Changes in lung function due to childhood asthma have been reported to occur before school age, and to persist throughout life. The aim was to assess the relationship between aspects of lung function and asthma over time in 4,089 children participating in the large population-based birth cohort BAMSE. Questionnaires were administered at 1, 2, 4, and 8 years of age. At 4 and 8 years, children were invited to a clinical examination, in which 2,965 and 2,630 children participated, respectively. The examinations included blood sampling for evaluation of sensitization to airway allergens (n = 2,053), peak expiratory flow (PEF) measurements at 4 and 8 years (n = 1,957), and forced expiratory flows (n = 2,455) at 8 years. Asthma onset before the age of 4 years, but no thereafter, was at 8 years associated with impaired spirometric flows. This was seen irrespective of symptom presence after the age of 4. Reduced PEF growth between the age of 4 and 8 was seen only for the group of children with early onset transient asthma, while an association between sensitization and lung function was only seen in the late-onset asthma group. In conclusion, school children with asthma have reductions of spirometric flows when categorized as persistent or transient early onset asthma, even if this latter group of children is completely symptom-free at school age.
"Many studies have identified allergic sensitisation (in particular to inhalant allergens) as a strong associate of lung function[1-8] and airway hyperresponsiveness[7-13], both in children and in adults, with reduced lung function and increased airway hyperresponsiveness in sensitised compared to non-sensitised individuals. However, as outlined previously, most such studies have considered sensitisation as either present or not[1-5,8-11]. A previous study by Burrows and colleagues investigated the associates of AHR in children, looking at the sizes of skin test wheals when analysing atopy, and demonstrated that the sizes of the reactions to mite, cat, dog and Aspergillus fumigatus were independently correlated with airway hyperresponsiveness, particularly when summed. "
[Show abstract][Hide abstract] ABSTRACT: Studies in children have shown that concentration of specific serum IgE (sIgE) and size of skin tests to inhalant allergens better predict wheezing and reduced lung function than the information on presence or absence of atopy. However, very few studies in adults have investigated the relationship of quantitative atopy with lung function and airway hyperresponsiveness (AHR).
To determine the association between lung function and AHR and quantitative atopy in a large sample of adults from the UK.
FEV1 and FVC (% predicted) were measured using spirometry and airway responsiveness by methacholine challenge (5-breath dosimeter protocol) in 983 subjects (random sample of 800 parents of children enrolled in a population-based birth cohort enriched with 183 patients with physician-diagnosed asthma). Atopic status was assessed by skin prick tests (SPT) and measurement of sIgE (common inhalant allergens). We also measured indoor allergen exposure in subjects' homes.
Spirometry was completed by 792 subjects and 626 underwent methacholine challenge, with 100 (16.0%) having AHR (dose-response slope>25). Using sIgE as a continuous variable in a multiple linear regression analysis, we found that increasing levels of sIgE to mite, cat and dog were significantly associated with lower FEV1 (mite p = 0.001, cat p = 0.0001, dog p = 2.95 × 10-8). Similar findings were observed when using the size of wheal on skin testing as a continuous variable, with significantly poorer lung function with increasing skin test size (mite p = 8.23 × 10-8, cat p = 3.93 × 10-10, dog p = 3.03 × 10-15, grass p = 2.95 × 10-9). The association between quantitative atopy with lung function and AHR remained unchanged when we repeated the analyses amongst subjects defined as sensitised using standard definitions (sIgE>0.35 kUa/l, SPT-3 mm>negative control).
In the studied population, lung function decreased and AHR increased with increasing sIgE levels or SPT wheal diameter to inhalant allergens, suggesting that atopy may not be a dichotomous outcome influencing lung function and AHR.
[Show abstract][Hide abstract] ABSTRACT: Background: Early wheezing and asthma are relevant health problems in the tropics. Mite sensitization is an important risk factor, but the roles of others, inherent in poverty, are unknown. We designed a birth-cohort study in Cartagena (Colombia) to investigate genetic and environmental risk factors for asthma and atopy, considering as particular features perennial exposure to mites, parasite infections and poor living conditions. Methods: Pregnant women representative of the low-income suburbs of the city were randomly screened for eligibility at delivery; 326 mother-infant pairs were included at baseline and biological samples were collected from birth to 24 months for immunological testing, molecular genetics and gene expression analysis. Pre and post-natal information was collected using questionnaires. Results: 94% of families were from the poorest communes of the city, 40% lacked sewage and 11% tap-water. Intestinal parasites were found as early as 3 months; by the second year, 37.9% of children have had parasites and 5.22% detectable eggs of Ascaris lumbricoides in stools (Median 3458 epg, IQR 975-9256). The prevalence of "wheezing ever" was 17.5% at 6 months, 31.1% at 12 months and 38.3% at 24 months; and recurrent wheezing (3 or more episodes) 7.1% at 12 months and 14.2% at 24 months. Maternal rhinitis [aOR 3.03 (95%CI 1.60-5.74), p = 0.001] and male gender [aOR 2.09 (95%CI 1.09 -4.01), p = 0.026], increased risk for wheezing at 6 months. At 24 months, maternal asthma was the main predisposing factor for wheezing [aOR 3.65 (95%CI 1.23-10.8), p = 0.01]. Clinical symptoms of milk/egg allergy or other food-induced allergies were scarce (1.8%) and no case of atopic eczema was observed. Conclusions: Wheezing is the most frequent phenotype during the first 24 months of life and is strongly associated with maternal asthma. At 24 months, the natural history of allergic symptoms is different to the "atopic march" described in some industrialized countries. This cohort is representative of socially deprived urban areas of underdeveloped tropical countries. The collection of biological samples, data on exposure and defined phenotypes, will contribute to understand the gene/environment interactions leading to allergy inception and evolution.
[Show abstract][Hide abstract] ABSTRACT: Allergy-related diseases are a public health issue, but knowledge on development and comorbidity among children is scarce. The aim was to study the development of eczema, asthma and rhinitis in relation to sex and parental allergy, in a population-based cohort, during childhood.
At 1, 2, 4, 8 and 12 years, parental questionnaires were used to obtain data on allergy-related diseases. Complete data for all five follow-up occasions were available from 2916 children. Odds ratios for the risk of any allergy-related disease in relation to heredity and sex were calculated using generalized estimating equations.
At 12 years, 58% of the children had had eczema, asthma and/or rhinitis at some time. Disease turnover was high for all three diseases throughout the study. Comorbidity increased with age, and at 12 years, 7.5% of all the children were affected by at least two allergy-related diseases. Parental allergy was associated with increased comorbidity and more persistent disease and increased the risk of having any allergy-related disease (adjusted OR 1.76; 95% CI 1.57-1.97) up to 12 years. Male sex was associated with an increased risk throughout childhood. Boys and girls did not differ in disease persistence, and for comorbidity, the differences were minor.
Allergy-related diseases may affect a majority of children. Eczema, asthma and rhinitis develop dynamically throughout childhood, and allergic comorbidity is common. These findings indicate that allergy-related diseases should be neither seen nor studied as isolated entities.
Maryam Bakhshandeh Bavarsad, Abdolali Shariati, Esmaeil Eidani, Mahmud Latifi
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