Childhood atopic dermatitis is associated with cardiovascular risk factors in young adulthood-A population-based cohort study.

BACKGROUND: Studies have indicated that atopic dermatitis (AD) is associated with an increased risk of cardiovascular disease (CVD). However, data are conflicting. Furthermore, the longitudinal effect of childhood AD on cardiovascular risk factors in young adulthood is less investigated. OBJECTIVES: To assess associations between AD in childhood and CVD risk factors in young adulthood. METHODS: The study encompasses longitudinal data from a population-based birth cohort. Participants with data up to age 24 years were included (n = 2270). The primary outcomes were body mass index (BMI), waist circumference (WC), body fat per cent (BF%) and blood pressure (BP) at 24 years. The secondary outcome was blood lipids. Severe AD was defined as AD in combination with sleep disturbance due to itching. RESULTS: In total, 18.6% (n = 420) had AD at 24 years. Males with AD had higher BMI (ßAdj. 0.81, 95% CI 0.15-1.47), BF% (ßAdj. 1.19, 95% CI 0.09-2.29), systolic BP (ßAdj. 1.92, 95% CI 0.02-3.82), total cholesterol (ßAdj. 0.14, 95% CI 0.00-0.28) and LDL cholesterol (ßAdj. 0.15, 95% CI 0.02-0.27) compared with males without AD. No associations were seen in females. Current AD with prepubertal onset was associated with increased BMI in both males (ßAdj. 0.89, 95% CI 0.11-1.67) and females (ßAdj. 0.72, 95% CI 0.11-1.33). At 24 years, 23.1% (n = 97) of all with AD, had severe disease, which was significantly associated with overweight in both sexes, with BMI (ßAdj. 1.83, 95% CI 0.72-2.94), WC (ßAdj. 4.03, 95% CI 1.54-6.52) and BF% (ßAdj. 2.49, 95% CI 0.60-4.39) in females and with BF% (ßAdj. 2.96, 95% CI 0.23-5.69) in males, compared with peers with mild to moderate AD. CONCLUSION: AD in males appears to be associated with CVD risk factors in young adulthood. The duration and severity of AD seem to be of importance in both sexes.

Young children's voices in an unlocked Sweden during the COVID-19 pandemic.

AIMS: During the COVID-19 pandemic, Sweden was one of the few countries that rejected lockdowns in favour of recommendations for restrictions, including careful hand hygiene and social distancing. Preschools and primary schools remained open. Several studies have shown negative impacts of the pandemic on children, particularly high levels of anxiety. The study aim was to explore how Swedish school-aged children aged 6-14 years, experienced the COVID-19 pandemic and their perceived anxiety. METHODS: In total, 774 children aged 6-14 years and their guardians answered an online questionnaire containing 24 questions, along with two instruments measuring anxiety: the Children's Anxiety Questionnaire and the Numerical Rating Scale. A convergent parallel mixed-methods design was used for analysing the quantitative and qualitative data. Each data source was first analysed separately, followed by a merged interpretative analysis. RESULTS: The results showed generally low levels of anxiety, with no significant sex differences. Children who refrained from normal social activities or group activities (n=377) had significantly higher levels of anxiety. Most of the children were able to appreciate the bright side of life, despite the social distancing and refraining from activities, which prevented them from meeting and hugging their loved ones. CONCLUSIONS: These Swedish children generally experienced low levels of anxiety, except those who refrained from social activities. Life was nonetheless mostly experienced as normal, largely because schools remained open. Keeping life as normal as possible could be one important factor in preventing higher anxiety and depression levels in children during a pandemic.

Prevalence and characteristics of atopic dermatitis among young adult females and males-report from the Swedish population-based study BAMSE.

