Temporal trends of aeroallergen sensitization over twenty-five years

BACKGROUND: Little is known about time trends of allergic respiratory disease in adults, in particular in older adults. Furthermore, few trend studies have used objective measurements of IgE sensitization against inhalant allergens. OBJECTIVES: To investigate time trends of aeroallergen sensitization in adults over a 25-year period. METHODS: The study includes a total of 7820 persons, aged 30, 40, 50, and 60 years, who participated in three repeated cross-sectional studies of the general population of Copenhagen, Denmark, in 1976-1977, 1982-1984, and 1999-2001, respectively. Respiratory allergy was assessed by determination of specific IgE aeroallergen sensitization in stored serum samples. RESULTS: Over this 25-year period, a marked and statistically significant increase in the prevalence of aeroallergen sensitization had occurred. This increase was seen in all age-groups challenging the notion that the allergy epidemic only affects generations born 1960 onwards. For example, in 40-year-olds the prevalence (with 95% confidence intervals) of aeroallergen sensitization was 14.9% (12.7-17.1), 19.7% (17.1-22.3), and 27.6% (25.1-30.1) in 1976-1977, 1982-1984, and 1999-2001, respectively. CONCLUSIONS: Our results support that the allergy epidemic has spread to older adults resulting in a continuing increase in the overall prevalence of aeroallergen sensitization and an increase in the mean age of allergic patients.     

An association between plastic mattress covers and sheepskin underbedding use in infancy and house dust mite sensitization in childhood: a prospective study

BACKGROUND: Higher house dust mite (HDM) allergen exposure during infancy has been associated with increased HDM sensitization. Infant bedding has been associated with the accumulation of varying levels of HDM. Prospective data on the relationship between infant bedding and the development of HDM sensitization has not been previously examined. OBJECTIVES: To determine if particular types of bedding used in infancy are associated with increased risk of house dust mite sensitization in childhood. METHODS: A population-based sample (n = 498) of children born in 1988 or 1989, and who were resident in Northern Tasmania in 1997, participated in this study. These children were part of a birth cohort study (1988-95), the Tasmanian Infant Health Survey. Data on infant underbedding and mattresses was available on 460 and 457 children, respectively. The main outcome measure was HDM sensitization defined as a skin prick test (SPT) reaction of 3 mm or more to the allergens of Dermatophagoides pteronyssinus and/or Dermatophagoides farinae. RESULTS: The use of either sheepskin underbedding or plastic mattress covers in infancy was associated with an increased risk of sensitization to HDM allergens at age 8 years. The adjusted risk ratio (RR) for sensitization to HDM with sheepskin in infancy was 2.27 (95% CI: 1.14, 4.55), P = 0.020. The adjusted RR for sensitization to HDM with the use of plastic mattress covers in infancy was 2.06 (95% CI: 1.22, 3.51), P = 0.007. The use of a foam mattress in infancy was not related to subsequent HDM sensitization. CONCLUSION: Infant's bedding plays a role in the development of HDM sensitization in childhood. Intervention studies to examine mite allergen levels and the role of underbedding on the development of HDM sensitization are required.     

Association between alcohol consumption and aeroallergen sensitization in Danish adults

BACKGROUND: It has been proposed that alcohol consumption may be one of the lifestyle factors associated with a westernized, urban, and affluent lifestyle contributing to the rise in atopic disease. OBJECTIVE: The aim was to investigate the association between alcohol consumption and atopy (aeroallergen sensitization). METHODS: In 1982, a population-based cross-sectional study of 3608 Danes (79% of the invited), aged 30, 40, 50, and 60 years, was carried out. Information on alcohol consumption was obtained by a questionnaire. Aeroallergen sensitization was defined as a positive test for the detection of specific IgE against a panel of 19 common inhalant allergens in stored serum samples. A total of 3317 subjects with complete information on all variables were included in the analyses. RESULTS: We found a statistically significant association between alcohol consumption and aeroallergen sensitization (independent of the type of alcoholic drink consumed). This association appeared to relate only to those who consumed more than 8 drinks/week. After adjustment for confounders this association was only statistically significant for those who consumed 15-21 drinks/week (adjusted odds ratio 1.8, 95% confidence interval 1.2-2.8). CONCLUSION: In this adult general population, self-reported alcohol consumption was positively associated with aeroallergen sensitization.     

Mucosal bromodomain-containing protein 4 mediates aeroallergen-induced inflammation and remodeling

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Outdoor fungi and child asthma health service attendances

Asthma is a significant global public health issue. Severe asthma exacerbations can be triggered by environmental factors and require medical care from health services. Although it is known that fungal exposure may lead to allergic sensitization, little is understood about its impact on asthma exacerbations. This review aims to examine whether outdoor fungi play a significant role in child asthma exacerbations. Systematic search of seven electronic databases and hand searching for peer‐reviewed studies published in English, up to 31 August 2013. Inclusion criteria were study population aged <18 yr, diagnosis of asthma, attended a health service; outdoor fungi exposure was reported. Quality and risk of bias assessments were conducted. Due to significant heterogeneity, meta‐analysis was not conducted. Of the 1896 articles found, 15 were eligible. Findings were not consistent, possibly due to methodological variations in exposure classifications, statistical methods and inclusion of confounders. Cross‐sectional studies found no or weak associations. All but one time series studies indicated an association that varied between fungal species. Increasing evidence indicates that asthmatic children are susceptible to asthma exacerbations when exposed to outdoor fungal spores. There is limited understanding of the contributions of different fungal species. Research is needed to investigate interactions of outdoor fungi with pollen, air pollutants and respiratory viruses.     

