Trends (2007-2019) of major atopic diseases throughout the life span in a large Mexican population

Background

Major atopic diseases such as atopic dermatitis (AD), allergic rhinitis (AR), and asthma share the same atopic background, but they often show differences in their epidemiological behavior.

Objective

We aimed to report the profile of these atopic diseases in a large Mexican population, including their age-related incidences, male:female (M:F) ratios, recent time trends, and association with altitude.

Methods

Registries from the largest, nationwide health institution in Mexico (more than 34 million insured subjects), were reviewed. New cases of AD, AR, and asthma diagnosed each year by family physicians from 2007 to 2019 were adjusted by the corresponding insured population to estimate incidence rates.

Results

Incidences of the 3 atopic diseases were highest in the 0-4 years age-group and progressively decreased thereafter until adolescence. Asthma and AR, but not AD, were more frequent in males during childhood (M:F ratios of 1.5, 1.3, and 0.95, respectively), but predominated in females during adulthood (M:F ratios of 0.52, 0.68, and 0.73, respectively). Time trends showed an initial increasing trend of annual incidences, with a peak around 2009-2011, and a downward trend afterward. This decreasing trend was seen in all age-groups and was more evident for AD (∼50% drop) and asthma (∼40% drop) than for AR (∼20% drop). Geographical distribution suggested that incidences of asthma and AR, but not of AD, had an inverse association with altitude.

Conclusion

Annual incidences of the 3 major atopic diseases have declined in recent years in almost all age groups, and their epidemiological profile during the life span showed contrasting differences according to age, sex, and ecological association with altitude, mainly regarding AD.

Eczema among adolescents in Kuwait: Prevalence, severity, sleep disturbance, antihistamine use, and risk factors

Background

Eczema (atopic dermatitis) is a common inflammatory skin disease that is more prevalent in children and adolescents than adults. In Kuwait, there is a lack of empirical knowledge on eczema epidemiology among adolescents. Therefore, this study aimed to estimate the prevalence of eczema symptoms and severity, assess the frequency of eczema-related nocturnal sleep disturbance and its relation to antihistamine use, and determine factors that are associated with eczema prevalence and eczema-related nocturnal sleep disturbance.

Methods

A school-based cross-sectional study enrolled adolescents (n = 3864) aged 11-14 years across Kuwait. Information on eczema symptoms and clinical history, use of antihistamines, parental history of eczema, mode of delivery, and childhood life-style factors and exposures were reported by parents. Current eczema was defined as chronic or chronically relapsing itchy dermatitis with characteristic morphology and distribution in the past 12 months. Among subjects reporting current itchy rash, frequency of nocturnal sleep disturbance due to itchy rash in the past 12 months was reported as: never, <1 night per week, and ≥1 nights per week. Associations were assessed by applying a modified Poisson regression to estimate adjusted prevalence ratios (aPR) and 95% confidence intervals (CI).

Results

The prevalence estimate of current (past 12 months) itchy rash was 20.5% (735/3593) and current eczema was 10.2% (388/3791), with 19.5% (736/3775) reporting history of ever doctor-diagnosed eczema. Among subjects with current itchy rash, nocturnal sleep disturbance due to itchy rash affected 21.7% (157/724) of participants for <1 night per week and affected 12.7% (92/724) of participants for ≥1 nights per week. Antihistamine use at least once per month increased as the frequency of nocturnal sleep disturbance due to itchy rash increased (P_trend <0.001). Factors that demonstrated association with current eczema prevalence included underweight body mass index (aPR = 1.71, 95% CI: 1.16-2.53), Cesarean section delivery (1.29, 1.01-1.65), and maternal (1.72, 1.35-2.19) and paternal (1.83, 1.44-2.32) history of eczema. Frequent (≥1 nights per week) nocturnal sleep disturbance was associated with Cesarean section delivery (1.98, 1.37-2.85), exposure to household tobacco smoke (1.70, 1.18-2.47), and dog-keeping (1.93, 1.06-3.52).

Conclusions

Eczema symptoms are common among adolescents in Kuwait, with similar epidemiological patterns as those observed in western countries. A large proportion of affected adolescents reported nocturnal sleep disturbance due to itchy rash. Modifiable risk factors were associated increased prevalence of eczema and night awakenings.

Sex-specific developmental trajectories of eczema from infancy to age 26 years: A birth cohort study

BACKGROUND

Eczema is a common inflammatory skin disease with varying developmental trajectories/patterns that are influenced by different risk factors. The aim of this study was to investigate eczema development from infancy to early adulthood by identifying distinct developmental trajectories that describe disease patterns over time and evaluate the role of prenatal and early-life risk factors.

METHODS

The Isle of Wight Birth Cohort (n = 1456) was prospectively assessed at birth, 1, 2, 4, 10, 18 and 26 years. In all assessments, eczema was defined as chronic or chronically relapsing itchy dermatitis lasting >6 weeks with characteristic morphology and distribution in the past 12 months. Developmental trajectories of eczema between 1 or 2 and 26 years were identified separately for males and females by applying semiparametric mixture models. Associations were assessed by applying a modified Poisson regression to estimate adjusted risk ratios (aRR) and 95% confidence intervals (CI).

RESULTS

In both males and females, the following eczema developmental trajectories were identified: unaffected/transient (males: 77.7% vs. females: 73.0%), mid-onset late-resolving (males: 7.8% vs. females: 4.4%), late-onset (males: 5.2% vs. females: 9.5%) and early-onset persistent (males: 9.3% vs. females: 5.4%). In females, an additional trajectory was identified as follows: early-onset early-resolving (7.7%). Among males, filaggrin gene (FLG) variants (aRR = 2.45, 95% CI: 1.34-4.46) and paternal eczema (2.66, 1.39-5.08) were associated with the early-onset persistent trajectory. Among females, maternal eczema (2.84, 1.42-5.70) and high birthweight (2.25, 1.08-4.69) were associated with the early-onset persistent trajectory.

CONCLUSIONS

Four and five trajectories represented eczema development among males and females, respectively, with different predisposing risk factors. Our results indicate that males and females may experience a different course of eczema.

Atopic Dermatitis: Conventional and Integrative Medicine

Although Western medicine and ideas about atopic dermatitis (AD) have become popular in many Asian countries, local beliefs about the disease and its treatment often prevail. The multi- racial background of these countries as well as the influence of the diverse religions (such as Taoism and Ramadan) in these regions often lead to diverse belief systems about the causes of AD (such as the Chi concept, also known as the balance of yin and yang) and the types of treatment (e.g. herbal remedies, topical versus concoctions, and decoctions). In addition, many of the cultural practices are preserved among the Southeast Asian minorities residing in the United Kingdom and North America. Eastern treatments typically take a holistic approach to AD and emphasize the psychosomatic component of the disorder. This overview provides a summary of the difference between conventional, complementary, alternative, and integrative medicine in terms of epidemiology, aetiology, therapy, and prognosis in children with AD. There are a number of similarities in genetic and environmental factors in epidemiology and aetiology; however, differences exist in terms of the concept of management. Complementary and alternative medicine, traditional Chinese medicine, and integrative medicine usage are not only prevalent among the Asian population but are also becoming more popular and accepted in Western societies.

