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Biomedical subjects

Vibeke Backer

Publications and source records attributed to Vibeke Backer.

At least 19 recordsLinked to original sources
PubMed2007

Association of airway hyperresponsiveness with reduced quality of life in patients with moderate to severe asthma.

BACKGROUND: Airway hyperresponsiveness (AHR) is an indicator of poor asthma control. Asthma patients with AHR to methacholine have been shown to have a poorer quality of life compared with asthma patients without AHR, but it is not clear to what degree this is a result of more severe disease in patients with AHR. OBJECTIVES: To describe the relationship between AHR and quality of life in asthma patients and to determine the impact of the severity of asthma on this relationship. METHODS: Data from 691 asthma patients were analyzed to describe the relationship between the impact of AHR to methacholine (cumulative dose of methacholine required to provoke a 20% decrease in forced expiratory volume in 1 second, < or = 8 micromol) on quality of life (measured by the Asthma Quality of Life Questionnaire) of asthma patients in relation to the severity of asthma (according to the Global Initiative for Asthma guidelines). RESULTS: Asthma patients with AHR had more severe asthma and a poorer quality of life compared with asthma patients without AHR. Furthermore, the quality of life decreased with increasing severity of asthma. However, regression analysis showed an independent association between both the presence of AHR and the severity of asthma and quality of life, as well as an interaction between the effects of these 2 factors. Finally, subgroup analysis showed that the impact of AHR on the quality of life was only clinically significant in moderate to severe asthma but not in mild asthma. CONCLUSIONS: AHR is associated with a negative impact on the quality of life of asthma patients that is partly independent of the severity of asthma.

Asthma↗
PubMed2006

Associations of a novel IL4RA polymorphism, Ala57Thr, in Greenlander Inuit.

BACKGROUND: A novel IL4RA polymorphism, Ala57Thr, was identified in Greenlander Inuit. OBJECTIVE: We sought to determine whether the novel Thr57 allele is population specific and to assess the associations of Ala57Thr and Ile50Val with atopy in 2 Inuit populations. METHODS: Ala57Thr and Ile50Val were genotyped in 651 Inuit living in Denmark, 1295 Inuit living in Greenland, and 1329 individuals from 7 populations from widely differing global locations. In Inuit the polymorphisms were evaluated for associations with atopy, rhinitis, asthma, and pulmonary function. RESULTS: Thr57 was in linkage disequilibrium with Ile50 (D' = 1, r(2) = 0.13) and was common (33%) in the Inuit but rare (<0.6%) in all other populations. In Inuit living in Denmark, the Thr57 allele (in a dose-dependent manner) and the Ile50/Thr57 haplotype were associated with lower risk of atopy (P(linear) = .003 and P = .034, respectively), with similar trends observed for atopic rhinitis and atopic asthma. In Inuit living in Greenland, Thr57 was not associated with atopy or atopic diseases, but Ile50 was weakly associated with lower risk of atopy. CONCLUSION: The novel IL4RA Ala57Thr was common in and population specific to Greenlander Inuit, with Thr57 associated with a lower risk of atopy in those living in Denmark. Hence a full investigation of genotype-phenotype relationships in a given population can only be achieved if each gene is screened for novel polymorphisms in that population. CLINICAL IMPLICATIONS: Clinical risk attributable to variations in a gene in an ethnic group requires that all variations of the gene are known for that group.

Adult↗
PubMed2006

Genetic and environmental contributions to hay fever among young adult twins.

BACKGROUND: The susceptibility to develop hay fever is putatively the result both of genetic and environmental causes. We estimated the significance and magnitude of genetic and environmental contributions to hay fever among young adult twins. METHODS: From the birth cohorts 1953-82 of The Danish Twin Registry 11,750 twin pairs were identified through a nationwide questionnaire survey. Subjects were regarded hay fever cases when responding affirmatively to the question 'Do you have, or have you ever had hay fever?' Latent factor models of genetic and environmental effects were fitted to the observed data using maximum likelihood methods. RESULTS: The overall cumulative prevalence of hay fever was 12.6%. Identical twins were significantly more likely to be concordant for hay fever than were fraternal twins (P<0.001). Additive genetic effects accounted for 71% and non-shared environmental effects accounted for 29% of the individual susceptibility to hay fever. The same genes contributed to the susceptibility to hay fever both in males and in females. In families with asthma, the susceptibility to develop hay fever was, in addition to genes, to a great extent ascribable to family environment, whereas the aetiology of 'sporadic' hay fever was mainly genetic. CONCLUSIONS: The susceptibility to develop hay fever is attributable to major genetic influences. However, effects of family environment and upbringing are also of importance in families where asthma is present. These results indicate that different sub-forms of hay fever may have different aetiologies.

