Project description:BACKGROUND:House dust endotoxin may have beneficial effects on allergic sensitization and asthma in children. Evidence is scarce for adolescents and most studies so far have been cross-sectional and limited to a single exposure measurement. OBJECTIVE:We assessed associations of house dust endotoxin with asthma and allergic sensitization from birth to age 17 years longitudinally taking into account exposure early in life and at primary school age. METHODS:We used data of 854 participants of the prospective Dutch PIAMA birth cohort study with house dust endotoxin measurements at 3 months and/or 5-6 years and data on asthma and/or allergic sensitization from at least one of 11 follow-ups until age 17. We assessed overall and age-specific associations of the prevalence of asthma and sensitization with mattress and living room floor dust concentrations (per gram of dust) and loads (per m2 of sampling surface). RESULTS:Higher living room floor dust endotoxin concentrations at 3 months were associated with lower odds of asthma until age 4 [odds ratio (95% confidence interval) ranging from 0.70 (0.51-0.97) at age 1 to 0.76 (0.57-1.00) at age 3 per interquartile range increase], but not thereafter in children of allergic mothers. Higher living room floor dust endotoxin at 5-6 years was associated with higher odds of sensitization at 8-16 years [eg odds ratio (95% confidence interval) 1.70 (1.17-2.47) per interquartile range increase in endotoxin load]. CONCLUSIONS AND CLINICAL RELEVANCE:House dust endotoxin may have beneficial effects on asthma in preschool children of allergic mothers, which do not persist into adolescence. Beneficial associations with allergic sensitization could not be confirmed.
Project description:BackgroundSpecific patterns of allergic sensitization as well as quantification of the in vitro IgE response in early life may provide relevant clinical insight into future rhinitis and asthma risk.ObjectiveTo define relationships among established sensitization to particular aeroallergens, quantitative analyses of allergen-specific IgE levels, pet exposure and sensitization, and asthma and rhinitis risk.MethodsChildren at high-risk for the development of asthma and allergic diseases were enrolled at birth into the Childhood Origins of ASThma (COAST) study. Allergen-specific IgE was assessed at ages 1, 3, 6, and 9 years by fluoroenzyme immunoassay (Unicap(®) 100; Pharmacia Diagnostics). Current asthma and rhinitis were diagnosed at age 6 and 8 years.ResultsSensitization to dog was strongly associated with increased asthma risk (P < 0.0001). Sensitization to perennial compared with seasonal allergens was more strongly associated with asthma risk, while sensitization to seasonal allergens was more closely associated with rhinitis risk. Increased levels of specific IgE to perennial allergens were associated with an increased asthma risk (P = 0.05), while any detectable level of IgE to seasonal allergens was associated with increased rhinitis risk (P = 0.0009). While dog and cat sensitization were both independently associated with increased asthma and rhinitis risk, dog exposure at birth was associated with a reduced risk of asthma, regardless of dog sensitization status during the first 6 years of life (P = 0.05).Conclusions and clinical relevanceAnalysing specific patterns of an individual's allergic sensitization profile reveals additional relevant associations with asthma and rhinitis risk as opposed to the information gained from characterizing an individual as 'atopic' by the presence of any demonstrable sensitization alone. Furthermore, protective mechanisms of dog exposure with regards to asthma risk appear to be unrelated to the prevention of sensitization.
Project description:BACKGROUND:Childhood asthma is an important public health problem worldwide. Risk factors for asthma development include allergic sensitization and exposure to animals. OBJECTIVE:To identify which (perennial or seasonal) inhalant allergens are associated with asthma and allergic rhinitis in children. METHODS:This was a cross-sectional, retrospective study. We evaluated data from medical documentation of 6,000 children (aged 6 - 18 years) with diagnosed asthma and/or allergic rhinitis who had attended our allergy outpatient clinic. Into the analyses we included those subjects who had specific IgE test done during diagnostic procedures to confirm allergen sensitization. RESULTS:We included 5,076 children in the analysis. We showed that among seasonal allergens only sensitization to timothy or birch significantly changed the prevalence of allergic rhinitis and asthma diagnosis. Of the perennial allergens, house dust mite or cat were most closely related with both allergic rhinitis and asthma. Results of ROC curve analysis showed that in atopic children the specific IgE level of seasonal allergens did not significantly change the prevalence of asthma diagnosis. Sensitization to more than one perennial allergen significantly increased the prevalence of allergic rhinitis and asthma. CONCLUSION:We showed that sensitization to the seasonal allergens timothy and birch as well as to the perennial allergens house dust mite and cat, is associated with asthma and allergic rhinitis in children. Our study determined the role of multiple perennial indoor allergens in the developement of allergic diseases in children. The identification of the specific allergens makes them potential targets for intervention and prevention strategies.