Oral Administration of Live and Dead Cells of Lactobacillus sakei proBio65 Alleviated Atopic Dermatitis in Children and Adolescents: a Randomized, Double-Blind, and Placebo-Controlled Study

Several studies suggest that probiotics might be useful in the management of atopic dermatitis (AD). However, the efficacy and comparison between both the administration of viable and non-viable probiotics on alleviation of AD is not well studied. Therefore, the purpose of this study was to evaluate the effect of L. sakei proBio65 live and dead cells when administered (1 × 10¹⁰ cells/day) for 12 weeks to children and adolescents (aged 3 to 18) with atopic dermatitis. In this randomized double-blind, placebo-controlled study, ninety patients were recruited and randomly allocated to either the L. sakei proBio65 live cells, L. sakei proBio65 dead cells, or placebo groups. Assessment of efficacy was based on the change in SCORing Atopic Dermatitis (SCORAD) score, Investigators Global Assessment (IGA) score, serum inflammatory markers such as the serum eosinophil (count), IgE, eosinophil cationic protein (ECP), CCL17 (thymus and activation-regulated chemokine [TARC]), and CCL27 (cutaneous T cell-attracting chemokine [CTACK]), and changes in skin condition (moisture and sebum) at baseline, week 6 and week 12. The SCORAD total score decreased in the live cells (p = 0.0015) and dead cell group (p = 0.0017) from the baseline after 12 weeks, whereas there were no significant changes in the placebo group when compared with baseline. The skin sebum content increased in both the live cell (p < 0.0001) and the dead cell group (p < 0.0001), suggesting potential improvements in skin barrier functions. Current data suggested a positive improvement in alleviation of AD symptoms upon oral administration of L. sakei proBio65 in both viable and non-viable forms.

The Role of Genetics, the Environment, and Epigenetics in Atopic Dermatitis

Atopic Dermatitis (AD) is a common inflammatory disease with a genetic background. The prevalence of AD has been increasing in many countries. AD patients often have manifestations of pruritus, generalized skin dryness, and eczematous lesions. The pathogenesis of AD is complicated. The impaired skin barrier and immune imbalance play significant roles in the development of AD. Environmental factors such as allergens and pollutants are associated with the increasing prevalence. Many genetic and environmental factors induce a skin barrier deficiency, and this can lead to immune imbalance, which exacerbates the impaired skin barrier to form a vicious cycle (outside-inside-outside view). Genetic studies find many gene mutations and genetic variants, such as filaggrin mutations, which may directly induce the deficiency of the skin barrier and immune system. Epigenetic studies provide a connection between the relationship of an impaired skin barrier and immune and environmental factors, such as tobacco exposure, pollutants, microbes, and diet and nutrients. AD is a multigene disease, and thus there are many targets for regulation of expression of these genes which may contribute to the pathogenesis of AD. However, the epigenetic regulation of environmental factors in AD pathogenesis still needs to be further researched.

Contributions of innate lymphocytes to allergic responses

PURPOSE OF REVIEW

Allergic diseases represent a growing global health concern, especially among pediatric populations. Current strategies for the treatment of allergies and asthma focus on limiting the severity of the symptoms; however, additional research investigating the mechanisms promoting inflammation in the context of allergic reactions may lead to the development of more effective therapeutic strategies.

RECENT FINDINGS

Novel studies have highlighted the contributions of innate lymphocytes to the induction of inflammatory responses to allergens. Remarkably, neuron-derived signals, hormones, and even vitamins have been suggested to modulate the activity of innate lymphocytes, opening new windows of opportunity for the treatment of allergic inflammation.

SUMMARY

These studies highlight the complex interactions of the nervous, endocrine, and immune system that promote pathology in the context of allergic inflammation. Further studies are required to understand these interactions in order to aid in the development of novel and much-needed therapies to treat allergic conditions.

Nationwide survey of the prevalence of wheeze, rhino-conjunctivitis, and eczema among Japanese children in 2015

BACKGROUND

Global surveys and cohort studies have been conducted to evaluate the prevalence of allergic disease in childhood, but only a few nationwide surveys have been conducted in Japan. We aimed to report the prevalence of childhood allergic disease in Japan and determine the prevalence distribution by sex and prefecture.

METHODS

In 2015, we conducted a school-based questionnaire survey using the Japanese version of the International Study of Asthma and Allergies in Childhood questionnaire among two age groups: primary school students (PS, 6-8 years old) and middle school students (MS, 13-15 years old). The schools were randomly selected from each prefecture.

RESULTS

Valid responses were obtained from 42,582 PS and 36,638 MS. Among PS and MS, the prevalence of wheeze was 10.2% and 8.2%, that of allergic rhino-conjunctivitis was 18.7% and 26.7%, and that of eczema was 14.6% and 9.7%, respectively. In terms of sex, the prevalence of wheeze and rhino-conjunctivitis was higher in male PS while that of rhino-conjunctivitis and eczema was higher in female MS. In terms of prefecture, there was a two-fold difference in the prevalence of wheeze and eczema and a four-fold difference in the prevalence of rhino-conjunctivitis, with each disease showing different distribution patterns.

CONCLUSIONS

We demonstrated the prevalence of allergic disease among PS and MS in 2015. The prevalence tended to be higher in male PS and female MS. Each disease exhibited different prevalence ranges and distributions. Identifying the factors behind these differences is a topic for future research.

Breastfeeding duration modifies the effect of smoking during pregnancy on eczema from early childhood to adolescence

BACKGROUND

Cigarette smoke contains compounds similar to coal tar, an ancient remedy of eczema. Some studies have reported protective effects of maternal gestational smoking on offspring eczema; however, others have shown no or increased risks. Similarly, studies linking breastfeeding duration and eczema have demonstrated contradictory findings. No study has yet investigated combined effects of these two factors on eczema.

OBJECTIVE

Since tobacco compounds can pass to offspring via breast milk, we investigated their combined effects on eczema development from childhood to adolescence.

METHODS

We obtained information regarding gestational smoking, exclusive breastfeeding duration, and eczema at ages 1-or-2, 4, 10, and 18 years from the Isle of Wight (IOW) birth cohort, UK. Using generalized estimating equations, we assessed the interaction of gestational smoking and residual exclusive breastfeeding duration (Resid-BF-duration, obtained by regressing the latter on maternal smoking) on eczema over time adjusting for confounders. For the three transition periods of 1-or-2 to 4 years, 4-10, and 10-18 years, we estimated risks of persistent, incident, and remitting eczema associated with the interaction using repeated measurements.

RESULTS

If the mother smoked during gestation, longer Resid-BF-duration was associated with a lower risk of eczema, compared to if she did not smoke. The risk ratios (95% CI) if the mother smoked during gestation and exclusively breastfed for at least 3, 9, 15, 21 weeks are 0.7 (0.6, 1.7), 0.6 (0. 4, 0.9), 0.5 (0.3, 0.8), and 0.4 (0.2, 0. 8), respectively. Additionally, in all three transition periods, the risk of persistent eczema was lower with longer Resid-BF-duration if the mother smoked during gestation.

CONCLUSIONS AND CLINICAL RELEVANCE

Results suggest a protective effect of gestational smoking combined with longer duration of exclusive breastfeeding on early-onset persistent eczema. Future studies should examine underlying biological mechanisms. Prolonged breastfeeding should be encouraged even if the mother smoked during gestation.

