Adults with concomitant atopic dermatitis and asthma have more frequent urgent healthcare utilization and less frequent scheduled follow-up visits than adults with atopic dermatitis or asthma only: a nationwide cohort study.

BACKGROUND: Atopic dermatitis (AD) and asthma often co-occur in the same patient, and healthcare utilization is related to disease severity of these diseases. OBJECTIVE: The objective of the study was to investigate differences in healthcare utilization in adults with concomitant AD and asthma compared to patients with asthma or AD only. METHODS: All Danish adults with a hospital diagnosis of AD, asthma or concomitant AD, and asthma recorded in national registries were included. Healthcare utilization data were obtained in 3-month intervals from 2 years prior to index date (the date of the first hospital diagnosis) and to 5 years after. RESULTS: A total of 12 409 patients with AD were included (11 590 with AD only and 819 with concomitant AD and asthma), and 65 539 with asthma only. Adults with concomitant AD and asthma had higher risk of hospitalization for AD (OR 1.38, 95% CI (1.15-1.67), P = 0.001) and asthma (OR 1.16, 95% CI (1.00-1.35), P = 0.047) compared to patients with only AD and asthma, respectively. These patients also had fewer visits in outpatient clinics for AD (OR 0.10, 95% CI (0.08-0.12), P < 0.001) and asthma (OR 0.34, 95% CI (0.29-0.39), P < 0.001) compared to patients with only AD or asthma. Outpatient clinic visits for rhinitis were more frequent among patients with concomitant AD and asthma compared to patients with only AD or asthma. CONCLUSION: Adults with concomitant AD and asthma had different patterns of healthcare utilization compared to adults with AD or asthma alone, suggesting that improvements in management and monitoring may reduce unscheduled healthcare visits and lower healthcare costs.

Higher vs lower doses of dexamethasone in patients with COVID-19 and severe hypoxia (COVID STEROID 2) trial: Protocol and statistical analysis plan.

BACKGROUND: The coronavirus disease 2019 (COVID-19) pandemic has resulted in millions of deaths and overburdened healthcare systems worldwide. Systemic low-dose corticosteroids have proven clinical benefit in patients with severe COVID-19. Higher doses of corticosteroids are used in other inflammatory lung diseases and may offer additional clinical benefits in COVID-19. At present, the balance between benefits and harms of higher vs. lower doses of corticosteroids for patients with COVID-19 is unclear. METHODS: The COVID STEROID 2 trial is an investigator-initiated, international, parallel-grouped, blinded, centrally randomised and stratified clinical trial assessing higher (12 mg) vs. lower (6 mg) doses of dexamethasone for adults with COVID-19 and severe hypoxia. We plan to enrol 1,000 patients in Denmark, Sweden, Switzerland and India. The primary outcome is days alive without life support (invasive mechanical ventilation, circulatory support or renal replacement therapy) at day 28. Secondary outcomes include serious adverse reactions at day 28; all-cause mortality at day 28, 90 and 180; days alive without life support at day 90; days alive and out of hospital at day 90; and health-related quality of life at day 180. The primary outcome will be analysed using the Kryger Jensen and Lange test adjusted for stratification variables and reported as adjusted mean differences and median differences. The full statistical analysis plan is outlined in this protocol. DISCUSSION: The COVID STEROID 2 trial will provide evidence on the optimal dosing of systemic corticosteroids for COVID-19 patients with severe hypoxia with important implications for patients, their relatives and society.

Small intestinal absorption in patients with chronic obstructive pulmonary disease complicated by cor pulmonale - A pilot study.