Project description:BackgroundDietary fibre may reduce the risk of allergy. Our aim was to investigate the association between fibre intake in childhood, asthma, allergic rhinitis and IgE sensitization up to adulthood.MethodsThe individual fibre intake of 2285 participants from the Swedish population-based birth cohort BAMSE was estimated between 98- and 107-item food frequency questionnaires at ages 8 and 16 years, respectively. At 8, 16 and 24 years, asthma and allergic rhinitis symptoms were assessed by questionnaires, and sensitization to common allergens by serum IgE. Longitudinal associations were analysed by generalized estimating equations, adjusting for potential confounders.ResultsAn inverse overall association was indicated between fibre intake at 8 years and allergic rhinitis symptoms up to 24 years (OR per 5 g/d 0.86; 95% CI 0.77-0.96), particularly in combination with airborne (0.74; 0.62-0.89) and food (0.69; 0.54-0.88) allergen sensitization. Higher fibre intake was also associated with specific allergen sensitization, for example, birch (0.77; 0.67-0.88) and soy (0.68; 0.53-0.87). No association was observed with asthma. Regarding sources, fruit (0.79; 0.67-0.94) and other (potatoes, chips/popcorn, legumes, and nuts, 0.71; 0.50-0.99), but not cereal or vegetable fibre were associated with allergic rhinitis. In additional analyses, including long-term fibre intake at 8 and 16 years, excluding participants with food-related allergic symptoms to examine reverse causation, as well as adjusting for antioxidant intake, associations were attenuated and became non-significant.ConclusionHigher fibre intake in mid-childhood may be inversely associated with allergic rhinitis and sensitization to specific allergens up to adulthood. However, avoidance of food triggers of allergic symptoms in allergic rhinitis patients may contribute to the protective associations.
Project description:Inappropriate responses to respiratory viruses, especially rhinovirus, and early allergic sensitization are the strongest contributors to the inception and persistence of early onset asthma. The ORMDL3 asthma locus in chromosome 17q seems to exert its effects by increasing susceptibility to human rhinovirus in early life. Being raised on animal farms is highly protective against the development of asthma, and this protective effect is mediated by exposure to microbes. Two trials in high-risk young children, one to prevent wheezing lower respiratory tract illness using bacterial lyophilizates and another using anti-immunoglobulin E to prevent asthma progression, are already under way.
Project description:BackgroundThe role of early-life vitamin D in childhood allergy is controversial.ObjectiveWe sought to assess vitamin D exposure in early life by multiple modalities and ascertain its association with childhood allergic rhinitis and allergic sensitization.MethodsOne thousand two hundred forty-eight mother-child pairs from a US prebirth cohort unselected for any disease were studied. Vitamin D exposure was assessed by measures of maternal intake during the first and second trimesters of pregnancy and serum 25-hydroxyvitamin D (25[OH]D) levels in mothers during pregnancy, cord blood, and children at school age (median age, 7.7 years; interquartile range, 1.0 years). Tests for associations between vitamin D exposure with ever allergic rhinitis, serum total IgE level, and allergen sensitization at school age were conducted.ResultsThe correlations between maternal intake of vitamin D during pregnancy and serum 25(OH)D levels in pregnant mothers, cord blood, and children at school age were weak to moderate (r = -0.03 to 0.53). Each 100 IU/d of food-based vitamin D intake during the first and second trimesters (equivalent to the amount of vitamin D in an 8-ounce serving of milk) was associated with 21% and 20% reduced odds of ever allergic rhinitis at school age (odds ratios of 0.79 [95% CI, 0.67-0.92] and 0.80 [95% CI, 0.68-0.93]), respectively. There were no associations between maternal supplemental vitamin D intake or serum 25(OH)D levels at any time point with ever allergic rhinitis. There were no associations between any vitamin D exposure and serum total IgE level or allergen sensitization at school age.ConclusionsInclusion of foods containing vitamin D in maternal diets during pregnancy may have beneficial effects on childhood allergic rhinitis.
Project description:BackgroundChildhood-onset allergic asthma is the best-known phenotype of asthma. Adult-onset asthma, also an important entity, is instead often shown to be more non-allergic. There is still a lack of studies concerning the association of allergies and age at asthma onset from childhood to late adulthood. The aim of the study was to assess the age at onset of asthma symptoms and age at asthma diagnosis among adults with allergic and non-allergic asthma.MethodsQuestionnaires were sent to 2000 randomly selected Finnish adults aged 18-80 years who were dispensed medication for obstructive airway diseases during the previous year. The corrected sample size was 1978 subjects after exclusion of non-analysable data. The response rate was 40.6%. Self-reported doctor-diagnosed asthma was considered allergic if a concomitant self-reported doctor-diagnosed pollen and/or animal allergy was reported with asthma symptoms upon allergen exposure.ResultsOf the 496 participants with asthma, 42.7% were considered to have allergic asthma. The median ages at asthma diagnosis and onset of asthma symptoms were 31 (IQR 17-46) and 20 (9.25-40) years in participants with allergic asthma and 49 (37.75-58) and 40.5 (30-50) years in participants with non-allergic asthma (p < 0.001), respectively. Of the participants with asthma diagnosed at ≥30 years of age, 18% of allergic and 7% of non-allergic participants reported having had asthma symptoms under 20 years of age.ConclusionsBoth the onset of symptoms and diagnosis occurred at a younger age among adults with allergic asthma than among those with non-allergic asthma. Only a minority of adults with non-allergic asthma had already had symptoms in younghood.