Disease trajectories in childhood atopic dermatitis: an update and practitioner's guide

BACKGROUND

Atopic dermatitis (AD) is a heterogeneous disease with a multifactorial aetiology and complex pathophysiology. This heterogeneity translates into different trajectories of disease progression with respect to severity, persistence and risk of development of atopic comorbidities. Determining which possible disease trajectories or comorbidities any individual child might develop is challenging in clinical practice. Tools that help identify paediatric patients at higher risk of disease progression would greatly aid clinicians.

METHODS

We reviewed recent cohort studies to synthesize and simplify the epidemiological data to try to identify shared clinically relevant characteristics that may help physicians estimate the risk of disease progression in paediatric patients with AD.

RESULTS

Despite the variability in data collection and methods of analysis and their limitations, there are common patterns of early-childhood AD that may aid in the estimation of risk for disease progression. Factors associated with risk of AD progression include younger age of onset, family history of atopy, greater AD severity, filaggrin mutations, urban environment and polysensitization and/or allergic multimorbidity. Based on these factors, we provide a practitioner's guide for identifying, counselling and/or referring infants and children with AD at potentially higher risk of developing persistent AD and atopic comorbidities. We also present clinical scenarios to illustrate how these data relate to real-life situations.

CONCLUSIONS

Useful insights are provided for physicians and patients to inform them better about the risk of AD progression and to help guide care pathways for the paediatric population with AD. What's already known about this topic? The complex pathophysiology of atopic dermatitis (AD) translates into a heterogeneous clinical presentation and trajectories of disease progression. Although the consensus is that most paediatric patients with AD will eventually 'outgrow' the disease or follow the longitudinal trajectory known as the 'atopic march', a significant proportion will develop persistent AD and/or other atopic conditions. No known factors conclusively predict the risk of progression or development of comorbidities. What does this study add? Recent analyses of data from large cohorts of paediatric patients with AD have suggested the existence of potentially discrete clusters of patients who present with relatively common AD phenotypes. These studies have shed some light onto the factors associated with risk of progression, which we review in this article. A practitioner's guide with clinical scenarios is provided to help identify patients at high risk of progression to determine whether a patient should be monitored and/or would require specialist referral.

Different definitions of atopic dermatitis: impact on prevalence estimates and associated risk factors

Background

There is no objective test that can unequivocally confirm the diagnosis of atopic dermatitis (AD), and no uniform clinical definition.

Objectives

To investigate to what extent operational definitions of AD cause fluctuation in the prevalence estimates and the associated risk factors.

Methods

We first reviewed the operational definitions of AD used in the literature. We then tested the impact of the choice of the most common definitions of ‘cases’ and ‘controls’ on AD prevalence estimates and associated risk factors (including filaggrin mutations) among children aged 5 years in two population‐based birth cohorts: the Manchester Asthma and Allergy Study (MAAS) and Asthma in Ashford. Model performance was measured by the percentage of children within an area of clinical indecision (defined as having a posterior probability of AD between 25% and 60%).

Results

We identified 59 different definitions of AD across 45 reviewed studies. Of those, we chose four common ‘case’ definitions and two definitions of ‘controls’. The prevalence estimates using different case definitions ranged between 22% and 33% in MAAS, and between 12% and 22% in Ashford. The area of clinical indecision ranged from 32% to 44% in MAAS and from 9% to 29% in Ashford. Depending on the case definition used, the associations with filaggrin mutations varied, with odds ratios (95% confidence intervals) ranging from 1·8 (1·1–2·9) to 2·2 (1·3–3·7) in MAAS and 1·7 (0·8–3·7) to 2·3 (1·2–4·5) in Ashford. Associations with filaggrin mutations also differed when using the same ‘case’ definition but different definitions of ‘controls’.

Conclusions

Use of different definitions of AD results in substantial differences in prevalence estimates, the performance of prediction models and association with risk factors.

What's already known about this topic?

There is no objective test that can unequivocally confirm the diagnosis of atopic dermatitis (AD) and no uniform clinical definition.

This results in different definitions utilized in AD studies, raising concerns on the generalizability of the results and comparability across different studies.

What does this study add?

This study has shown that different definitions of ‘cases’ and ‘controls’ have major impacts upon prevalence estimates and associations with risk factors, including genetics, in two population‐based birth cohorts.

These findings suggest the importance of developing a consensus on AD definitions of both ‘controls’ and ‘cases’ to minimize biases in studies.

https://www.bjdonline.com/article/different-definitions-of-atopic-dermatitis-impact-on-prevalence-estimates-and-associated-risk-factors/

Linked Comment: https://doi.org/10.1111/bjd.18303.

https://doi.org/10.1111/bjd.18571 available online

The prevalence of atopic dermatitis beyond childhood: A systematic review and meta-analysis of longitudinal studies

BACKGROUND

There are sparse and conflicting data regarding the long-term clinical course of atopic dermatitis (AD). Although often described as a childhood disease, newer population-based estimates suggest the prevalence of pediatric and adult disease may be similar.

METHODS

Our objective was to determine whether there is a decline in the prevalence of AD in population-based cohorts of patients followed longitudinally beyond childhood. We conducted a systematic review and meta-analysis including studies assessing AD prevalence across 3 or more points in time. The primary outcome was weighted overall risk difference (percentage decrease in AD prevalence).

RESULTS

Of 2080 references reviewed, 7 studies with 13 515 participants were included. Participants were assessed at 3-6 time points, ranging from age 3 months to 26 years. The percentage decrease in prevalence after age 12 was 1%, which was not significantly different from zero (95% confidence interval -2%-5%). Similar results were found with other age cut-offs.

CONCLUSION

The prevalence of AD in longitudinal birth cohort studies is similar in childhood and adolescence/early adulthood.

Acquisition, remission, and persistence of eczema, asthma, and rhinitis in children

BACKGROUND

Allergic sensitization is associated with eczema, asthma, and rhinitis. However, it is unknown whether and how allergic sensitization is associated over time with acquisition, remission, and persistence of these diseases and their comorbidity.

OBJECTIVE

To gain a better understanding of factors including allergic sensitization transitions that influence the temporal pattern of asthma, eczema, and rhinitis and their comorbidity during childhood.

METHODS

In the Isle of Wight birth cohort, information on allergic sensitization to common allergens was collected at ages 4, 10, and 18 years along with asthma, rhinitis, and eczema status determined by clinical diagnosis. Logistic regressions were used to estimate subsequent and concurrent odds ratios of diseases transition with allergic sensitization transition status as the main independent variable. Two transition periods were considered, 4 to 10 years of age and 10 to 18 years of age.

RESULTS

The odds of new diagnosis of allergic disease (no-yes) was increased among subjects with acquired or persistent allergic sensitization to common allergens compared to subjects with no sensitization (acquisition of sensitization odds ratio [OR]=3.22, P < .0001; persistence of sensitization, OR=6.33, P < .0001). The odds of remission of allergic diseases (yes-no) was lower among subjects with acquired or sustained allergic sensitization (acquisition, OR=0.18, P = .0001; persistence, OR=0.085, P < .0001), compared to subjects not sensitized. Subjects with acquired or persistent allergic sensitization were also had higher odds for persistence of disease (yes-yes) than subjects not sensitized (acquisition, OR=5.49, P = .0001; persistence, OR=11.79, P < .0001).

CONCLUSION

Transition of allergic sensitizations to common allergens is a prognostic factor for subsequent or concurrent transition of eczema, asthma, and rhinitis. Prevention or reduction in allergic sensitization has a potential to lead to remission of these conditions.