BACKGROUND: Cor pulmonale is a common complication to Chronic Obstructive Pulmonary Disease (COPD), and may result in increased pressure in the inferior caval vein and stasis of the liver. The chronic pulmonary hypertension may lead to stasis in the veins from the small intestine and thereby compromise absorption of nutrients. AIM: To investigate whether patients with pulmonary hypertension have reduced absorption capacity compared to COPD patients without cor pulmonale. METHODS: Absorption of d-xylose (25 g) and zinc (132 mg), administered as a single dose, was tested in 14 COPD patients, seven with and seven without cor pulmonale. The presence of cor pulmonale was determined by echocardiography. The concentration of d-xylose and zinc were measured in peripheral blood one, two and three hours after ingestion and used as markers of absorption. Furthermore, urine was collected for five hours to determine the amount of excreted d-xylose. RESULTS: No significant difference in absorption of d-xylose (p = 0.28) or zinc (p = 0.51) was found between the two groups. However, a trend towards a delay in d-xylose absorption, as assessed by time-to-peak concentration, was observed in patients with cor pulmonale (p = 0.08). There was no significant difference in the amount of excreted d-xylose in the urine between the groups (p = 0.52). No correlation was found between the tricuspid regurgitation gradient and the absorption of both test-markers (rs = 0.34 and rs = -0.25). Likewise, no correlations were found between the inferior caval pressure during the in- and expiration phases and the absorption of d-xylose (rs = -0.09 rs = 0.23) or zinc (rs = -0.39, rs = -0.39). CONCLUSION: We found no indications that small intestinal absorption is affected in a clinically relevant degree in patients with cor pulmonale.

Determinants of low risk of asthma exacerbation during pregnancy.

BACKGROUND: Assessment of asthma control every 4-6 weeks during pregnancy is recommended to reduce risk of exacerbation, and by that improve outcome. OBJECTIVE: To identify determinants of pregnancies with low risk of asthma exacerbation. METHODS: All pregnant women enrolled into the Management of Asthma during Pregnancy (MAP) programme at Hvidovre Hospital since 2007. Assessment of asthma control, adjustment of treatment, spirometry and measurement of exhaled nitric oxide (FE NO) were performed, and baseline characteristics and exacerbation history were collected at enrolment. Determinants of low-exacerbation risk pregnancies were identified by logistic regression analysis (stepwise backward elimination). RESULTS: In 1283 pregnancies, 107 exacerbations were observed. Multiple regression analysis revealed that no history of pre-pregnancy exacerbations (P < .001), no prescribed controller medication (P < .001), and clinically stable asthma at enrolment (P = .002) were significantly associated with low risk of exacerbation during pregnancy; with these combined characteristics, only two of 385 pregnancies were complicated by an exacerbation (OR 0.04, 95% CI 0.01-0.18, P < .001). CONCLUSION AND CLINICAL RELEVANCE: Clinically stable asthma at enrolment, together with no history of previous exacerbations and no prescribed controller medication, is a determinant of low risk of an asthma exacerbation during pregnancy, which may guide clinicians in individualizing surveillance of asthma during pregnancy.

Overweight in childhood and adolescence: Does it lead to airway hyperresponsiveness in adulthood?

BACKGROUND: Obesity is increasing worldwide among children and adolescents, and has been associated with an increased incidence of asthma. However, the mechanisms underlying this association are incompletely understood. OBJECTIVE: In this cohort study we aimed to investigate whether being overweight in childhood and adolescence is associated with an increased risk of airway hyperresponsiveness (AHR), a hallmark of asthma, in early adulthood. METHODS: Of 527 subjects from a random population sample of children and adolescents (7-17 years) examined at baseline, a total of 184 subjects completed the follow-up visit 20 years later and were included in the present analysis. Both visits included assessment of height and weight, case history and spirometry. At both visits, bronchial provocation tests were performed using either histamine (baseline) or methacholine (follow-up). In addition, fractional exhaled nitric oxide (FeNO) was measured at follow-up. RESULTS: No significant difference in the prevalence of AHR at follow-up was found between subjects who were overweight or obese at baseline visit (n = 26) (pediatric definition, body mass index ≥ 85%percentile) and normal weight subjects (n = 158) (positive bronchial provocation tests: 15.4% vs. 22.2%, respectively, p = 0.35). Likewise, follow-up FeNO levels did not differ significantly between subjects who were lean and those who were overweight or obese at baseline (geometric mean (95% confidence interval [CI]) 15.1 (13.7, 16.6) parts per billion (ppb) versus 13.0 (10.6, 15.9) ppb, p = 0.23). CONCLUSION: In children and adolescents, being obese or overweight seems not to be associated with an increased risk of AHR or increased FeNO levels in early adulthood.

Exacerbations of asthma during pregnancy: Impact on pregnancy complications and outcome.