Project description:BACKGROUND:Despite its high prevalence, early onset and chronic nature, the causes of asthma are not clearly established. The present study examined a plausible but untested relationship in the development of non-allergic asthma; an asthma phenotype closely linked to deprivation and other preventable risk factors. Our aim was to determine the mediating role of adiposity in the relationship between socioeconomic position in infancy and non-allergic asthma emergence in mid-childhood. METHODS:To estimate the causal indirect effect of adiposity we applied the parametric g-computational procedure to 6203 singleton children from the UK Millennium Cohort Study. Adiposity was measured at age 7 by body mass index, waist circumference and waist circumference-to-height ratio. Children who developed non-allergic asthma between the age of 7 and 14 were compared with children without allergies or allergic asthma at these ages. RESULTS:We found no evidence to suggest that adiposity is a mediator in the relationship between socioeconomic position and the development of non-allergic asthma in mid-childhood. After adjustment for risk factors, the direct effect of socioeconomic position remained; children in the lowest tertile of socioeconomic position had a 43% (OR 1.43, 95%?CI 1.38 to 1.49) greater odds of developing non-allergic asthma compared with the highest tertile. CONCLUSIONS:Adiposity at age 7 does not mediate the relationship between socioeconomic position and non-allergic asthma. The results suggest that improving socioeconomic conditions and promoting healthy weight are both important in reducing the development of non-allergic asthma in early to mid-childhood.
Project description:BackgroundNon-communicable diseases, such as allergies, are influenced by both genetic and epigenetic factors. Perinatal determinants conceivably modify the epigenetic makeup of the developing fetal immune system preventing or predisposing the development of allergies. The aim of this study therefore was to identify independent perinatal factors associated with allergic sensitization in childhood.MethodsIn a single center retrospective case-cohort study electronic obstetric medical records and available skin prick testing results of children were analyzed. For the analysis 286 skin prick test positive (sensitized) children [median (IQR): 3.47 (1.70-7.34) years] were compared with data from all remaining live births in the obstetric cohort (n = 66,583).ResultsSensitized children more frequently had a mother born in Asia (19.1% vs. 10.2%; P < 10-6). Applying backward elimination logistic regression, seven out of 23 initially entered perinatal factors remained in the model. High maternal age (> 35 years; OR: 1.912; P < 0.001), male offspring sex (OR: 1.423; P < 0.01) and assisted conception (OR: 1.771; P < 0.05) increased the risk for allergic sensitization. In contrast, maternal smoking (OR: 0.469; P < 0.005), increasing parity (OR: 0.881; P < 0.05), maternal pre-pregnancy overweight (OR: 0.742; P < 0.005) and preterm birth (OR: 0.484; P < 0.05) decreased the risk for allergic sensitization.ConclusionsIn addition to supporting previous findings, this study is first to report an increased risk of allergic sensitization after assisted conception. Beyond this finding's potential implementation in preventative strategies, exploration of this association could further pathophysiological understanding of allergic disease.
Project description:BackgroundThe aim of this study was to examine if food and/or aeroallergen sensitization was associated with worse asthma, pulmonary function tests (PFT), and laboratory markers.MethodsAt our institution, 386 children with asthma were divided into allergic and nonallergic groups based on allergen-specific immunoglobulin E (IgE) testing classes 1-6 versus 0. Asthma severity and/or control, IgE level, eosinophil counts and/or percentages, forced vital capacity (FVC), forced expiratory volume in the first second of expiration (FEV1), and FEV1/FVC, were compared by using bivariate, regression, and subgroup analyses for children who were highly allergic (≥4 allergens).ResultsA total of 291 subjects with asthma were allergic, significantly older, and had higher mean IgE levels and eosinophil counts and percentages (all p < 0.001). A total of 203 subjects who were highly allergic had worse obstruction on PFTs. Increasing age predicted allergen sensitization after confounder adjustment, odds ratio (OR) 1.54 (95% confidence interval [CI], 1.18-2.02). Similarly, PFT obstruction was associated with multiple allergen sensitization (OR 0.97 [95% CI, 0.93-1.02]).ConclusionIncreasing age predicted allergic sensitization and multiple allergen sensitization. Worse obstruction on PFT also predicted multiple allergen sensitization. Continued surveillance of aeroallergen sensitization and PFT results may be beneficial in asthma management, particularly in older urban children.