The Prevalence and Risk Factors of Atopic Dermatitis and Clinical Characteristics according to Disease Onset in 19-Year-Old Korean Male Subjects

Background

The natural course of atopic dermatitis (AD) in infancy, childhood, and adolescence is not yet completely known.

Objective

To investigate the prevalence and risk factors of atopic dermatits among 19-year-old Korean male subjects.

Methods

All 19-year-old Korean males must undergo medical examination for conscription. We precisely evaluated the prevalence of AD in three Korean provinces using the information from this physical checkup. AD was diagnosed by experienced dermatologists according to the Hanifin and Rajka criteria. The disease severity was assessed by the scoring of atopic dermatitis (SCORAD) index. In order to investigate the risk factors for AD, a questionnaire was administered to all subjects regarding parental atopic history, geographical characteristics of past habitation, past economic status, number of siblings, parental occupation, etc.

Results

The point prevalence in the Korean provinces ranged from 1.15% to 1.44%. In multivariable analysis, a parental history of AD was a significant risk factor in all 3 disease-onset groups (infancy, childhood, and adolescent onset). In the infancy-onset group, low economic status was also a significant risk factor for AD. The SCORAD index was significantly higher in AD subjects with early onset and those living in small-sized habitations. Moreover, erythema, edema, lichenification, dryness of skin, and sleep loss appeared to be more severe in early-onset cases.

Conclusion

The younger the age of disease onset, the more severe the clinical outcomes in 19-year-old male subjects. In addition, active AD treatment at younger ages might affect the prevalence and the severity of AD in adulthood.

Sex differences in the immune response to experimental stroke: Implications for translational research

Ischemic stroke is a leading cause of death and disability in the United States. It is known that males and females respond differently to stroke. Depending on age, the incidence, prevalence, mortality rate, and disability outcome of stroke differ between the sexes. Females generally have strokes at older ages than males and, therefore, have a worse stroke outcome. There are also major differences in how the sexes respond to stroke at the cellular level. Immune response is a critical factor in determining the progress of neurodegeneration after stroke and is fundamentally different for males and females. Additionally, females respond to stroke therapies differently from males, yet they are often left out of the basic research that is focused on developing those therapies. With a resounding failure to translate stroke therapies from the bench to the bedside, it is clearer than ever that inclusion of both sexes in stroke studies is essential for future clinical success. This Mini-Review examines sex differences in the immune response to experimental stroke and its implications for therapy development. © 2016 Wiley Periodicals, Inc.

Sex Differences in Asthma: A Key Role of Androgen-Signaling in Group 2 Innate Lymphoid Cells

Infectious diseases, autoimmune diseases, and also allergy differentially affect women and men. In general, women develop strongest immune responses and thus the proportion of infected individuals and the severity of many viral, bacterial, or parasitic infections are increased in men. However, heightened immunity in women makes them more susceptible than men to autoimmunity and allergy. While sex differences in immunity are well documented, little is known about the cellular and molecular mechanisms underlying these immunological differences, particularly in allergic asthma. Asthma is a chronic inflammation of the airways mediated by exacerbated type 2 immune responses. Sex differences have been reported in the incidence, prevalence, and severity of asthma. While during childhood, males are more susceptible to asthma than females, there is a switch at the onset of puberty as for many other allergic diseases. This decrease of asthma incidence around puberty in males suggests that hormonal mediators could play a protective role in the susceptibility to allergic responses in male. Group 2 innate lymphoid cells (ILC2s) have recently emerged as critical players in the initiation of allergic responses, but also in the resolution of parasitic infection, through their capacity to rapidly and potently produce type 2 cytokines. This review will cover the current understanding of the impact of sex-linked factors in allergic inflammation, with a particular focus on the role of sex hormones on the development and function of tissue-resident ILC2s.

Prevalence and Risk Factors of Asthma, Rhinitis, and Eczema and Their Multimorbidity among Young Adults in Kuwait: A Cross-Sectional Study

OBJECTIVE

To estimate the prevalence of allergic diseases and allergic multimorbidity (coexistence) among young adults in Kuwait and to examine associations between risk factors with allergic diseases and allergic multimorbidity.

METHODS

A cross-sectional study was conducted by enrolling 1,154 students, aged 18-26 years, attending Kuwait University. Participants self-completed a questionnaire on symptoms and clinical history of allergic diseases. Prevalence ratios (PRs) and 95% confidence intervals (CIs) were estimated by applying Poisson regression with robust variance estimation.

RESULTS

The prevalence of current asthma, rhinitis, and eczema was estimated to be 11.9% (135/1135), 20.4% (232/1138), and 9.2% (105/1143), respectively. The coexistence of "asthma and rhinitis" (5.1%, 57/1125) was the most frequent allergic multimorbidity. Both maternal history (PR = 3.97, 95% CI: 2.32-6.80) and paternal history (PR = 1.72, 95% CI: 1.10-2.68) of allergy were independently associated with having two or more coexisting allergic diseases. The joint effect of having both maternal and paternal history of allergy was associated with 8.16 times (95% CI: 4.19-15.90) higher risk of allergic multimorbidity.

CONCLUSION

Allergic diseases and allergic multimorbidity are common among young adults in Kuwait and their burden mirrors that of westernized countries. Parental history of allergy is a strong predisposing factor for allergic multimorbidity.

The Long-Term Course of Atopic Dermatitis

Atopic dermatitis (AD) is a chronic, relapsing condition, meaning that the intensity of symptoms usually fluctuates over time. Changes in skin physiology may be evident from birth, suggesting that AD may be a lifelong condition marked by intermittent symptoms/disease activity. Methodological considerations for studying the long-term course of AD are reviewed in detail. Improved measurement of the frequency and duration of active disease periods can help to elucidate more about the clinical course AD and the role of treatment in long-term outcomes.

Persistence of atopic dermatitis (AD): A systematic review and meta-analysis

BACKGROUND

Previous studies found conflicting results about whether childhood atopic dermatitis (AD) persists into adulthood.

OBJECTIVE

We sought to determine persistence rates and clinical factors associated with prolonged AD.

METHODS

A systematic review was performed in MEDLINE, EMBASE, Scopus, GREAT, LILACS, Web of Science, Academic Search Complete, and Cochrane Library. Meta-analysis was performed using Kaplan-Meier plots and random-effects proportional hazards regression.

RESULTS

In total, 45 studies including 110,651 subjects spanning 434,992 patient-years from 15 countries were included. In pooled analysis, 80% of childhood AD did not persist by 8 years and less than 5% persisted by 20 years after diagnosis (mean ± SE: 6.1 ± 0.02 years). Children with AD that persisted already for more than 10 years (8.3 ± 0.08 years) had longer persistence than those with 3 (3.2 ± 0.02 years) or 5 (6.8 ± 0.06 years) years of persistence. Children who developed AD by age 2 years had less persistent disease (P < .0001). Persistence was greater in studies using patient-/caregiver-assessed versus physician-assessed outcomes, female versus male patients (P ≤ .0006), but not in those with sensitivity to allergens (P = .90). Three studies found prolonged persistence with more severe AD.

LIMITATIONS

Some studies did not capture recurrences later in life.

CONCLUSIONS

Most childhood AD remitted by adulthood. However, children with already persistent disease, later onset, and/or more severe disease have increased persistence.