Adolescent↗
PubMed2006

Quality of care in patients with asthma and rhinitis treated by respiratory specialists and primary care physicians: a 3-year randomized and prospective follow-up study.

BACKGROUND: Previous studies evaluating asthma care provided by primary care providers and respiratory specialists (RSs) are limited by short observation periods and nonrandomized designs. OBJECTIVE: To evaluate long-term outcomes in patients with asthma and rhinitis randomly selected to be cared for by RSs or primary care specialists. METHODS: In a randomized, 3-year, longitudinal study, 472 patients with asthma and allergic rhinitis were cared for by RSs or primary care physicians. Outcome measures, including disease severity, lung function, medication use, compliance, and self-management knowledge, were compared between groups. RESULTS: Compared with patients followed up by primary care providers, those in the RS group had reduced asthma severity (P = .046), significantly fewer days with asthma symptoms (P < .01), and improved asthma self-management knowledge (P < .01). At baseline, most patients were undertreated. This value was significantly reduced from 74% to 37% in the RS group and from 71% to 57% in the primary care physician group. We found odds ratios of 8.5 (95% confidence interval, 2-43; P < .01) for worsening of asthma and 0.3 (95% confidence interval, 0.1-0.9; P = .04) for asthma improvement when followed up by primary care physicians, which indicates that primary care follow-up increases the risk of worsening of asthma and decreases the chance of improving. Similar results were observed in patients with allergic rhinitis, although the findings were less pronounced. CONCLUSION: Treatment and follow-up by an RS ensured better quality of care in patients with asthma and rhinitis.

Adolescent↗
PubMed2006

Skin test reactivity among Danish children measured 15 years apart.

BACKGROUND: Knowledge of secular trends in the prevalence of allergy among children stems in large part from questionnaire surveys, whereas repeated cross-sectional studies using objective markers of atopic sensitization are sparse. OBJECTIVES: To investigate whether the prevalence of skin prick test (SPT) positivity in Danish children has changed from 1986 to 2001. METHODS: Serial cross-sectional studies of two different random population samples of children aged 7 to 17 years of age, living in urban Copenhagen, Denmark, were performed 15 years apart. The first cohort was investigated in 1986 (n = 527) and the second in 2001 (n = 480). Skin test reactivity to nine common aeroallergens was measured at both occasions. RESULTS: The prevalence of positive SPT to at least one allergen decreased from 24.1% in 1986 to 18.9% in 2001, (p = 0.05). We found a declining prevalence of sensitization to most allergens tested, statistically significant; however, only for mugwort and Alternaria iridis. Among subjects, who were sensitized to only one allergen, we found significantly fewer individuals with reactions to D. pteronyssinus and mugwort. CONCLUSIONS: The prevalence of atopic sensitization as judged by SPT positivity has decreased or remained unchanged among Danish children during the 15-year period from 1986 to 2001. The increase in prevalence of allergic disease often reported in comparable studies using questionnaires as sole diagnostic criterion could not be reproduced in this study where objective markers of allergic sensitization were included in the design.

Adolescent↗
PubMed2006

The patient's perspective: adherence or non-adherence to asthma controller therapy?

STUDY OBJECTIVE: Adherence with controller therapy poses a major challenge to the effective management of persistent asthma. The aim of this study was to explore the patient-related aspects of adherence among adult asthmatics. DESIGN AND PARTICIPANTS: The participants (n = 509 adult asthmatics), recruited from all parts of Denmark, answered the questionnaire concerning asthma knowledge, attitudes, adherence, and treatment through the Internet. RESULTS: A total of 67% of the patients were prescribed inhaled corticosteroids (ICS). However, according to Global Initiative for Asthma (GINA)-guidelines' symptom severity classification, 85% should have been on ICS. Accidental and intentional non-adherence with ICS at least twice a week was reported by 27% and 24%, respectively. In case of deterioration, 60% of the patients preferred to take more reliever medication, instead of increasing the ICS dose. Having a fixed daily routine with regard to medication and following the advice given by their doctor were the main reasons for adherence, whereas lack of perceived symptoms was the main reason for non-adherence. Non-adherence was associated with increasing disagreement with the statements that controller therapy is effective (p < 0.04), as well as an essential part of asthma therapy (p < 0.002). CONCLUSIONS: Both accidental and intentional non-adherence with controller therapy is common among adult asthmatics. The reasons for suboptimal adherence seem to be accessible through education of both patients and caregivers.

