Prevalence of allergy-related symptoms in Singaporean children in the second year of life

Delayed colonization of Bifidobacterium spp. and low prevalence of B. infantis among infants of Asian ancestry born in Singapore: insights from the GUSTO cohort study

Background

The loss of ancestral microbes, or the "disappearing microbiota hypothesis" has been proposed to play a critical role in the rise of inflammatory and immune diseases in developed nations. The effect of this loss is most consequential during early-life, as initial colonizers of the newborn gut contribute significantly to the development of the immune system.

Methods

In this longitudinal study (day 3, week 3, and month 3 post-birth) of infants of Asian ancestry born in Singapore, we studied how generational immigration status and common perinatal factors affect bifidobacteria and Bifidobacterium longum subsp. infantis (B. infantis) colonization. Cohort registry identifier: NCT01174875.

Results

Our findings show that first-generation migratory status, perinatal antibiotics usage, and cesarean section birth, significantly influenced the abundance and acquisition of bifidobacteria in the infant gut. Most importantly, 95.6% of the infants surveyed in this study had undetectable B. infantis, an early and beneficial colonizer of infant gut due to its ability to metabolize the wide variety of human milk oligosaccharides present in breastmilk and its ability to shape the development of a healthy immune system. A comparative analysis of B. infantis in 12 countries by their GDP per capita showed a remarkably low prevalence of this microbe in advanced economies, especially Singapore.

Conclusion

This study provides new insights into infant gut microbiota colonization, showing the impact of generational immigration on early-life gut microbiota acquisition. It also warrants the need to closely monitor the declining prevalence of beneficial microbes such as B. infantis in developed nations and its potential link to increasing autoimmune and allergic diseases.

Infant wheezing and prenatal antibiotic exposure and mode of delivery: a prospective birth cohort study

Introduction: Assessments on whether prenatal antibiotic exposure and mode of delivery increase the risk of wheezing in infants and toddlers are inconsistent. Our goal is to evaluate the association between prenatal antibiotic use and Cesarean section with three subtypes of wheezing in infancy.Methods: An ongoing prospective three generations cohort study provides data on prenatal antibiotic use and mode of delivery. Respective questionnaire data was used to distinguish three subtypes of wheezing: any wheezing, infectious wheezing, and noninfectious wheezing. Repeated measurements of wheezing at 3, 6, and 12 months were analyzed using generalized estimation equations. Latent transition analysis assessed patterns of infant wheezing development in the first year of life.Results: The prevalence of any wheezing was highest at 12 months (40.1%). The prevalence of infectious wheezing was higher (3 months 23.8%, 6 months 33.5%, 12 months 38.5%) than of noninfectious wheezing (3 months 13.0%, 6 months 14.0%, 12 months 11.1%). About 11-13% of children had both infectious and noninfectious wheezing at 3, 6, and 12 months (3 months 10.7%, 6 months 13.9%, 12 months 13.1%). Children born via Cesarean section have approximately a 70-80% increase in the risk of any wheezing (RR = 1.83, 95% CI 1.29-2.60) and of infectious wheezing (RR = 1.72, 95% CI 1.18-2.50).Conclusions: Analyses of infectious and noninfectious wheezing subtypes suggests that children born by Cesarean sections may be more susceptible to infectious wheezing, warranting investigations into microbial factors of infectious wheezing. No significant associations were found between prenatal antibiotic exposure and wheezing types.

Epidemiology, Diagnosis, and Treatment of Atopic Dermatitis in the Developing Countries of Asia, Africa, Latin America, and the Middle East: A Review

Atopic dermatitis (AD), the leading cause of skin-related burden of disease worldwide, is increasing in prevalence in developing countries of Asia, Africa, Latin America, and the Middle East. Although AD presents similarly across racial and ethnic groups as chronic and relapsing pruritic eczematous lesions, some features of the disease may be more or less prominent in patients with darker skin. Despite a similar presentation, consistent diagnostic criteria and consistent treatment guidelines are lacking. Because of these and other challenges, adherence to treatment guidelines is difficult or impossible. Previous studies have stated that many patients with AD receive ineffective or inappropriate care, such as oral antihistamines, oral corticosteroids, or traditional medicines, if they are treated at all; one study showed that approximately one-third of patients received medical care for their dermatologic condition; of those, almost three-quarters received inappropriate or ineffective treatment. In addition, other challenges endemic to developing countries include cost, access to care, and lack of specialists in AD. Furthermore, most of the available diagnostic criteria and treatment guidelines are based on European and North American populations and few clinical trials report the racial or ethnic makeup of the study population. Drug pharmacokinetics in varying ethnicities and adverse effects in different skin physiologies are areas yet to be explored. The objective of this review is to describe the diagnosis, treatment, and management of AD in developing countries in Asia, Africa, Latin America, and the Middle East; to discuss the differences among the countries; and to establish the unmet needs of patients with AD in them. The unmet medical need for treatment of AD in developing countries can be addressed by continuing to train medical specialists, improve access to and affordability of care, and develop new and effective treatments.Funding Pfizer Inc.