Different risk factor patterns for adult asthma, rhinitis and eczema: results from West Sweden Asthma Study

BACKGROUND

Atopic diseases including asthma, rhinitis and eczema have increased in the second half of the past century. This has been well studied among children and adolescents but with the exception of asthma to a much lesser extent in adults. The adult risk factor pattern of atopic diseases, in particular of eczema, and their relation to allergic sensitization are yet to be fully elucidated. Studies among adults that have compared the risk factor pattern for these conditions in the same material are very few. The objective of this study was to compare the risk factor patterns for asthma, rhinitis and eczema in a randomly selected adult population.

METHODS

A questionnaire survey on atopic diseases was dispatched by mail to 30,000 randomly selected individuals in West Sweden aged 16-75 years and 62 % participated. A subgroup of 2000 individuals was selected for clinical examinations including blood sampling for specific serum Immunoglobulin E to common airborne allergens and 1172 attended.

RESULTS

The prevalence of current asthma was 11.8 %, current rhinitis 42.8 %, current eczema 13.5 and 2.3 % had all three conditions while 13.9 % had at least two conditions. No mutual risk factor was identified for all three conditions. Allergic sensitization was a strong risk factor for current asthma (OR 4.1 CI 2.7-6.3) and current rhinitis (OR 5.1 CI 3.8-6.9) but not so for current eczema. Obesity was a risk factor for current asthma and current rhinitis, while farm childhood decreased the risk for current asthma and current rhinitis. Occupational exposure to gas dust or fumes and female sex was associated with an increased risk of current asthma and current eczema.

CONCLUSIONS

There are different risk factor patterns for asthma, rhinitis and eczema in adults but some risk factors are overlapping between some of the conditions. The effect of mutable risk factors should be assessed further in longitudinal studies.

Are allergic multimorbidities and IgE polysensitization associated with the persistence or re-occurrence of foetal type 2 signalling? The MeDALL hypothesis

Allergic diseases [asthma, rhinitis and atopic dermatitis (AD)] are complex. They are associated with allergen-specific IgE and nonallergic mechanisms that may coexist in the same patient. In addition, these diseases tend to cluster and patients present concomitant or consecutive diseases (multimorbidity). IgE sensitization should be considered as a quantitative trait. Important clinical and immunological differences exist between mono- and polysensitized subjects. Multimorbidities of allergic diseases share common causal mechanisms that are only partly IgE-mediated. Persistence of allergic diseases over time is associated with multimorbidity and/or IgE polysensitization. The importance of the family history of allergy may decrease with age. This review puts forward the hypothesis that allergic multimorbidities and IgE polysensitization are associated and related to the persistence or re-occurrence of foetal type 2 signalling. Asthma, rhinitis and AD are manifestations of a common systemic immune imbalance (mesodermal origin) with specific patterns of remodelling (ectodermal or endodermal origin). This study proposes a new classification of IgE-mediated allergic diseases that allows the definition of novel phenotypes to (i) better understand genetic and epigenetic mechanisms, (ii) better stratify allergic preschool children for prognosis and (iii) propose novel strategies of treatment and prevention.

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.

Allergic multimorbidity of asthma, rhinitis and eczema over 20 years in the German birth cohort MAS

BACKGROUND

The occurrence of allergic multimorbidity (coexistence of asthma, allergic rhinitis and eczema) has not been evaluated longitudinally from early childhood up to adulthood in a population-based study sample. We aimed to determine the prevalence of allergic multimorbidity up to age 20 stratified by parental allergies and sex/gender using extensive prospective follow-up data from two decades of a birth cohort study.

METHODS

In 1990, we recruited 1314 healthy newborns from 6 maternity wards across Germany for the population-based MAS birth cohort study. The sample was purposely risk-enriched by increasing the proportion of children at high allergy risk (i.e. at least 2 allergic family members among parents and siblings) from 19% in the source population to 38% in the final sample. The remaining 62% of all MAS children had a low or no allergy risk. Symptoms, medication and doctor's diagnoses of allergic diseases have been assessed using standardized questionnaires including validated ISAAC questions in 19 follow-up assessments up to age 20. Allergic multimorbidity at each time point was defined as the coexistence of at least 2 of the following diseases in one participant: asthma, allergic rhinitis and eczema.

RESULTS

Response at age 20 was 72% (n = 942) of all recruited participants. At age 20, 18.5% (95% CI, 15.0-22.5%) of all participants with allergic parents had 2 or 3 concurrent allergies as compared to only 6.3% (95% CI, 4.3-9.0%) of those with non-allergic parents. At this age, allergic multimorbidity was similar in women and men (12.7% (95% CI, 9.7-16.2%) vs. 11.6% (95% CI, 8.9-14.8%)), whereas single allergic diseases were slightly more common in women than men (24.2% (95% CI, 20.2-28.5%) vs. 20.1% (95% CI, 16.6-24.0%)). Asthma occurred more frequently with coexisting allergic rhinitis and/or eczema than as a single entity from pre-puberty to adulthood.

CONCLUSION

Having parents with allergies is not only a strong predictor to develop any allergy, but it strongly increases the risk of developing allergic multimorbidity. In males and females alike, coexisting allergies were increasingly common throughout adolescence up to adulthood. Particularly asthma occurred in both sexes more frequently with coexisting allergies than as a single entity.

Identifying CpG sites associated with eczema via random forest screening of epigenome-scale DNA methylation

BACKGROUND

The prevalence of eczema is increasing in industrialized nations. Limited evidence has shown the association of DNA methylation (DNA-M) with eczema. We explored this association at the epigenome-scale to better understand the role of DNA-M. Data from the first generation (F1) of the Isle of Wight (IoW) birth cohort participants and the second generation (F2) were examined in our study. Epigenome-scale DNA methylation of F1 at age 18 years and F2 in cord blood was measured using the Illumina Infinium HumanMethylation450 Beadchip. A total of 307,357 cytosine-phosphate-guanine sites (CpGs) in the F1 generation were screened via recursive random forest (RF) for their potential association with eczema at age 18. Functional enrichment and pathway analysis of resulting genes were carried out using DAVID gene functional classification tool. Log-linear models were performed in F1 to corroborate the identified CpGs. Findings in F1 were further replicated in F2.

RESULTS

The recursive RF yielded 140 CpGs, 88 of which showed statistically significant associations with eczema at age 18, corroborated by log-linear models after controlling for false discovery rate (FDR) of 0.05. These CpGs were enriched among many biological pathways, including pathways related to creating transcriptional variety and pathways mechanistically linked to eczema such as cadherins, cell adhesion, gap junctions, tight junctions, melanogenesis, and apoptosis. In the F2 generation, about half of the 83 CpGs identified in F1 showed the same direction of association with eczema risk as in F1, of which two CpGs were significantly associated with eczema risk, cg04850479 of the PROZ gene (risk ratio (RR) = 15.1 in F1, 95 % confidence interval (CI) 1.71, 79.5; RR = 6.82 in F2, 95 % CI 1.52, 30.62) and cg01427769 of the NEU1 gene (RR = 0.13 in F1, 95 % CI 0.03, 0.46; RR = 0.09 in F2, 95 % CI 0.03, 0.36).

CONCLUSIONS

Via epigenome-scaled analyses using recursive RF followed by log-linear models, we identified 88 CpGs associated with eczema in F1, of which 41 were replicated in F2. Several identified CpGs are located within genes in biological pathways relating to skin barrier integrity, which is central to the pathogenesis of eczema. Novel genes associated with eczema risk were identified (e.g., the PROZ and NEU1 genes).