BACKGROUND: There is limited knowledge regarding prevalence and characteristics of atopic dermatitis (AD) among young adults in the general population. OBJECTIVES: To study AD among young adults in a Swedish population-based birth cohort, with a particular focus on prevalence, sex differences including risk for AD at different ages, disease course and characteristics of AD at 24 years. METHODS: The BAMSE cohort includes 4089 individuals who have been followed regularly from birth to age 24 years regarding AD and atopic diseases. For this study 3055 individuals who answered questions regarding AD at the 24-year follow-up were included. All were invited to a clinical examination including skin examination, evaluation by William's criteria and collection of blood for analysis of specific IgE, and 2264 individuals chose to participate. RESULTS: At 24 years, the 12-month prevalence of AD was 17.8% and more females than males had AD (20.5% vs. 14.8%), P < 0.0001. The point prevalence of ongoing AD at clinical examination was 8.0%. AD severity as assessed by Patient-Oriented Eczema Measure (POEM) did not differ between sexes. The proportion of adult onset of AD was 16.9% (92 of 543), females 17.3% vs. males 16.4%. More females than males with AD at 24 years reported disturbed sleep due to itch (26.1% vs. 15.5%, P < 0.003). IgE sensitization was less common among females with AD than males with AD (61.3% vs. 79.6%, P < 0.0001). In addition, male sex (female sex being the reference) was associated with increased odds for AD the first year of life (OR: 1.31, 95% CI; 1.10-1.56), and decreased odds of AD in adolescence and young adulthood (OR: 0.66, 95% CI; 0.55-0.80). CONCLUSIONS: Atopic dermatitis is a common disease among young adults, and even though more females than males have AD at 24 years, adult onset of AD seems to be equally prevalent among both sexes in young adulthood.

Atopic dermatitis at preschool age and contact allergy in adolescence: a population-based cohort study.

BACKGROUND: Atopic dermatitis (AD) is characterized by an impaired skin barrier, which can allow enhanced penetration of allergens. It is not clear whether AD influences the risk of developing contact allergy. OBJECTIVES: To examine the association between AD at preschool age and contact allergy at 16 years of age. METHODS: At 16 years of age, 2215 adolescents from the population-based cohort BAMSE were included. These adolescents had been followed with repeated questionnaires regarding AD throughout childhood, and contact allergy was assessed by skin patch test at 16 years. RESULTS: AD at preschool age was associated with contact allergy to at least one of the tested substances at 16 years of age among boys [adjusted odds ratio (OR) 1·51, 95% confidence interval (CI) 1·03-2·20] but not among girls (adjusted OR 0·77, 95% CI 0·54-1·10). AD at preschool age was not associated with contact allergy to nickel in either boys or girls. In contrast, AD at preschool age was associated with contact allergy to fragrance mix I (adjusted OR 3·10, 95% CI 1·66-5·80). This association was observed especially for AD at preschool age in combination with IgE sensitization to airborne or food allergens (adjusted OR 3·80, 95% CI 1·67-8·61). CONCLUSIONS: The results suggest that AD in early childhood may be associated with contact allergy to fragrances, but not to nickel, in adolescence.

Environmental peanut exposure increases the risk of peanut sensitization in high-risk children.

BACKGROUND: High household peanut consumption is associated with the development of peanut allergy, especially when peanut allergic cases are compared against atopic controls; thus, environmental peanut exposure (EPE) may be a risk factor for peanut sensitization and allergy. In this study, we explored the relationship between EPE and school-age peanut sensitization in a population-based cohort. METHODS: Maternal bed dust was collected postnatally, and EPE was quantified using a polyclonal peanut ELISA. Peanut sensitization was assessed by specific IgE to peanut extract and sIgE to peanut protein component allergens Ara h 1, 2 or 3 ≥ 0.35kU/L (primary peanut sensitization). Initial nested case-control analysis was performed comparing peanut-sensitized cases against high-risk controls (matched for parental atopy) (n = 411) using a conditional regression analysis. This was followed by whole cohort analysis (n = 1878) comparing EPE against peanut sIgE sensitization at ages 4 and 8 years using generalized estimating equations and against primary peanut sensitization at age 8 years using a logistic regression model. Finally, a subgroup analysis was performed comparing the impact of EPE in peanut-sensitized vs egg-sensitized, peanut-tolerant individuals using logistic regression analysis. Levels of EPE were compared between groups using the Mann-Whitney U test. RESULTS: In the nested case-control analysis, a higher level of EPE around birth was associated with peanut-specific IgE sensitization at age 4 years (OR=1.41, 95% CI:1.05-1.90) and primary peanut sensitization at age 8 years (OR=2.11, 95% CI:1.38-3.22) compared against high-risk controls. When the whole BAMSE cohort was assessed, EPE was no longer associated with peanut sensitization; however, on subgroup analysis, EPE was associated with primary peanut sensitization when compared against egg-sensitized peanut-tolerant controls with an adjusted odds ratio of 1.44 per unit EPE (95% CI:1.06-1.94). There was no significant interaction between EPE and FLG loss-of-function mutations, egg sensitization at age 4 years, infantile eczema or parental atopy on peanut sensitization. CONCLUSIONS: Higher levels of environmental exposure to peanut in the first few months of life appear to increase the probability of developing school-age peanut sensitization in atopic children (based on egg sensitization and parental atopy).