Administration, Inhalation↗
PubMed2006

Risk factors for onset of asthma: a 12-year prospective follow-up study.

BACKGROUND: Asthma development and prognosis have been studied extensively in at-risk populations, but knowledge of the natural history of asthma in the general population is limited. OBJECTIVE: To describe the incidence and remission of asthma and its predictors, data from a 12-year follow-up study of a random population sample (n = 291; age range, 7 to 17 years) at enrollment, were analyzed. METHODS: The sample was examined in 1986 and in 1998. A case history, including data on asthma, allergic diseases, and lifestyle factors, was obtained by questionnaire and interview. Airway hyperresponsiveness (AHR) to histamine, lung function, and skin-prick test reactivity to a standard panel of 10 aeroallergens were measured. RESULTS: The point prevalence of asthma increased from 4.1% at the first survey to 11.7% at follow-up, at which point 19.6% of the sample had ever experienced asthma symptoms. Of the subjects with ever-asthma, 40% had remitted at follow-up. Asthma developed in 45 subjects (16.1%) during the follow-up period, which was predicted by the following factors: wheezing in childhood (odds ratio [OR], 3.61; 95% confidence interval [CI], 1.34 to 9.75), AHR (OR, 4.94; 95% CI, 2.42 to 10.08), allergic sensitization to house dust mites (OR, 3.23; 95% CI, 1.00 to 10.40), and dermatitis (OR, 2.94; 95% CI, 1.22 to 7.11). The simultaneous presence of more than one of these risk factors was associated with a high probability of developing asthma at follow-up (61.5%). In subjects without any risk factors, such as AHR, allergic sensitization, rhinitis, dermatitis or wheezing in childhood; paternal/maternal allergy, or asthma, asthma developed in only 4% during follow-up. CONCLUSION: The presence of AHR and concomitant atopic manifestations in childhood increase the risk of developing asthma in adulthood, and should be recognized as markers of prognostic significance, whereas the absence of these manifestations predicts a very low risk of future asthma.

Adolescent↗
PubMed2005

Unawareness and undertreatment of asthma and allergic rhinitis in a general population.

UNLABELLED: The aim of this study was to determine the extent of unawareness and undertreatment of asthma and allergic rhinitis in an adolescent and adult population in Copenhagen, Denmark. METHODS: Patients with asthma and rhinitis were recruited by a standardised asthma and rhinitis screening questionnaire. Out of a random sample of 10,877 subjects aged 14-44 years, 1149 subjects were treated or reported symptoms of asthma or rhinitis and agreed to participate. Those subjects were assessed on history, lung function tests, and skin prick tests. Disease severity and optimal treatment were decided according to the GINA and ARIA guidelines. RESULTS: A total of 726 participants suffered from asthma and/or allergic rhinitis. Concomitant upper and lower airways disease was found in 47%. Seventy-five per cent were allergic and 44% with a known allergy had been tested previously. Asthma was undiagnosed and untreated in 50% of all the asthmatics. According to the guideline recommendation, 76% of asthmatics were undertreated. Rhinitis was undiagnosed in 32% of patients and 83% with moderate to severe rhinitis were undertreated. Patient knowledge about self-care and education was low. CONCLUSIONS: In this population a large proportion of patients were unaware of having asthma or rhinitis. The pharmaceutical treatment and management practice were inadequate. Our study emphasises the need for additional intervention.

Adolescent↗
PubMed2005

Chronic mucus hypersecretion: a marker of asthma in young adults?

OBJECTIVE: To investigate if chronic mucus hypersecretion (CMH) can be used as a marker of asthma in young adults. STUDY DESIGN AND SETTING: Cross-sectional study of a population sample of young Danish adults (n=624, 279 males), aged 19-29 years. Case history, including tobacco exposure and respiratory symptoms, was obtained by questionnaire. Pulmonary function, histamine responsiveness, bronchodilator reversibility, skin test reactivity, and leukocyte count were measured using standard techniques. RESULTS: The overall prevalence of CMH was 7.7%, 8.4% in females and 6.9% in males, respectively, of whom more than 70% were current smokers. The presence of CMH was significantly associated with self-reported asthma, dyspnea at exertion, number of pack-years, lower FEV1/FVC ratio, and lower BMI. However, no significant association was found between CMH and the following asthma-related factors: airway responsiveness to inhaled histamine, bronchodilator reversibility, self-reported rhinitis or eczema, atopy, FEV1 (%pred), and B-eosinophil count. CONCLUSIONS: CMH is a common finding in young adults, primarily in smokers. CMH was related to respiratory symptoms suggesting asthma, but no significant association was observed between CMH and objective signs of asthmatic airway lability. The present findings therefore may suggest that CMH is likely to be an early marker of smoking-related lung disease in young adults, instead of a marker of reversible obstructive lung disease, which may have important implications for the approach to young people presenting with respiratory symptoms suggesting asthma.