Allergic sensitization and filaggrin variants predispose to the comorbidity of eczema, asthma, and rhinitis: results from the Isle of Wight birth cohort

BACKGROUND

Allergic sensitization and filaggrin gene (FLG) variants are important risk factors for allergic disorders; however, knowledge on their individual and interactive effects on the coexistence of eczema, asthma, and rhinitis is lacking.

OBJECTIVE

This study aimed at investigating the single and combined effects of allergic sensitization and FLG variants on the development of single and multiple allergic disorders.

METHODS

The Isle of Wight birth cohort (n = 1456) has been examined at 1, 2, 4, 10, and 18 years of age. Repeated measurements of eczema, asthma, rhinitis, and skin prick tests were available for all follow-ups. FLG variants were genotyped in 1150 participants. Associations of allergic sensitization and FLG variants with single and multiple allergic disorders were tested in log-binomial regression analysis.

RESULTS

The prevalence of eczema-, asthma-, and rhinitis-only ranged from 5.6% to 8.5%, 4.9% to 10.2%, and 2.5% to 20.4%, respectively, during the first 18 years of life. The coexistence of allergic disorders is common, with approximately 2% of the population reporting the comorbidity of 'eczema, asthma, and rhinitis' during the study period. In repeated measurement analyses, allergic sensitization and FLG variants, when analysed separately, were associated with having single and multiple allergic disorders. Of particular significance, their combined effect increased the risk of 'eczema and asthma' (RR = 13.67, 95% CI: 7.35-25.42), 'asthma and rhinitis' (RR = 7.46, 95% CI: 5.07-10.98), and 'eczema, asthma, and rhinitis' (RR = 23.44, 95% CI: 12.27-44.78).

CONCLUSIONS AND CLINICAL RELEVANCE

The coexistence of allergic disorders is frequent, and allergic sensitization and FLG variants jointly increased risk of allergic comorbidities, which may represent more severe and complex clinical phenotypes. The interactive effect and the elevated proportion of allergic comorbidities associated with allergic sensitization and FLG variants emphasize their joint importance in the pathogenesis of allergic disorders.

Allergy-related diseases and recurrent abdominal pain during childhood - a birth cohort study

BACKGROUND

Allergy and immune dysregulation may have a role in the pathophysiology of recurrent abdominal pain of functional origin, but previous studies of allergy-related diseases and abdominal pain have contradictory results.

AIM

To examine the association between allergy-related diseases or sensitisation during childhood and abdominal pain at age 12 years.

METHODS

In this birth cohort study of 4089 children, parents answered questionnaires regarding asthma, allergic rhinitis, eczema and food hypersensitivity ('allergy-related diseases') at ages 0,1,2,4,8 and 12 years. Blood for analyses of allergen-specific IgE was sampled at 4 and 8 years. At 12 years, the children answered questions regarding abdominal pain. Children with coeliac disease or inflammatory bowel disease were excluded. Associations were examined using multivariable logistic regression.

RESULTS

Among 2610 children with complete follow-up, 9% (n = 237) reported abdominal pain at 12 years. All allergy-related diseases were associated with concurrent abdominal pain at 12 years and the risk increased with increasing number of allergy-related diseases (P for trend <0.001). Asthma at 1 and 2 years and food hypersensitivity at 8 years were significantly associated with abdominal pain at 12 years. There was an increased risk of abdominal pain at 12 years in children sensitised to food allergens at 4 or 8 years, but in stratified analyses, this was confined to children whose parents had not reported food hypersensitivity at time of sensitisation.

CONCLUSION

Allergy-related diseases as well as sensitisation to food allergens were associated with an elevated risk of abdominal pain, and the risk increased with the number of allergy-related diseases.

Epigenomics and allergic disease

Allergic disease development is affected by both genes and the environment, and epigenetic mechanisms are hypothesized to mediate these environmental effects. In this article, we discuss the link between the environment, DNA methylation and allergic disease, as well as questions of causality inherent to analyses of DNA methylation. From the practical side, we describe characteristics of allergic phenotypes and contrast different epidemiologic study designs used in epigenetic research. We examine methodological considerations, how best to conduct preprocessing and analysis of DNA methylation data sets, and the latest methods, technologies and discoveries in this rapidly advancing field. DNA methylation and other epigenetic marks are firmly entwined with allergic disease, a link that may hold the basis for future allergic disease diagnosis and treatment.

Association of filaggrin variants with asthma and rhinitis: is eczema or allergic sensitization status an effect modifier?

BACKGROUND

Associations of variants of the filaggrin gene, i.e. FLG with asthma and rhinitis have been shown to be modulated by eczema status. However, it is unknown whether allergic sensitization status modifies this association. The aim of this study was to determine whether FLG variants need eczema and/or allergic sensitization as a necessary component to execute adverse effects on coexisting and subsequent asthma and rhinitis.

METHODS

In the Isle of Wight birth cohort, repeated measurements of asthma, rhinitis, eczema and allergic sensitization (documented by skin-prick tests) were taken in 1,456 children at the ages of 1, 2, 4, 10 and 18 years. Filaggrin haploinsufficiency was defined as having at least the minor allele of R501X, 2282del4 or S3247X variants. log-binomial regression models were used to test associations and statistical interactions.

RESULTS

FLG variants increased the risk of asthma [risk ratio (RR) 1.39, 95% confidence interval (CI) 1.06-1.80] and rhinitis (RR 1.37, 95% CI 1.16-1.63). In the delayed-effects models, 'FLG variants plus allergic sensitization' and 'FLG variants plus eczema' increased the risk of subsequent asthma by 4.93-fold (95% CI 3.61-6.71) and 3.33-fold (95% CI 2.45-4.51), respectively, during the first 18 years of life. In contrast, neither eczema nor allergic sensitization in combination with FLG variants increased the risk of later rhinitis.

CONCLUSIONS

Allergic sensitization and eczema modulated the association between FLG variants and asthma but not rhinitis. Our results imply that the mechanisms and pathways through which FLG variants predispose to an increased risk of asthma and rhinitis may be different.

Persistence of mild to moderate atopic dermatitis

IMPORTANCE

Atopic dermatitis (AD) is a common illness of childhood.

OBJECTIVE

To evaluate the natural history of AD and determine the persistence of symptoms over time.

DESIGN, SETTING, AND PARTICIPANTS

A cross-sectional and cohort study of a nation-wide long-term registry of children with AD enrolled in the Pediatric Eczema Elective Registry (PEER).

MAIN OUTCOMES AND MEASURES

Self-reported outcome of whether a child's skin was AD symptom-free for 6 months at 6-month intervals.

RESULTS

A total of 7157 patients were enrolled in the PEER study for a total of 22,550 person-years. At least 2 years of follow-up were observed for 4248 children and at least 5 years of follow-up were observed for 2416 children. Multiple demographic and exposure variables were associated with more persistent AD. At every age (ie, 2-26 years), more than 80% of PEER participants had symptoms of AD and/or were using medication to treat their AD. It was not until age 20 years that 50% of patients had at least 1 lifetime 6-month symptom- and treatment-free period.

CONCLUSIONS AND RELEVANCE

Based on this large longitudinal cohort study, symptoms associated with AD seem to persist well into the second decade of a child's life and likely longer. Atopic dermatitis is probably a life-long illness.