Treatment of allergic rhinitis using mobile technology with real-world data: The MASK observational pilot study.

BACKGROUND: Large observational implementation studies are needed to triangulate the findings from randomized control trials as they reflect "real-world" everyday practice. In a pilot study, we attempted to provide additional and complementary insights on the real-life treatment of allergic rhinitis (AR) using mobile technology. METHODS: A mobile phone app (Allergy Diary, freely available in Google Play and Apple App stores) collects the data of daily visual analog scales (VAS) for (i) overall allergic symptoms, (ii) nasal, ocular, and asthma symptoms, (iii) work, as well as (iv) medication use using a treatment scroll list including all medications (prescribed and over the counter (OTC)) for rhinitis customized for 15 countries. RESULTS: A total of 2871 users filled in 17 091 days of VAS in 2015 and 2016. Medications were reported for 9634 days. The assessment of days appeared to be more informative than the course of the treatment as, in real life, patients do not necessarily use treatment on a daily basis; rather, they appear to increase treatment use with the loss of symptom control. The Allergy Diary allowed differentiation between treatments within or between classes (intranasal corticosteroid use containing medications and oral H1-antihistamines). The control of days differed between no [best control], single, or multiple treatments (worst control). CONCLUSIONS: This study confirms the usefulness of the Allergy Diary in accessing and assessing everyday use and practice in AR. This pilot observational study uses a very simple assessment (VAS) on a mobile phone, shows novel findings, and generates new hypotheses.

The Allergic Rhinitis and its Impact on Asthma (ARIA) score of allergic rhinitis using mobile technology correlates with quality of life: The MASK study.

Mobile technology has been used to appraise allergic rhinitis control, but more data are needed. To better assess the importance of mobile technologies in rhinitis control, the ARIA (Allergic Rhinitis and its Impact on Asthma) score ranging from 0 to 4 of the Allergy Diary was compared with EQ-5D (EuroQuol) and WPAI-AS (Work Productivity and Activity Impairment in allergy) in 1288 users in 18 countries. This study showed that quality-of-life data (EQ-5D visual analogue scale and WPA-IS Question 9) are similar in users without rhinitis and in those with mild rhinitis (scores 0-2). Users with a score of 3 or 4 had a significant impairment in quality-of-life questionnaires.

Use of emollients and topical glucocorticoids among adolescents with eczema: data from the population-based birth cohort BAMSE.

BACKGROUND: Knowledge regarding how adolescents treat their eczema is sparse. OBJECTIVES: To explore the use of emollients and topical glucocorticoids in adolescents with eczema in relation to sex and disease severity, and to study dispensing patterns of topical glucocorticoids. METHODS: Questionnaire-based data on symptoms of eczema, eczema severity and treatment with emollients and topical glucocorticoids were obtained from 3108 adolescents in the Swedish population-based birth cohort BAMSE. Severity of reported eczema was evaluated with the BAMSE Eczema Severity Score (BESS) in a questionnaire and with the Patient-Oriented Eczema Measure in clinically examined patients with current eczema (n = 247). Information on dispensed topical glucocorticoids was obtained from the Swedish Prescribed Drug Register. RESULTS: In all, 10% of the adolescents reported eczema in the preceding year: 73% mild, 17% moderate and 10% severe according to BESS. Almost all used emollients, whereas use of topical glucocorticoids was reported by 55%, with no significant difference between sexes. The likelihood of treatment with emollients and topical glucocorticoids increased when the adolescents had symptoms of current eczema [adjusted odds ratio (OR) 5·95, 95% confidence interval (CI) 1·90-18·8], but not if they had more severe eczema compared with mild eczema (adjusted OR 1·57, 95% CI 0·58-4·25). Among those with reported eczema, 24% had a topical glucocorticoid dispensed in the preceding year, and among those with moderate-to-severe current eczema 24% had a dispensed potent topical glucocorticoid. CONCLUSIONS: This population-based study indicates that adolescents with eczema are undertreated or completely untreated, even those with severe eczema.