Asthma is common among pregnant women, and the incidence of asthma exacerbations during pregnancy is high. This literature review provides an overview of the impact of exacerbations of asthma during pregnancy on pregnancy-related complications. The majority of published retrospective studies reveal that asthma exacerbations during pregnancy increase the risk of pre-eclampsia, gestational diabetes, placental abruption and placenta praevia. Furthermore, these women also have higher risk for breech presentation, haemorrhage, pulmonary embolism, caesarean delivery, maternal admission to the intensive care unit and longer postpartum hospital stay. Asthma has been associated with increased risk of intrauterine growth retardation, small-for-gestational age, low birth weight, infant hypoglycaemia and preterm birth, but more recent prospective studies have not revealed significant associations with regard to these outcomes. In conclusion, asthma exacerbations during pregnancy are associated with complications of pregnancy, labour and delivery. Prevention of exacerbations is essential to reduce the risk of complications and poor outcome.

Add-on montelukast to inhaled corticosteroids protects against excessive airway narrowing.

RATIONALE: Excessive airway narrowing in response to broncho-active stimuli is a predictor for severe exacerbations in asthma. Leukotriene receptor antagonists (LTRAs) have complementary properties to inhaled corticosteroids (ICS) on asthma control. OBJECTIVES: The LTRA montelukast may provide an additional protection against excessive airway narrowing. We tested the add-on effects of montelukast on the maximal response plateau and PD(20) to inhaled methacholine in asthmatics on a stable dose of ICS. METHODS: Thirty-one patients with allergic asthma [14M/17F, 19-50 years, forced expiratory volume in 1 s (FEV(1)) >70% pred., PD(20) <3.9 micromol methacholine], with a twice documented response plateau to methacholine, were randomized in a double-blind (montelukast 10 mg or matching placebo once daily), 12-week parallel study. Bronchoprovocation tests with methacholine (0.03-256 micromol or > or =40% decline in FEV(1)) were repeated every 4 weeks and after wash-out. The main study objectives were changes from baseline in maximal FEV(1) decline at the response plateau (i.e. >2 post-dose FEV(1) values within 5%) and PD(20) to methacholine after 12 weeks' treatment. RESULTS: Neither treatment affected baseline FEV(1) (P=0.62). Compared with placebo, montelukast significantly decreased the maximal response plateau to methacholine (mean difference 9.4%; 95% confidence interval 3.9-15.7; P<0.005), improved the FEV(1) decline (mean change in FEV(1) decline was 2.1% [montelukast] and -0.8% [placebo], respectively, P<0.05), and increased PD(20) methacholine (mean change in PD(20) of 5.3 [montelukast] and 1.4 [placebo] doubling doses, respectively, P<0.001). CONCLUSION: Add-on montelukast to ICS has disease-modifying effects in adults with persistent asthma, and hence reduces the risk of excessive airway narrowing (NCT 00913328).

Prevalence and severity of self-reported asthma in young adults, 1976-2004.

The aim of the present study was to describe the prevalence and severity of asthma in young Danish adults over three decades. Males and females aged 20-35 yrs were sampled from the population of Copenhagen for the three surveys (1976-1978, 1991-1993 and 2001-2004). A total of 3,285 (46% male) subjects answered a questionnaire, and had their height, weight, forced expiratory volume in 1 s (FEV1) and forced vital capacity measured. The prevalence of self-reported asthma was 1.5, 4.7 and 6.9%, respectively, in the three surveys (p<0.001). An increasing prevalence of asthma was observed in both males and females, although it was highest among females. The difference in FEV1 between asthmatic and nonasthmatic subjects gradually increased, being 2.3 (p = 0.56) and 14.2% of the predicted value (p<0.001), respectively, in 1976-1978 and 2001-2004. From the 1991-1994 survey, increasing body mass index, especially >30 kg.m(-2), was associated with a lower percentage predicted FEV1 (p< or =0.005), and further analyses suggested an additive effect of asthma and obesity on FEV1. The proportion of smokers declined from 60 to 38% (p<0.001). The prevalence and severity of asthma have continued to increase over the last three decades among young Danish adults, and the observed increase in severity seems, at least partly, to be related to the increase in prevalence of obesity.