Lung function trajectories from birth through puberty reflect asthma phenotypes with allergic comorbidity

BACKGROUND

Childhood asthma phenotypes reflecting underlying developmental mechanisms are sought, with little information on asthma phenotypes based on allergic comorbidities.

OBJECTIVE

We asked whether lung function trajectories from birth to 16 years were associated with asthma phenotypes with comorbid allergic rhinitis and atopic dermatitis.

METHODS

Lung function (given as z scores) was measured at birth in 329 subjects in the "Environment and Childhood Asthma" birth cohort study in Oslo by using tidal flow volume loops, and at 10 and 16 years by using spirometry. Asthma phenotypes were classified on the basis of recurrent bronchial obstruction at 0 to 2 years, and asthma from the 2- to 10-year and 10- to 16-year intervals, and by combining asthma, atopic dermatitis, and/or allergic rhinitis from 10 to 16 years, stratifying for allergic sensitization. The reference group included 231 subjects without recurrent bronchial obstruction or asthma.

RESULTS

Lung function trajectories differed significantly for asthma comorbidity phenotypes for FEV1, forced expiratory flow at 25% to 75% of forced vital capacity, and FEV1/forced vital capacity (all P < .0001). Significant lung function impairment was observed from birth through 16 years among subjects with asthma, atopic dermatitis, and allergic rhinitis. Lung function trajectories in subjects with asthma at 10 to 16 years or asthma in remission differed significantly for all 3 spirometric values compared with the trajectories in those who never had asthma (P < .0001), but not between asthma groups. Allergic sensitization was not significantly associated with asthma phenotype lung function trajectories.

CONCLUSIONS

The trajectory consisting of impaired lung function from birth throughout childhood in children with asthma, atopic dermatitis, and allergic rhinitis appears less likely to be driven by allergic sensitization, and may imply disease onset in utero, with clinical presentation later in childhood.

Asthma with allergic comorbidities in adolescence is associated with bronchial responsiveness and airways inflammation

BACKGROUND

Childhood asthma frequently has allergic comorbidities. However, there is limited knowledge of the longitudinal development of asthma comorbidites and their association to bronchial hyper-responsiveness (BHR) and airway inflammation markers. We therefore aimed to assess the association between childhood asthma with allergic comorbidities and BHR and fractional exhaled nitric oxide (FE(NO)) and the impact of gender on these associations.

METHODS

Based on data from 550 adolescents in the prospective birth cohort 'Environment and Childhood Asthma' study, asthma was defined for the three time periods 0-2, 2-10 and 10-16 years of age, using recurrent bronchial obstruction (rBO) 0-2 years of age as a proxy for early asthma. Asthma comorbidities included atopic dermatitis (AD) and allergic rhinitis (AR) from 10 to 16 years. At age 16 years BHR, assessed by metacholine bronchial challenge, and airway inflammation, assessed by FE(NO), were compared between the groups of asthma with or without the two comorbidities, to a reference group with no never asthma, and subsequently stratified by gender.

RESULTS

Boys with asthma and AR, regardless of AD had significantly more severe BHR and higher FE(NO) than the other asthma phenotypes. Almost half of the children remained in the asthma and AR category from 10 to 16 years, the entire difference being determined by new incident cases from 10 to 16 years.

CONCLUSIONS

Asthma phenotypes characterized by allergic comorbidities and AR in particular appears closely associated with BHR and FE(NO), especially among boys.

The natural course of sensitization and allergic diseases from childhood to adulthood

BACKGROUND

Longitudinal prospective population-based birth cohort studies of the natural history of sensitization and allergic diseases from childhood to adulthood are few. The aim of the present prospective study was to investigate the natural course of sensitization and allergic diseases in a random population-based sample of 276 children from a 1-year birth cohort of unselected Danish children followed from birth to 26 years of age.

METHODS

Questionnaire-based interviews, physical examination, skin prick tests, specific IgE testing, and from 10 years also spirometry, were carried out at 1.5, 5, 10, 15 and 26 years of age. Predefined diagnostic criteria were used.

RESULTS

Follow-up rates were high, 193 (70%) attended the 26-year follow-up. The prevalence of current eczema was stable during childhood; 13% (1.5 yrs.), 9.2% (5 yrs.), 10.8% (10 yrs.), and 9.8% (15 yrs.), and 5.7% at 26 yrs. From birth to 26 years the cumulative prevalence of eczema, food allergy, asthma, and rhinoconjunctivitis was 23.5%, 13.8%, 17%, and 27.9% respectively. More than half of the participants had one or more allergic disease in the period between birth and 26 years of age. The rates of sensitization (S-IgE = 0.35 kU/l) were 8%, 23%, 26%, 32%, and 31% at 1.5, 5, 10, 15, and 26 years of age, respectively. Sensitization to food allergens was most prevalent in early infancy, whereas sensitization to inhalant allergens dominated later on.

CONCLUSION

The results support the concept of the allergic march. Allergic diseases are not only occurring in childhood but persist into adulthood.

Interactive effect of STAT6 and IL13 gene polymorphisms on eczema status: results from a longitudinal and a cross-sectional study

BACKGROUND

Eczema is a prevalent skin disease that is mainly characterized by systemic deviation of immune response and defective epidermal barrier. Th2 cytokines, such as IL-13 and transcription factor STAT6 are key elements in the inflammatory response that characterize allergic disorders, including eczema. Previous genetic association studies showed inconsistent results for the association of single nucleotide polymorphisms (SNPs) with eczema. Our aim was to investigate whether SNPs in IL13 and STAT6 genes, which share a biological pathway, have an interactive effect on eczema risk.

METHODS

Data from two independent population-based studies were analyzed, namely the Isle of Wight birth cohort study (IOW; n = 1,456) and for the purpose of replication the Swansea PAPA (Poblogaeth Asthma Prifysgol Abertawe; n = 1,445) cross-sectional study. Log-binomial regressions were applied to (i) account for the interaction between IL13 (rs20541) and STAT6 (rs1059513) polymorphisms and (ii) estimate the combined effect, in terms of risk ratios (RRs), of both risk factors on the risk of eczema.

RESULTS

Under a dominant genetic model, the interaction term [IL13 (rs20541) × STAT6 (rs1059513)] was statistically significant in both studies (IOW: adjusted P(interaction) = 0.046; PAPA: P(interaction) = 0.037). The assessment of the combined effect associated with having risk genotypes in both SNPs yielded a 1.52-fold increased risk of eczema in the IOW study (95% confidence interval (CI): 1.05 - 2.20; P = 0.028) and a 2.01-fold higher risk of eczema (95% CI: 1.29 - 3.12; P = 0.002) in the PAPA study population.

CONCLUSIONS

Our study adds to the current knowledge of genetic susceptibility by demonstrating for the first time an interactive effect between SNPs in IL13 (rs20541) and STAT6 (rs1059513) on the occurrence of eczema in two independent samples. Findings of this report further support the emerging evidence that points toward the existence of genetic effects that occur via complex networks involving gene-gene interactions (epistasis).