Dietary total antioxidant capacity in early school age and subsequent allergic disease.

BACKGROUND: Dietary antioxidant intake has been hypothesized to influence the development of allergic diseases; however, few prospective studies have investigated this association. OBJECTIVE: Our aim was to study the association between total antioxidant capacity (TAC) of the diet at age 8 years and the subsequent development of asthma, rhinitis and sensitization to inhalant allergens between 8 and 16 years, and to assess potential effect modification by known risk factors. METHODS: A total of 2359 children from the Swedish birth cohort BAMSE were included. Dietary TAC at age 8 years was estimated by combining information on the child's diet the past 12 months from a food frequency questionnaire with a database of common foods analysed with the oxygen radical absorbance capacity method. Classification of asthma and rhinitis was based on questionnaires, and serum IgE antibodies were measured at 8 and 16 years. RESULTS: A statistically significant inverse association was observed between TAC of the diet and incident sensitization to inhalant allergens (adjusted odds ratio: 0.73, 95% confidence interval: 0.55-0.97 for the third compared to the first tertile, P-value for trend = 0.031). Effect modification by traffic-related air pollution exposure was observed, with a stronger association between dietary TAC and sensitization among children with low traffic-related air pollution exposure (P-value for interaction = 0.029). There was no evidence for effect modification by GSTP1 or TNF genotypes, although these results should be interpreted with caution. No clear associations were observed between TAC and development of rhinitis or asthma, although a significant inverse association was observed for allergic asthma (ORadj 0.57, 95% CI 0.34-0.94). CONCLUSIONS AND CLINICAL RELEVANCE: Higher TAC of the diet in early school age may decrease the risk of developing sensitization to inhalant allergens from childhood to adolescence. These findings indicate that implementing an antioxidant-rich diet in childhood may contribute to the prevention of allergic disease.

Mold and dampness exposure and allergic outcomes from birth to adolescence: data from the BAMSE cohort.

BACKGROUND: Exposure to moldy or damp indoor environments is associated with allergic disease in young children, but it is unclear whether the effects persist to adolescence. Our objective was to assess whether exposure to mold or dampness during infancy increases the risk of asthma, rhinitis, or IgE sensitization in children followed from birth to 16 years of age. METHODS: We collected questionnaire derived reports of mold or dampness indicators and allergic outcomes from 3798 children in a Swedish birth cohort (BAMSE). Sensitization was assessed from blood samples in 3293 children. Longitudinal associations between prevalent asthma, rhinitis, and IgE sensitization and mold or dampness indicators were assessed using generalized estimating equations. RESULTS: Exposure to any mold or dampness indicator was associated with asthma up to 16 years of age (OR 1.31; 95% CI 1.08-1.59), while exposure to mold odor (OR 1.29; 95% CI 1.03-1.62) and visible mold (OR 1.28; 95% CI 1.04-1.58) were associated with rhinitis. Increased risks were observed for nonallergic asthma (OR 1.80; 95% CI 1.27-2.55) and rhinitis (OR 1.41; 95% CI 1.03-1.93). No association was observed between mold or dampness indicators and IgE sensitization. Exposure to any mold or dampness indicator was associated with persistent asthma (OR 1.73; 95% CI 1.20-2.50), but not with early-transient or late-onset asthma. CONCLUSION: Exposure to mold or dampness during infancy increased the risk of asthma and rhinitis up to 16 years of age, particularly for nonallergic disease. Early exposure to mold or dampness appeared particularly associated with persistent asthma through adolescence.

Anaphylaxis to foods in a population of adolescents: incidence, characteristics and associated risks.