Association between obesity and asthma in a twin cohort.

BACKGROUND: Obesity is linked to asthma in a yet poorly understood manner. We examined the relationship between obesity and asthma in a population-based sample of twins. METHODS: From the cohorts born between 1953 and 1982, who were enrolled in The Danish Twin Registry, a total of 29 183 twin individuals participated in a nationwide questionnaire study, where data on height, weight and asthma were collected. Latent factor models of genetic and environmental effects were fitted using maximum likelihood methods. RESULTS: The age-adjusted risk of asthma was increased both in obese females, OR = 1.96 (1.45-2.64), P < or = 0.001 and in obese males, OR = 1.59 (1.08-2.33), P = 0.02. According to best-fitting models, the heritability for obesity was 81% in males and 92% in females, whereas the heritability for asthma was 78% and 68% in males and females respectively. The age-adjusted genetic liabilities to obesity and asthma were significantly correlated only in females, r = 0.28 (0.16-0.38). CONCLUSIONS: Obese subjects have an increased risk for asthma, which in females seems partly because of common genes.

Findings on the atopic triad from a Danish twin registry.

OBJECTIVE: To estimate to what extent the same genetic and environmental risk factors influence asthma, hay fever and eczema. DESIGN: From the nationwide Danish Twin Registry, twin cohorts born between 1953 and 1982 were contacted for a questionnaire survey, and a total of 29 183 twin individuals (86%) responded. Subjects were classified as cases when responding affirmatively to three questions about the lifetime occurrence of asthma, hay fever and eczema. Variance components twin analysis was conducted using maximum likelihood methods. RESULTS: The phenotypic (within-subject) correlations in liability between the different diseases were 0.57 (95% CI 0.54-0.59) for asthma and hay fever, 0.40 (95% CI 0.36-0.42) for asthma and eczema, and 0.33 (95% CI 0.29-0.36) for hay fever and eczema. Decomposition of these correlations into their genetic and environmental contributions showed that shared genes explained between 70% and 85% of the correlation between the different diseases. The remaining parts were explained by environmental factors shared between the diseases. CONCLUSION: To a large extent, atopic diseases share a common genetic background, although disease-specific genes also play a considerable role. These results can prove informative when counselling families with atopy, and may furthermore be used to guide the search for pleiotropic genes of importance for these diseases.

Multivariate genetic analysis of atopy phenotypes in a selected sample of twins.

BACKGROUND: Atopic traits often co-occur and this can potentially be caused by common aetiological relationships between traits, i.e. a common genetic or a common environmental background. OBJECTIVE: To estimate to what extent the same genetic and environmental factors influence wheeze, rhinitis, airway hyper-responsiveness (AHR), and positive skin prick test (posSPT) in a sample of adult twins. METHODS: Within a sampling frame of 21,162 twin subjects, 20-49 years of age, from the Danish Twin Registry, a total of 575 subjects (256 intact pairs and 63 single twins), who either themselves and/or their co-twins reported a history of asthma at a nationwide questionnaire survey, were clinically examined. Symptoms of wheeze and rhinitis were obtained by interview; airway responsiveness and skin test reactivity were measured using standard techniques. Correlations in liability between the different traits were estimated and latent factor models of genetic and environmental effects were fitted to the observed data using maximum likelihood methods. RESULTS: The various phenotypic correlations between wheeze, rhinitis, AHR and posSPT were all significant and ranged between 0.50 and 0.86. Traits that showed highest genetic correlations were wheeze-rhinitis (rho(A)=0.95), wheeze-AHR (rho(A)=0.85) and rhinitis-posSPT (rho(A)=0.92), whereas lower genetic correlations were observed for rhinitis-AHR (rho(A)=0.43) and AHR-posSPT (rho(A)=0.59). Traits with a high degree of environmental sharing were rhinitis-posSPT (rho(E)=0.92) and wheeze-posSPT (rho(E)=0.71), whereas a lower environmental correlation was seen for wheeze-rhinitis (rho(E)=0.25). The estimates were corrected for ascertainment and adjusted for age, sex, inhaled corticosteroids and smoking. CONCLUSIONS: Different atopic conditions share, to a large extent, a common genetic background. In particular, upper and lower respiratory symptoms seem to be different phenotypic expressions of a common set of genes. These results add new insight into the origins of clinical heterogeneity within atopy and should stimulate the search for pleiotropic genes of importance for these conditions.

