI (pB0.0001), whereas no significant association was found between CRP and IgG antibodies against Helicobacter pylori and/or Chlamydia pneumoniae and CRP. The results suggest that infections with Chlamydia pneumoniae and Helicobacter pylori are both significantly and synergistically associated with overweight and this association is not related to indicators of systemic inflammation.
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| 8. |
- Thorhallsdottir, Anna Kristin, et al.
(author)
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Exhaled nitric oxide in a middle-aged Icelandic population cohort.
- 2016
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In: Journal of Breath Research. - : IOP Publishing. - 1752-7155 .- 1752-7163. ; 10:4
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Journal article (peer-reviewed)abstract
- The prevalence of atopy and asthma is relatively low in Iceland. The purpose of this study was to describe exhaled nitric oxide (FeNO) levels in the general population in correlation with demographic characteristics, smoking status, asthma, rhinitis, atopic status and lung function tests. Altogether 403 subjects, from the European Community Respiratory Health Survey (ECRHS) III who answered the main questionnaire and were checked by FeNO measurements, lung function testing, skin prick testing and measurement of total IgE and specific IgE were included. The geometric mean (95% CI) of FeNO was 16.2 ppb (15.2-17.1) and the prevalence of higher FeNO (⩾25 ppb) was 19.5% in the random sample. Subjects with higher FeNO levels were less likely to be current smokers and more likely to have asthma and rhinitis. Having higher FeNO values was also associated with higher total IgE, having specific IgE to at least one allergen and being skin prick test positive. Current smokers had significantly lower levels of FeNO, geometric mean (95% CI) 9.6 ppb (8.4-11.0), than ex-smokers 18.2 ppb (16.6-20.0) and never smokers 17.3 ppb (16.1-18.5). In multivariable models, having asthma (OR (95% CI) 2.10 (1.20-3.67)), having a specific IgE (OR 2.30 (1.25-4.23)) and being skin prick test positive (OR 2.06 (1.18-3.60)) were independently positively associated with a higher FeNO (⩾25) whereas current smoking was independently negatively associated with a higher FeNO (OR 0.19 (0.06-0.63)). Higher levels of FeNO (⩾25 ppb) were found in one out of five Icelanders; FeNO was positively associated with asthma and allergy and negatively with smoking.
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| 9. |
- Abozid, Hazim, et al.
(author)
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Prevalence of chronic cough, its risk factors and population attributable risk in the Burden of Obstructive Lung Disease (BOLD) study : a multinational cross-sectional study
- 2024
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In: eClinicalMedicine. - : Elsevier. - 2589-5370. ; 68
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Journal article (peer-reviewed)abstract
- Background Chronic cough is a common respiratory symptom with an impact on daily activities and quality of life. Global prevalence data are scarce and derive mainly from European and Asian countries and studies with outcomes other than chronic cough. In this study, we aimed to estimate the prevalence of chronic cough across a large number of study sites as well as to identify its main risk factors using a standardised protocol and definition. Methods We analysed cross-sectional data from 33,983 adults (>= 40 years), recruited between Jan 2, 2003 and Dec 26, 2016, in 41 sites (34 countries) from the Burden of Obstructive Lung Disease (BOLD) study. We estimated the prevalence of chronic cough for each site accounting for sampling design. To identify risk factors, we conducted multivariable logistic regression analysis within each site and then pooled estimates using random -effects metaanalysis. We also calculated the population attributable risk (PAR) associated with each of the identifed risk factors. Findings The prevalence of chronic cough varied from 3% in India (rural Pune) to 24% in the United States of America (Lexington,KY). Chronic cough was more common among females, both current and passive smokers, those working in a dusty job, those with a history of tuberculosis, those who were obese, those with a low level of education and those with hypertension or airflow limitation. The most influential risk factors were current smoking and working in a dusty job. Interpretation Our findings suggested that the prevalence of chronic cough varies widely across sites in different world regions. Cigarette smoking and exposure to dust in the workplace are its major risk factors.
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| 10. |
- Amaral, Andre F. S., et al.
(author)
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Chronic airflow obstruction and ambient particulate air pollution
- 2021
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In: Thorax. - : BMJ Publishing Group Ltd. - 0040-6376 .- 1468-3296. ; 76:12, s. 1236-1241
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Journal article (peer-reviewed)abstract
- Smoking is the most well-established cause of chronic airflow obstruction (CAO) but particulate air pollution and poverty have also been implicated. We regressed sex-specific prevalence of CAO from 41 Burden of Obstructive Lung Disease study sites against smoking prevalence from the same study, the gross national income per capita and the local annual mean level of ambient particulate matter (PM2.5) using negative binomial regression. The prevalence of CAO was not independently associated with PM2.5 but was strongly associated with smoking and was also associated with poverty. Strengthening tobacco control and improved understanding of the link between CAO and poverty should be prioritised.
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