BACKGROUND: Information about severe reactions to foods in adolescence is limited. OBJECTIVE: To describe reactions to foods, including anaphylaxis, with regard to incidence, characteristics and associated risks, among 16-year-olds (adolescents) in a large, population-based birth cohort. METHODS: Parent-reported questionnaire data from ages 2-3 months, and 1, 2 and 16 years were used (N = 3153). Anaphylaxis at age 16 years was defined per NIAID/FAAN criteria. Immunoglobulin E (IgE) antibodies to 14 common food and inhalant allergens were analysed at ages 4 (n = 2283) and 16 years (n = 2510). Among adolescents with food-related symptoms (FRS) and for whom blood was available (n = 221), 25 additional food allergen extracts or allergen components were analysed. Associations between reactions to foods, and sensitization and allergic multimorbidity were investigated. RESULTS: In the 12 months prior to the 16-year assessment, 8.5% of adolescents had FRS. This included 0.8% (n = 24) adolescents who were classified as having anaphylaxis, yielding an incidence rate of 761/100 000 person-years. One-third of adolescents accessed health care during anaphylaxis. Allergic multimorbidity in infancy, as well as sensitization to foods and airborne allergens at age 4 years, was associated with an increased risk for FRS in adolescence. Peanuts and tree nuts were the most common culprit foods for anaphylaxis, and fruits and vegetables for non-anaphylactic reactions. Adolescents with anaphylaxis were significantly more likely to be sensitized to storage proteins (Ara h 2, Cor a 9, Cor a 14) and to be polysensitized to foods (P < 0.001 vs. non-anaphylactic reactions). CONCLUSIONS AND CLINICAL RELEVANCE: The incidence of food-induced anaphylaxis during adolescence in our population-based birth cohort is higher than previously reported. Adolescents with anaphylaxis differ from adolescents with non-anaphylactic FRS with regard to culprit foods and sensitization. Adolescents with previous anaphylaxis are likely to be polysensitized to foods, particularly tree nut and peanut storage proteins, and which warrants consideration at follow-up.

IgE antibodies in relation to prevalence and multimorbidity of eczema, asthma, and rhinitis from birth to adolescence.

BACKGROUND: Eczema, asthma, and rhinitis affect a large proportion of children, but their prevalence varies with age. IgE antibodies are also common in the pediatric population. However, the links between IgE, disease, and trajectories are unclear. OBJECTIVE: To better understand the links between sensitization and disease, we studied IgE sensitization ever in relation to eczema, asthma, and rhinitis, in children followed up to 16 years of age. METHODS: From the Swedish population-based birth cohort BAMSE, 2607 children were included. Parental reports from six time points between 1 and 16 years were used to identify children with eczema, asthma, and rhinitis. Blood was collected at 4, 8, and 16 years, and sensitization ever was defined as allergen-specific IgE ≥0.35 kUA /l to common food and/or inhalant allergens at any time point. Odds ratios for eczema, asthma, rhinitis, and multimorbidity in relation to sensitization ever were calculated using generalized estimating equations. RESULTS: Fifty-one percent were sensitized at least once up to 16 years. Almost a quarter of ever-sensitized children did not have any disease. After adjustment for potential confounders, sensitization ever was significantly associated with the following: (i) eczema throughout childhood, (ii) multimorbidity of eczema, asthma, and rhinitis from 1 to 16 years (OR for multimorbidity: 5.11, 95% CI: 3.99-6.55), (iii) asthma and rhinitis from 4 to 16 years of age. CONCLUSIONS: Specific IgE is strongly associated with eczema and allergic multimorbidity throughout childhood and with asthma and rhinitis from age 4 years. However, 23% of the children with IgE sensitization do not develop any disease in childhood.

Parental smoking and development of allergic sensitization from birth to adolescence.