Risk factors for asthma in young adults: a co-twin control study.

BACKGROUND: The liability to asthma is influenced both by genetic and environmental factors. The objective of this study was to identify risk factors for asthma in young adult twin pairs during an 8-year period. METHODS: From the birth cohorts 1953-1982 of the Danish Twin Registry, 6,090 twin pairs who were initially unaffected with respect to asthma at a nationwide questionnaire-based study in 1994 participated in a similar follow-up study in 2002. Subjects were regarded incident asthma cases when responding affirmatively to the question 'Do you have, or have you ever had asthma'? in 2002. Pairs in which only one twin developed asthma -- discordant pairs -- were identified and conditional logistic regression was applied to detect effects of risk factors. RESULTS: A total of 126 monozygotic (MZ) and 273 dizygotic (DZ) discordant twin pairs were identified. In MZ twins hay fever (OR = 3.16, 95% CI: 1.29-7.73, P = 0.007) and exercise (OR for inactivity = 0.35, 95% CI: 0.13-0.91, P = 0.023) were significantly associated with asthma, whereas in DZ twins, hay fever (OR = 2.44, 95% CI: 1.44-4.13, P = 0.001), eczema (OR = 1.96, 95% CI: 1.02-3.78, P = 0.040), female sex (OR between males and females = 0.54, 95% CI: 0.36-0.80, P = 0.002), and increasing levels of body mass index (BMI; OR per unit = 1.11, 95% CI: 1.02-1.20, P = 0.009) were significant predictors of asthma. CONCLUSIONS: Hay fever, eczema, female sex, exercise and increasing levels of BMI were risk factors for asthma in young adults. The different risk profile observed in MZ twins compared with DZ twins may reflect an underlying genetic vulnerability shared between those risk factors and asthma.

Inhaled corticosteroids and decline of lung function in community residents with asthma.

BACKGROUND: Inhaled corticosteroids (ICS) constitute the cornerstone of treatment for asthma. Many studies have reported beneficial short term effects of these drugs, but there are few data on the long term effects of ICS on the decline in forced expiratory volume in 1 second (FEV(1)). This study was undertaken to determine whether adults with asthma treated with ICS have a less pronounced decline in FEV(1) than those not treated with ICS. METHODS: Two hundred and thirty four asthmatic individuals from a longitudinal epidemiological study of the general population of Copenhagen, Denmark were divided into two groups; 44 were treated with ICS and 190 were not treated with ICS. The annual decline in FEV(1) was measured over a 10 year follow up period. RESULTS: The decline in FEV(1) in the 44 patients receiving ICS was 25 ml/year compared with 51 ml/year in the 190 patients not receiving this treatment (p<0.001). The linear regression model with ICS as the variable of interest and sex, smoking, and wheezing as covariates showed that treatment with ICS was associated with a less steep decline in FEV(1) of 18 ml/year (p = 0.01). Adjustment for additional variables including age, socioeconomic status, body mass index, mucus hypersecretion, and use of other asthma medications did not change these results. CONCLUSIONS: Treatment with ICS is associated with a significantly reduced decline in ventilatory function.

Risk factors for rehospitalisation in COPD: role of health status, anxiety and depression.

The aim of the present study was to analyse the risk of rehospitalisation in patients with chronic obstructive pulmonary disease and associated risk factors. This prospective study included 416 patients from a university hospital in each of the five Nordic countries. Data included demographic information, spirometry, comorbidity and 12 month follow-up for 406 patients. The hospital anxiety and depression scale and St. George's Respiratory Questionnaire (SGRQ) were applied to all patients. The number of patients that had a re-admission within 12 months was 246 (60.6%). Patients that had a re-admission had lower lung function and health status. A low forced expiratory volume in one second (FEV1) and health status were independent predictors for re-admission. Hazard ratio (HR; 95% CI) was 0.82 (0.74-0.90) per 10% increase of the predicted FEV1 and 1.06 (1.02-1.10) per 4 units increase in total SGRQ score. The risk of rehospitalisation was also increased in subjects with anxiety (HR 1.76 (1.16-2.68)) and in subjects with low health status (total SGRQ score >60 units). When comparing the different subscales in the SGRQ, the closest relation between the risk of rehospitalisation was seen with the activity scale (HR 1.07 (1.03-1.11) per 4 unit increase). In patients with low health status, anxiety is an important risk factor for rehospitalisation. This may be important for patient treatment and warrants further studies.