Pooling birth cohorts in allergy and asthma: European Union-funded initiatives - a MeDALL, CHICOS, ENRIECO, and GA²LEN joint paper

Long-term birth cohort studies are essential to understanding the life course and childhood predictors of allergy and the complex interplay between genes and the environment (including lifestyle and socioeconomic determinants). Over 100 cohorts focusing on asthma and allergy have been initiated in the world over the past 30 years. Since 2004, several research initiatives funded under the EU Framework Program for Research and Technological Development FP6-FP7 have attempted to identify, compare, and evaluate pooling data from existing European birth cohorts (GA(2)LEN: Global Allergy and European Network, FP6; ENRIECO: Environmental Health Risks in European Birth Cohorts, FP7; CHICOS: Developing a Child Cohort Research Strategy for Europe, FP7; MeDALL: Mechanisms of the Development of ALLergy, FP7). However, there is a general lack of knowledge about these initiatives and their potentials. The aim of this paper is to review current and past EU-funded projects in order to make a summary of their goals and achievements and to suggest future research needs of these European birth cohort networks.

Sex and atopy influences on the natural history of rhinitis

PURPOSE OF REVIEW

Rhinitis is a common condition associated with significant under-recognized morbidity and impaired quality of life. The natural history of rhinitis is poorly characterized. Better understanding of its natural history and associated risk factors would improve the ability to effectively manage rhinitis in clinical practice. This review focuses on the current research findings on the natural history of rhinitis and how that is influenced by atopy and sex.

RECENT FINDINGS

Recent work from the Isle of Wight Birth Cohort Study has demonstrated that the prevalence of atopic rhinitis increases steadily in the first 18 years of life in both sexes. However, nonatopic rhinitis behaves differently during adolescence. Its prevalence decreases in boys but continues to increase in girls resulting in a female predominance after puberty. Numerous recent studies have proposed potential roles for sex-related and adipose-related hormonal changes in influencing the course of allergic disease. Further research is needed to establish mechanisms that could underlie such findings.

SUMMARY

Rhinitis becomes increasingly common through childhood, with prevalence during adolescence being mediated by differential effects of sex and atopy. Mechanisms to explain these findings await elucidation.

Immune cells have sex and so should journal articles

Males and females have the same immunological cells, proteins, and pathways in place to protect against the development of disease. The kinetics, magnitude, and skewing of the responses mounted against pathogens, allergens, toxins, or self-antigens, however, can differ dramatically between the sexes. Generally, females mount higher innate and adaptive immune responses than males, which can result in faster clearance of pathogens but also contributes to increased susceptibility to inflammatory and autoimmune diseases in females compared with males. Hormonal and genetic factors contribute significantly to sex differences in immune function and disease pathogenesis. In particular, the expression of X-linked genes and microRNA as well as sex steroid hormones signaling through hormone receptors in immune cells can affect responses to immunological stimuli differently in males and females. Despite data illustrating profound differences between the sexes in immune function, sex differences in the pathogenesis of disease are often overlooked in biomedical research. Establishing journal policies that require authors to report the sex of their cells, animals, and subjects will improve our understanding of the pathogenesis of diseases, with the long-term goal of personalizing treatments for immune-mediated diseases differently for males and females in an effort to protect us equally.

Development and comorbidity of eczema, asthma and rhinitis to age 12: data from the BAMSE birth cohort

BACKGROUND

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.

METHODS

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.

RESULTS

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.

CONCLUSIONS

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.

Interplay of filaggrin loss-of-function variants, allergic sensitization, and eczema in a longitudinal study covering infancy to 18 years of age

Background

Immune specific genes as well as genes regulating the formation of skin barrier are major determinants for eczema manifestation. There is a debate as to whether allergic sensitization and filaggrin gene (FLG) variants lead to eczema or FLG variants and eczema increase the risk of allergic sensitization. To investigate the time-order between eczema and allergic sensitization with respect to FLG variants, data from a large prospective study covering infancy to late adolescence were analyzed.

Methodology/Principal Findings

Repeated measurements of eczema and allergic sensitization (documented by skin prick tests) at ages 1, 2, 4, 10, and 18 years were ascertained in the Isle of Wight birth cohort (n = 1,456). Three transition periods were analyzed: age 1-or-2 to 4, 4 to 10, and 10 to 18 years. FLG variants were genotyped in 1,150 participants. Over the three transition periods, in temporal sequence analyses of initially eczema-free participants, the combined effect of FLG variants and allergic sensitization showed a 2.92-fold (95% CI: 1.47–5.77) increased risk ratio (RR) of eczema in subsequent examinations. This overall risk was more pronounced at a younger age (transition period 1-or-2 to 4, RR = 6.47, 95% CI: 1.96–21.33). In contrast, FLG variants in combination with eczema showed a weaker, but significant, risk ratio for subsequent allergic sensitization only up to 10 years of age.

Conclusions/Significance

Taking the time order into account, this prospective study demonstrates for the first time, that a combination of FLG variants and allergic sensitization increased the risk of eczema in subsequent years. Also FLG variants interacted with eczema and increased the risk of subsequent allergic sensitization, which, was limited to the younger age. Hence, early restoration of defective skin barrier could prevent allergic sensitization and subsequently reduce the risk of eczema development.

Understanding the complexity of IgE-related phenotypes from childhood to young adulthood: a Mechanisms of the Development of Allergy (MeDALL) seminar

Mechanisms of the Development of Allergy (MeDALL), a Seventh Framework Program European Union project, aims to generate novel knowledge on the mechanisms of initiation of allergy. Precise phenotypes of IgE-mediated allergic diseases will be defined in MeDALL. As part of MeDALL, a scientific seminar was held on January 24, 2011, to review current knowledge on the IgE-related phenotypes and to explore how a multidisciplinary effort could result in a new integrative translational approach. This article provides a summary of the meeting. It develops challenges in IgE-related phenotypes and new clinical and epidemiologic approaches to the investigation of allergic phenotypes, including cluster analysis, scale-free models, candidate biomarkers, and IgE microarrays; the particular case of severe asthma was reviewed. Then novel approaches to the IgE-associated phenotypes are reviewed from the individual mechanisms to the systems, including epigenetics, human in vitro immunology, systems biology, and animal models. The last chapter deals with the understanding of the population-based IgE-associated phenotypes in children and adolescents, including age effect in terms of maturation, observed effects of early-life exposures and shift of focus from early life to pregnancy, gene-environment interactions, cohort effects, and time trends in patients with allergic diseases. This review helps to define phenotypes of allergic diseases in MeDALL.

Atopic dermatitis in adolescence

Atopic dermatitis (AD) is a chronic inflammatory skin disorder that typically occurs during childhood especially in the first year of life, with a variable frequency from 10% to 30%. Recent studies have shown that in Europe among 10-20% of children with AD suffer from this disorder also in adolescence. AD is a chronic inflammatory skin disease with a typical onset in the first years of life and with a 10-30% prevalence among young children. AD prevalence in adolescence has been estimated around 5-15% in European countries. AD persists from childhood through adolescence in around 40% of cases and some risk factors have been identified: female sex, sensitization to inhalant and food allergens, allergic asthma and/or rhinoconjunctivitis, the practice of certain jobs. During adolescence, AD mainly appears on the face and neck, often associated with overinfection by Malassezia, and on the palms and soles. AD persistence during adolescence is correlated with psychological diseases such as anxiety; moreover, adolescents affected by AD might have problems in the relationship with their peers. Stress and the psychological problems represent a serious burden for adolescents with AD and cause a significant worsening of the patients' quality of life (QoL). The pharmacological treatment is similar to other age groups. Educational and psychological approaches should be considered in the most severe cases.