BACKGROUND: The relation between secondhand tobacco smoke (SHS) exposure and the development of allergic sensitization in children is unclear. The aim of this study was to determine whether maternal smoking during pregnancy and postnatal SHS exposure contributes to the development of allergic sensitization in children and adolescents up to 16 years of age. METHODS: We included 3316 children from a birth cohort followed up for 16 years. SHS exposure and symptoms of allergic disease were assessed using repeated parental questionnaires. Serum immunoglobulin E against eight common inhalant and six food allergens was assessed at ages 4, 8, and 16 years with ImmunoCAP. The association between SHS exposure and sensitization was explored using logistic regression and generalized estimating equations. RESULTS: Exposure to SHS in infancy without prior exposure in utero was associated with an excess risk of food sensitization at age 4 years (OR 1.47, 95% CI 1.08-2.00), with comparable ORs at ages 8 and 16 years. In longitudinal analyses, an overall association was indicated between SHS in infancy and food sensitization up to age 16 years (OR 1.24, 95% CI 0.98-1.56). Maternal smoking during pregnancy was unrelated to sensitization up to 16 years of age. When sensitization was combined with concurrent symptoms of allergic disease, SHS in infancy was associated with an overall elevated risk of eczema with sensitization (OR 1.62, 95% CI 1.20-2.18). CONCLUSIONS: SHS exposure in infancy appears to increase the risk of sensitization to food allergens up to age 16 years, as well as eczema in combination with sensitization.

Residential greenness is differentially associated with childhood allergic rhinitis and aeroallergen sensitization in seven birth cohorts.

BACKGROUND: The prevalence of allergic rhinitis is high, but the role of environmental factors remains unclear. We examined cohort-specific and combined associations of residential greenness with allergic rhinitis and aeroallergen sensitization based on individual data from Swedish (BAMSE), Australian (MACS), Dutch (PIAMA), Canadian (CAPPS and SAGE), and German (GINIplus and LISAplus) birth cohorts (n = 13 016). METHODS: Allergic rhinitis (doctor diagnosis/symptoms) and aeroallergen sensitization were assessed in children aged 6-8 years in six cohorts and 10-12 years in five cohorts. Residential greenness was defined as the mean Normalized Difference Vegetation Index (NDVI) in a 500-m buffer around the home address at the time of health assessment. Cohort-specific associations per 0.2 unit increase in NDVI were assessed using logistic regression models and combined in a random-effects meta-analysis. RESULTS: Greenness in a 500-m buffer was positively associated with allergic rhinitis at 6-8 years in BAMSE (odds ratio = 1.42, 95% confidence interval [1.13, 1.79]) and GINI/LISA South (1.69 [1.19, 2.41]) but inversely associated in GINI/LISA North (0.61 [0.36, 1.01]) and PIAMA (0.67 [0.47, 0.95]). Effect estimates in CAPPS and SAGE were also conflicting but not significant (0.63 [0.32, 1.24] and 1.31 [0.81, 2.12], respectively). All meta-analyses were nonsignificant. Results were similar for aeroallergen sensitization at 6-8 years and both outcomes at 10-12 years. Stratification by NO2 concentrations, population density, an urban vs rural marker, and moving did not reveal consistent trends within subgroups. CONCLUSION: Although residential greenness appears to be associated with childhood allergic rhinitis and aeroallergen sensitization, the effect direction varies by location.

Paving the way of systems biology and precision medicine in allergic diseases: the MeDALL success story: Mechanisms of the Development of ALLergy; EU FP7-CP-IP; Project No: 261357; 2010-2015.

MeDALL (Mechanisms of the Development of ALLergy; EU FP7-CP-IP; Project No: 261357; 2010-2015) has proposed an innovative approach to develop early indicators for the prediction, diagnosis, prevention and targets for therapy. MeDALL has linked epidemiological, clinical and basic research using a stepwise, large-scale and integrative approach: MeDALL data of precisely phenotyped children followed in 14 birth cohorts spread across Europe were combined with systems biology (omics, IgE measurement using microarrays) and environmental data. Multimorbidity in the same child is more common than expected by chance alone, suggesting that these diseases share causal mechanisms irrespective of IgE sensitization. IgE sensitization should be considered differently in monosensitized and polysensitized individuals. Allergic multimorbidities and IgE polysensitization are often associated with the persistence or severity of allergic diseases. Environmental exposures are relevant for the development of allergy-related diseases. To complement the population-based studies in children, MeDALL included mechanistic experimental animal studies and in vitro studies in humans. The integration of multimorbidities and polysensitization has resulted in a new classification framework of allergic diseases that could help to improve the understanding of genetic and epigenetic mechanisms of allergy as well as to better manage allergic diseases. Ethics and gender were considered. MeDALL has deployed translational activities within the EU agenda.