Prevalence and predictors of atopy among young Danish adults.

BACKGROUND: The prevalence of atopic diseases is increasing in western countries, and environmental exposures in childhood may influence development of atopic sensitization. OBJECTIVE: To investigate the prevalence and predictors of atopy among young Danish adults. METHODS: Of 940 invited subjects, aged 19-29 years, complete data were obtained from 525 (56%) subjects. All completed a questionnaire concerning asthma, rhinitis, preschool nursery care, smoking habits, family size, education and employment. A skin prick test was performed, and pulmonary function was measured using standard techniques. Atopy was defined as a positive skin prick test. RESULTS: The frequency of atopy was 32% (males 43% vs. females 23%, P < 0.001). We found a positive association between atopy and atopic dermatitis (P < 0.05), rhinitis (P < 0.001), itching when eating nuts (P < 0.001) and current asthma (P < 0.001). There was an inverse relation between atopy and having furred pets in childhood (P < 0.05), passive smoking in childhood (P < 0.01) and current passive smoking (P < 0.05). An increasing number of siblings was inversely related to atopy to grass (P < 0.05); however, only an increasing number of older siblings seemed to protect from atopy to grass (P < 0.05). Subjects who had never attended a day-care centre had significantly more atopy to grass (P < 0.05). No significant association was found between atopy and airway infections requiring hospitalization before the age of 5 years, or between atopy and bedroom sharing in childhood. CONCLUSION: Atopy is common among young Danish adults, especially in males. Participants were less likely to be atopic, especially to grass allergen, if they came from large families, had kept furred pets as children, and had been exposed to tobacco smoke.

Exogenous female sex steroid hormones and risk of asthma and asthma-like symptoms: a cross sectional study of the general population.

BACKGROUND: Recent evidence suggests a role for hormonal factors in the aetiology of asthma. METHODS: Data from a large study of women selected from the general population were used to relate treatment with oral hormonal contraceptives (OCP) and postmenopausal hormone replacement therapy (HRT) to the following asthma indicators: self-reported asthma, wheezing, cough at exertion, and use of medication for asthma. The study sample comprised 1536 premenopausal and 3016 postmenopausal women who participated in the third round of the Copenhagen City Heart Study in 1991-4. A total of 377 women were taking OCP (24.5% of premenopausal women) and 458 were on HRT (15.2% of postmenopausal women). RESULTS: In premenopausal women 4.8% reported having asthma. The prevalence of self-reported asthma, wheeze, use of asthma medication, and cough at exertion was not significantly related to use of OCP. In postmenopausal women the prevalence of self-reported asthma was 6.2%. A weak but consistent association was observed between HRT and self-reported asthma (OR 1.42 (95% CI 0.95 to 2.12)), wheeze (OR 1.29 (95% CI 1.02 to 1.64)), cough at exertion (OR 1.34 (95% CI 1.01 to 1.77)), and use of asthma medication (OR 1.45 (95% CI 0.97 to 2.18)). CONCLUSIONS: In this study of the general population no relationship was found between the use of OCP and asthma. Although an association was observed between HRT and asthma and asthma-like symptoms, this was relatively weak and it is concluded that there is no necessity to change present prescription practice.

Cigarette smoking and asthma.

Cigarette smoking is a well-know health hazard, probably not least for patients suffering from asthma. This review gives a short overview concerning the effects of passive and active smoking on the inception and outcome with regard to longitudinal changes in lung function and mortality for patients with asthma. Substantial evidence suggests that smoking affects asthma adversely. Exposure to environmental tobacco smoke in children, especially maternal smoking, may be a significant risk factor for asthma. Environmental tobacco exposure in patients with established asthma is not only associated with more severe symptoms, but also with lower quality of life, reduced lung function, and increased health care utilisation for asthma, including hospital admissions. Active smoking appears not to be a significant risk factor for asthma, but it is associated with worse outcome with regard to both longitudinal changes in lung function and asthma-related mortality. Based on the current knowledge, it therefore seems of utmost importance to encourage patients with asthma not to smoke. In line with this, patients with asthma should be given full support in their right to a smoke-free environment.