Adult↗
PubMed2005

Association between asthma-related phenotypes and the CC16 A38G polymorphism in an unselected population of young adult Danes.

The gene for Clara cell 16-kDa (CC16) protein is a promising candidate for asthma susceptibility. The CC16 38A allele has been associated with decreased CC16 plasma levels and increased incidence of asthma in Australian children. To date these results have not been replicated in adults. Therefore, potential links between CC16 A38G, asthma and atopy were investigated in an unselected population of young adult Danes. Four hundred sixty-four Danes, aged 19-29 years, from Copenhagen participated in an asthma and allergy phenotype-genotype study. Genotyping was done by Sau96I restriction digestion of PCR products spanning the A38G polymorphism. Potential A38G genotype and asthma-related phenotype associations were investigated using regression analysis, adjusting for potential confounders where appropriate. Adults with the 38AA genotype had higher odds of current asthma (OR 3.2, P=0.013) and ever asthma (OR 2.2, P=0.045) compared with those with the 38GG genotype. Adjusting for atopy had minimal effect on this relationship. A positive linear trend was evident between the 38A allele and atopic dermatitis (OR 1.67, P=0.02). No associations were found between the A38G polymorphism and rhinitis, atopy, forced expiratory volume in 1 s (FEV(1)), forced vital capacity (FVC), airway responsiveness (AR) to histamine or peripheral blood eosinophil level (PBEL). An atopy-independent association between CC16 38AA and asthma prevalence was identified, suggesting the CC16 38A allele predisposes to adult asthma independent of Th1/Th2 processes. This finding is consistent with previous studies in children, but is the first reported association between CC16 A38G and asthma in adults. CC16 38A also displayed a positive linear trend with atopic dermatitis.

Adolescent↗
PubMed2005

Internet-based monitoring of asthma: a long-term, randomized clinical study of 300 asthmatic subjects.

BACKGROUND: Experience from other fields of internal medicine shows that Internet-based technology can be used to monitor various diseases. The new technology handles complex calculation programs easily, and it is a unique way of communicating. These advantages might be used in optimizing the treatment for asthmatic subjects because undertreatment is a common problem found in European asthmatic subjects. OBJECTIVE: We sought to investigate the outcome of monitoring and treatment using a physician-managed online interactive asthma monitoring tool and to assess whether the outcome differs from that of monitoring and treatment in an outpatient respiratory clinic or in primary care. METHODS: Three hundred asthmatic subjects were randomized to 3 parallel groups in a 6-month prospective study: (1) Internet-based monitoring (n = 100); (2) specialist monitoring (n = 100); and (3) general practitioner (GP) monitoring (n = 100). All the patients were examined on entry into the study and after 6 months of treatment. RESULTS: The treatment and monitoring with the Internet-based management tool lead to significantly better improvement in the Internet group than in the other 2 groups regarding asthma symptoms (Internet vs specialist: odds ratio of 2.64, P = .002; Internet vs GP: odds ratio of 3.26; P < .001), quality of life (Internet vs specialist: odds ratio of 2.21, P = .03; Internet vs GP: odds ratio of 2.10, P = .04), lung function (Internet vs specialist: odds ratio of 3.26, P = .002; Internet vs GP: odds ratio of 4.86, P < .001), and airway responsiveness (Internet vs GP: odds ratio of 3.06, P = .02). CONCLUSION: When physicians and patients used an interactive Internet-based asthma monitoring tool, better asthma control was achieved.

Adolescent↗
PubMed2005

Lung function in Greenlandic and Danish children and adolescents.

Respiratory morbidity in Inuit children is high. However, little is know regarding lung function measures in this population. The forced expiratory volumes in one second (FEV(1)) and forced vital capacity (FVC) in 888 Greenlandic Inuits (N=888) and Danes (N=477) aged 6-18 years were compared. Furthermore, associations between level of lung function and atopy and lifestyle factors were estimated in Greenlanders. The effect of height on FEV(1) and FVC was significantly different in Greenlanders and Danes, this difference in lung function increased with increasing height, and could not be explained by differences in age weight and BMI. Thus, Greenlanders taller than 130 cm had up to 300-400 ml higher FEV(1) and FVC compared with Danes of the same height. Among Greenlanders, those living in settlements had the highest levels of both FEV(1) and FVC. Greenlanders had elevated levels of FEV(1) and FVC compared with Danes. The Inuit having a shorter limb length in relation to trunk height may account for these differences. However, our finding that Greenlanders living in settlements had the highest lung function level also suggests a possible role of factors in the traditional Greenlandic lifestyle.