Maternal body mass index in early pregnancy and offspring asthma, rhinitis and eczema up to 16 years of age.

BACKGROUND: Maternal obesity has been linked to offspring asthma; however, other allergy-related diseases, as well as the association beyond early school age, are largely unstudied. OBJECTIVE: To examine the associations between maternal body mass index (BMI) in pregnancy and offspring asthma, rhinitis, eczema and sensitization up to 16 years of age. METHODS: A total of 3294 children from the Swedish birth cohort BAMSE were included in the analyses. Maternal BMI was assessed around week 10 in pregnancy. Information on asthma, rhinitis, eczema, lifestyle factors and environmental exposures was obtained by parental questionnaires at 1, 2, 4, 8, 12 and 16 years. Sensitization was defined from IgE levels of inhalant allergens at 4, 8 and 16 years in a subsample of 2850 children. Generalized estimated equation models were used to analyse the associations between maternal BMI and the outcomes at 1-16 years. RESULTS: Maternal BMI was positively associated with overall risk of asthma up to age of 16 years (adj OR per 5 kg/m(2) increase: 1.23; 95% CI 1.07-1.40 for prevalent asthma) excluding underweight mothers. In contrast, no significant associations were found for rhinitis, eczema or sensitization. The association with asthma was restricted to obese, rather than overweight mothers, but was attenuated when adjusting for overweight in the offspring. A causal inference test at 16 years further indicated that the child's own overweight is a mediator in the suggested association between maternal BMI and offspring asthma at 16 years. CONCLUSIONS AND CLINICAL RELEVANCE: Maternal BMI is associated with an increased risk of asthma, but not rhinitis, eczema or sensitization; however, overweight in the offspring seems to have a mediating role. Prevention strategies of maternal pre-pregnancy and childhood obesity might be important to reduce the prevalence of childhood asthma.

Asthma phenotypes and lung function up to 16 years of age-the BAMSE cohort.

BACKGROUND: Asthma is a disease affecting many locations throughout the airway. Most studies have used spirometry as the primary assessment of airway obstruction, a method that may be less sensitive in regard to peripheral airway obstruction. The aim of this study was to elucidate the associations between asthma phenotypes based on age of onset and duration of symptoms, and (i) spirometry and (ii) small airway involvement measured by impulse oscillometry (IOS) in adolescence. METHODS: Children and adolescents taking part in BAMSE, a prospective birth cohort study, performed spirometry at 8 and 16 years and IOS at 16 years of age. Based on data collected in questionnaires, children were categorized into the following groups: 'never asthma', 'early transient asthma', 'early persistent asthma', and 'late onset asthma'. RESULTS: Compared with the never asthma group, all asthma groups were associated with lower FEV1 at 16 years of age (early transient-119 ml, 95% confidence interval -204 to -34; early persistent-410 ml, 95%CI -533; -287; and late onset-148 ml, 95%CI -237; -58). Between 8 and 16 years, significantly less increase in FEV1 was observed in the early persistent and late onset groups. The small airway index 'R5-20 ' was significantly associated with active asthma at 16 years, but not transient asthma. CONCLUSIONS: All asthma phenotypes studied were negatively associated with FEV1 in adolescence. IOS measurements indicated that active asthma could be associated with small airway impairments. These results provide new insights into the physiology underlying wheezing phenotypes based on age of onset and duration of disease.

Early-life house dust mite allergens, childhood mite sensitization, and respiratory outcomes.