Repeated latex aeroallergen challenges employing a hooded exposure chamber: safety and reproducibility

BACKGROUND: Bronchial, nasal, and conjunctival challenges are useful for clarifying discordant clinical history (Hx) and skin and/or serologic tests and in assessing semiquantitative changes in biologic sensitivity over time. The objective of this study was to determine the safety and reproducibility of repeated latex-allergen challenges with a hooded exposure chamber (HEC). METHODS: The HEC system comprises a powered forced-air respirator with a fitted face shield and hood that uses glove-derived latex-allergen associated cornstarch particles (LAC) to expose simultaneously the conjunctiva, nose, and lungs. Serial control and incremental LAC challenges are conducted until an endpoint based on upper and/or lower respiratory tract symptoms and peak expiratory flow rates is reached. Six latex-allergic (Hx and puncture skin test [PST]- and 5/6 radioallergosorbent test [RAST]-positive) subjects were challenged on three separate occasions at least 2 weeks apart. Serial latex PST midpoints and serum anti-latex IgE by RAST were monitored at each visit and at a fourth follow-up visit. RESULTS: All subjects responded to LAC, but not to air or control cornstarch administered as controls. All responses were confined to mild symptoms of allergic rhinoconjunctivitis and/or asthma that either resolved spontaneously or were reversed with inhaled albuterol. No subject experienced a systemic or delayed reaction. There were no significant changes in the endpoint LAC doses over the three challenge visits (P>0.2). The mean coefficient of variation for log2 endpoints within-subjects was 17.3+/-17.2% (SD). The serum latex-specific IgE was not significantly boosted by the three challenges (P>0.2). The concentration of latex extract necessary to produce an 8-mm wheal by PST was not significantly changed during the study (P>0.1), indicating that latex sensitivity was not affected by the repeated LAC exposures. CONCLUSIONS: The results of this study indicate that repeated HEC latex-allergen challenges are both reproducible and safe, and do not increase latex sensitivity.     

Increase in atopic sensitization rate among Dutch children with symptoms of allergic disease between 1994 and 2014

Background

The prevalence of symptoms of allergic diseases has increased significantly during the last decades. However, studies into time trends of atopic sensitization among children are limited and have focused on aeroallergen sensitization. We aimed to investigate time trends in the prevalence and degree of atopic sensitization to inhalant and food allergens among children (0‐17 years) with symptoms of allergic disease.

Methods

Sensitization data of all children tested in our clinical laboratory during 1994‐2014 were analyzed. Sensitization was detected using the ImmunoCAP system and defined as a specific IgE level of ≥0.35 kU/L. Trends in sensitization rates to 5 food and 5 aeroallergens for different age categories were investigated with logistic regression, adjusted for age and sex.

Results

Sensitization data of 18 199 children were analyzed. Between 1994 and 2014, a steady and statistically significant increase in overall sensitization rate was found (from 40.5% in 1994 to 48.9% in 2014, adjusted odds ratio [aOR] 1.01 per year, 95% confidence interval [CI] 1.00 to 1.01, P = .003). This increase in sensitization rate was mainly explained by increasing aeroallergen sensitization among 4‐ to 11‐year‐old children (aOR 1.02, 95% CI 1.01 to 1.02, P < .001). We found no increase in sensitization rates to food and aeroallergens in other age categories. The degree of sensitization did not change significantly during the study period (all tests P > .15).

Conclusion

We observed a statistically significant increase in sensitization rate between 1994 and 2014 among children with symptoms of allergic disease. This was mainly explained by increasing aeroallergen sensitization among 4‐ to 11‐year‐olds.     

Association of obesity and insulin resistance with asthma and aeroallergen sensitization

Background:  It has been hypothesized that obesity and insulin resistance may play a role in the development of asthma and allergy. The aim of the study was to examine the association of obesity and insulin resistance with asthma and aeroallergen sensitization.
Methods:  Cross-sectional population-based study of 3609 Danish men and women aged 30–60 years. Aeroallergen sensitization was defined as positive levels of specific IgE against a panel of inhalant allergens. Asthma was defined as self-reported physician diagnosed asthma. Allergic asthma was defined as the presence of both asthma and aeroallergen sensitization. The homeostasis model assessment of insulin resistance was used to estimate the degree of insulin resistance. Body mass index, waist-to-hip ratio, and waist circumference were used as measures of obesity. Data were analyzed by multiple logistic regression analyses.
Results:  Obesity was associated with increased risk of aeroallergen sensitization as well as allergic and nonallergic asthma. Insulin resistance was asssociated with aeroallergen sensitization and allergic asthma, but not nonallergic asthma. The associations of obesity with aeroallegen sensitization and allergic asthma became nonsignificant after adjustment for insulin resistance, whereas the association of obesity with nonallergic asthma was unaffected. No sex-differences were observed.
Conclusion:  Obesity may be related to an increased risk of aeroallergen sensitization and allergic asthma through mechanisms also involved in the development of insulin resistance.