[Atopy among children and adolescents in Copenhagen]. / Atopi hos børn og unge i København.

INTRODUCTION: Atopy is related to the presence of rhinitis and asthma, but our knowledge about its longitudinal predictors is limited. METHODS: Data from a 6-yr follow-up study of a population sample of children and adolescents (n = 408), aged 7 to 17 yr. at enrollment, were analysed to investigate the prevalence and predictors of atopy. Case history, including allergic diseases and smoking habits, was elicited by interview and questionnaire. Skin prick test reactivity to common allergens, total serum IgE, airway responsiveness, and pulmonary function were measured. RESULTS: The point prevalence of atopy increased from the first to the second survey, 26% and 44%, respectively; 23% of the participants were atopic only at the second survey. Sensitisation to house dust mites (HDM), grass, dogs, cats, and birch pollen increased significantly in both the males and the females. However, no gender differences in the prevalence of positive reactions were found at the first survey, whereas atopy to grass and HDM was significantly more prevalent in males than in females at the second survey. Analysis of the data solely on participants who were non-atopic at the first survey showed that exposure to maternal smoking (OR 2.0, CI 1.3-3.1; p = 0.002), increased serum IgE (OR 1.7, CI 1.2-2.3; p = 0.001), new asthma (OR 1.6, CI 1.2-2.7; p = 0.03), and new rhinitis (OR 2.1, CI 1.2-3.6; p = 0.01) were associated with an increased risk of a positive skin prick test at the second survey. CONCLUSION: This longitudinal population study showed an increase in the point prevalence of atopy in Danish children and adolescents; and, furthermore, that exposure to maternal smoking during childhood, increased serum IgE, and new symptoms of asthma or rhinitis were associated with an increased risk of developing sensitisation to common aeroallergens in late adolescence.

Prevalence and predictors of rhinitis in Danish children and adolescents.

BACKGROUND: The prevalence of self-reported symptoms of allergic rhinitis is increasing in many countries, but the reasons for this trend are not well understood. Data from a 6-year follow-up study of a population sample of children and adolescents (n=408), aged 7-17 years at enrolment in 1986, were analyzed to investigate the prevalence and predictors of self-reported rhinitis. METHODS: Case history was used to assess the presence or absence of rhinitis (sneezing and running or blocked nose not associated with a cold), asthma, and eczema. Pulmonary function, skin prick test reactivity, and airway responsiveness to histamine were measured in all participants; a screening test for IgE antibodies to common allergens (Magic Lite SQ, Allergy Screen, ALK, Denmark) was performed in 237 (58%) of the participants. RESULTS: The point prevalence of rhinitis increased from the first to the second survey, 14% and 22%, respectively; 54 (13%) of the subjects reported rhinitis only at the second survey (new rhinitis). Confining the analysis to participants without symptoms of rhinitis at the first survey showed that self-reported eczema (relative risk [RR] 2.3, 95% confidence interval [CI] 1.2-4.7), airway hyperresponsiveness (RR 2.5, CI 1.8-3.0), atopy to grass pollen (RR 2.6, CI 1.7-3.3), atopy to dog dander (RR 2.4, CI 1.6-3.3), and atopy to house-dust mite (RR 2.7, CI 1.4-5.2) at the first survey predicted an increased risk of the presence of rhinitis at the second survey. A positive Allergy Screen test at enrollment was associated with an increased risk of self-reported rhinitis at follow-up (RR 2.4, CI 1.4-3.4). CONCLUSIONS: This longitudinal population study of children and adolescents showed an age-related increase in the point prevalence of self-reported rhinitis; furthermore, sensitization to common aeroallergens, airway hyperresponsiveness, and the presence of self-reported eczema were significantly associated with an increased risk of subsequent development of rhinitis.