BACKGROUND: Exposure to indoor allergens during early life may play a role in the development of the immune system and inception of asthma. OBJECTIVE: To describe the house dust mite (HDM) allergen concentrations in bedroom dust during early life and to evaluate its associations with HDM sensitization, wheezing, and asthma, from birth to school age, in 5 geographically spread European birth cohorts. METHODS: We included 4334 children from INMA-Menorca (Spain), BAMSE (Sweden), LISAplus and MAS (Germany), and PIAMA-NHS (the Netherlands). Dust samples were collected from bedrooms during early life and analyzed for Dermatophagoides pteronyssinus (Der p1) and Dermatophagoides farinae (Der f1). HDM concentrations were divided into four categories. Sensitization was determined by specific IgE. Wheezing and asthma information up to 8/10 years was collected through questionnaires. We performed mixed-effects logistic regression models and expressed associations as odds ratios with 95% confidence intervals. RESULTS: House dust mite concentrations varied across cohorts. Mean allergen concentrations were highest in INMA-Menorca (geometric mean (GM) Der p1 = 3.3 µg/g) and LISAplus (GM Der f1 = 2.1 µg/g) and lowest in BAMSE (GM Der p1 = 0.1 µg/g, Der f1 = 0.3 µg/g). Moderate and high HDM concentrations were significantly (P-values < 0.05) associated with 50-90% higher prevalence of HDM sensitization. No significant associations were observed with respiratory outcomes. CONCLUSION: Our study based on geographically spread regions, a large sample size, and a wide range of allergen concentration shows that HDM allergen concentrations vary across regions and that exposure during early life plays a role in the development of allergic sensitization but not in the development of respiratory outcomes.

Phenotyping asthma, rhinitis and eczema in MeDALL population-based birth cohorts: an allergic comorbidity cluster.

BACKGROUND: Asthma, rhinitis and eczema often co-occur in children, but their interrelationships at the population level have been poorly addressed. We assessed co-occurrence of childhood asthma, rhinitis and eczema using unsupervised statistical techniques. METHODS: We included 17 209 children at 4 years and 14 585 at 8 years from seven European population-based birth cohorts (MeDALL project). At each age period, children were grouped, using partitioning cluster analysis, according to the distribution of 23 variables covering symptoms 'ever' and 'in the last 12 months', doctor diagnosis, age of onset and treatments of asthma, rhinitis and eczema; immunoglobulin E sensitization; weight; and height. We tested the sensitivity of our estimates to subject and variable selections, and to different statistical approaches, including latent class analysis and self-organizing maps. RESULTS: Two groups were identified as the optimal way to cluster the data at both age periods and in all sensitivity analyses. The first (reference) group at 4 and 8 years (including 70% and 79% of children, respectively) was characterized by a low prevalence of symptoms and sensitization, whereas the second (symptomatic) group exhibited more frequent symptoms and sensitization. Ninety-nine percentage of children with comorbidities (co-occurrence of asthma, rhinitis and/or eczema) were included in the symptomatic group at both ages. The children's characteristics in both groups were consistent in all sensitivity analyses. CONCLUSION: At 4 and 8 years, at the population level, asthma, rhinitis and eczema can be classified together as an allergic comorbidity cluster. Future research including time-repeated assessments and biological data will help understanding the interrelationships between these diseases.

Atopic and nonatopic eczema in adolescence: is there a difference?

BACKGROUND: There is limited information on clinical manifestations of atopic eczema (AE) and non-AE in teenagers. OBJECTIVES: To describe the characteristics of adolescent eczema in the general population and to identify potential differences between AE and non-AE in teenagers. METHODS: Overall, 3108 teenagers were included from the population-based BAMSE cohort and 2529 of these teenagers provided blood samples for analysis of specific IgE. At age 16 years, the teenagers answered questionnaires regarding the symptoms of eczema, asthma and rhinitis for the previous year. RESULTS: The prevalence of eczema in adolescence was 9·6% (n = 297). More girls than boys had eczema (12·5% vs. 6·5%; P < 0·001). The age at onset was usually within the first 2 years of life (48·8%), but onset in adolescence was also common (25·6%). Eczema was mild in 72·7% of cases, moderate in 16·8% and severe in 10·4%. Body folds were most frequently affected (73·4%). More than half of the teenagers with eczema had AE (59%). The teenagers with AE had more severe and more chronic eczema. Onset in infancy was most common in AE and onset in adolescence was most common in non-AE. There were no major differences in location or seasonal variance between AE and non-AE in adolescence. CONCLUSIONS: AE is more common than non-AE among teenagers. More than one in four teenagers with eczema has moderate-to-severe disease. Onset in adolescence is common, especially for non-AE. AE in adolescence has an earlier onset and is more chronic and more severe than non-AE.