Adolescent↗
PubMed2005

Outcome in adulthood of asymptomatic airway hyperresponsiveness to histamine and exercise-induced bronchospasm in childhood.

BACKGROUND: Studies of the clinical outcome in adulthood of asymptomatic airway hyperresponsiveness (AHR) to histamine or exercise-induced bronchospasm (EIB) detected in childhood in general population samples are sparse and have produced conflicting results. OBJECTIVE: To describe the outcome of asymptomatic AHR to histamine and EIB. METHODS: Data from a 12-year follow-up study of a random population sample of individuals aged 7 to 17 years at enrollment were analyzed; only individuals without asthma at enrollment were included in the analysis. AHR to inhaled histamine, EIB, lung function, and sensitization to aeroallergens were measured. RESULTS: Among the 281 nonasthmatic participants studied, 58 (22%) had AHR to histamine, 33 (12%) had EIB, and 82 (29%) had AHR to histamine and/or EIB. At follow-up, 37.9% of individuals with AHR to histamine and 30% of individuals with EIB had developed current asthma, compared with only 5% of individuals in whom these test results were negative. In patients with AHR to histamine, parental asthma (odds ratio [OR], 12.6; 95% confidence interval [CI], 1.5-108.5), furred pets ownership (OR, 6.0; 95% CI, 1.2-19.6), and dermatitis and/or rhinitis in childhood (OR, 2.2; 95% CI, 1.1-5.1) predicted the subsequent development of asthma, whereas no risk factors for the development of asthma could be identified in individuals with EIB CONCLUSION: Asymptomatic AHR to histamine and EIB in childhood predict the subsequent development of asthma in adulthood. A genetic disposition to asthma, furred pets ownership, and concomitant rhinitis or dermatitis increase the risk of asthma development in individuals with AHR to histamine.

Adolescent↗
PubMed2005

Recognition of asthma in adolescents and young adults: which objective measure is best?

BACKGROUND: Objective assessment of airway function is important in epidemiologic studies of asthma to facilitate comparison between studies. Airway hyperresponsiveness (AHR), peak expiratory flow (PEF) variability, and bronchodilator reversibility (BR) are widely used as markers of airway lability in such studies. Data from a survey of a population sample of adolescents and young adults (n = 609; 288 males), aged 13-23 years, were analyzed to investigate whether AHR, PEF variability, and BR can be used interchangeably as markers of asthma in an epidemiological setting. METHODS: Case history, including self-reported and doctor-diagnosed asthma, smoking habits, and use of asthma medication, was obtained by interview and questionnaire. Lung function, airway responsiveness (positive test: PC20 FEV1 < 16 mg/mL histamine), PEF variability (positive test: amplitude percentage mean > 20%), BR (positive test: deltaFEV1 [(FEV1max - FEV1min)/FEV1max) 100] > 10%), blood eosinophil count, and skin prick test reactivity were measured by using standard techniques. RESULTS: The prevalence of a positive test was AHR 16.4%, PEFpos 13.3%, and BRpos 7.2%, respectively; 73.5% of the sample had three negative tests. Among the 74 participants with current self-reported asthma (12.2%), 34 subjects (46%) had more than one positive test. Using AHR as the only objective marker of asthma identified 93% of the participants with current asthma, whereas PEF and BR identified 45% and 10%, respectively. Confining the analysis to participants with only one positive test revealed that 61% of the subjects with isolated AHR had current asthma, whereas none of the subjects with isolated BRpos had asthma, and only one participant with isolated PEFpos had current asthma. Degree of histamine responsiveness was closer associated with other asthma-related factors, including self-reported asthma, use of asthma medication, and level of lung function, than PEF variability and bronchodilator responsiveness. CONCLUSIONS: Airway responsiveness to histamine, diurnal peak-flow variability, and bronchodilator reversibility cannot be used interchangeably as objective markers of asthma in epidemiologic studies. On the basis of the present findings, airway hyperresponsiveness to a nonspecific bronchoconstrictor is recommended as the objective marker of asthma-related airway lability.

Adolescent↗