Establishment of the nasal microbiota in the first 18 months of life: Correlation with early-onset rhinitis and wheezing

BACKGROUND

Dynamic establishment of the nasal microbiota in early life influences local mucosal immune responses and susceptibility to childhood respiratory disorders.

OBJECTIVE

The aim of this case-control study was to monitor, evaluate, and compare development of the nasal microbiota of infants with rhinitis and wheeze in the first 18 months of life with those of healthy control subjects.

METHODS

Anterior nasal swabs of 122 subjects belonging to the Growing Up in Singapore Towards Healthy Outcomes (GUSTO) birth cohort were collected longitudinally over 7 time points in the first 18 months of life. Nasal microbiota signatures were analyzed by using 16S rRNA multiplexed pair-end sequencing from 3 clinical groups: (1) patients with rhinitis alone (n = 28), (2) patients with rhinitis with concomitant wheeze (n = 34), and (3) healthy control subjects (n = 60).

RESULTS

Maturation of the nasal microbiome followed distinctive patterns in infants from both rhinitis groups compared with control subjects. Bacterial diversity increased over the period of 18 months of life in control infants, whereas infants with rhinitis showed a decreasing trend (P < .05). An increase in abundance of the Oxalobacteraceae family (Proteobacteria phylum) and Aerococcaceae family (Firmicutes phylum) was associated with rhinitis and concomitant wheeze (adjusted P < .01), whereas the Corynebacteriaceae family (Actinobacteria phylum) and early colonization with the Staphylococcaceae family (Firmicutes phylum; 3 weeks until 9 months) were associated with control subjects (adjusted P < .05). The only difference between the rhinitis and control groups was a reduced abundance of the Corynebacteriaceae family (adjusted P < .05). Determinants of nasal microbiota succession included sex, mode of delivery, presence of siblings, and infant care attendance.

CONCLUSION

Our results support the hypothesis that the nasal microbiome is involved in development of early-onset rhinitis and wheeze in infants.

Viruses and bacteria in Th2-biased allergic airway disease

Allergic airway diseases are typically characterized by a type 2-biased inflammation. Multiple distinct viruses and bacteria have been detected in the airways. Recently, it has been confirmed that the microbiome of allergic individuals differs from that of healthy subjects, showing a close relationship with the type 2 response in allergic airway disease. In this review, we summarize the recent findings on the prevalence of viruses and bacteria in type 2-biased airway diseases and on the mechanisms employed by viruses and bacteria in propagating type 2 responses. The understanding of the microbial composition and postinfectious immune programming is critical for the reconstruction of the normal microflora and immune status in allergic airway diseases.

Relationship between all fevers or fever after vaccination, and atopy and atopic disorders at 18 and 36 months

Background

Studies have reported that early febrile episodes and febrile episodes with infections are associated with a decreased risk of developing atopy.

Objective

To examine further the association between presence of and number of febrile episodes are with atopy and atopic diseases and if there was a difference between all fevers and fever after vaccination.

Methods

We studied 448 infants in a Singapore mother-offspring cohort study (Growing Up in Singapore Towards Healthy Outcomes) which had complete data for the exposures and outcomes of interest. Fever was defined as more than 38.0℃ and was self-reported. The presence of and number of febrile episodes were examined for association with outcome measures, namely parental reports of doctor-diagnosed asthma and eczema, and rhinitis, which was evaluated by doctors involved in the study at 18 and 36 months. These outcomes were considered atopic if there were 1 or more positive skin prick tests.

Results

The presence of all fevers from 0–6 months of age was associated with reduced odds of having atopy at 36 months of age (unadjusted odds ratio [OR], 0.628; 95% confidence interval [CI], 0.396–0.995). The presence of fever after vaccination from 0–24 months of age was associated with reduced odds of having atopy at 36 months of age (OR, 0.566; 95% CI, 0.350–0.915). The presence of all fevers from 0–6 months of age was associated with reduced odds of having atopic eczema at 36 months (OR, 0.430; 95% CI, 0.191–0.970). Fever was associated with increased odds of having doctor-diagnosed asthma and rhinitis.

Conclusion

There was an inverse relationship between the presence of all fevers from 0–6 months of age and the development of atopy and eczema at 36 months of age. Fever after vaccination might be considered a subclinical infection that did not show the same effect in early life.

An independent association of prenatal depression with wheezing and anxiety with rhinitis in infancy

BACKGROUND

Different maternal psychological states during pregnancy have been associated with wheeze-rhinitis-eczema symptoms in children. However, previous studies were limited and it was unclear whether the type of prenatal psychological state was associated with a particular symptom. We examined the association of maternal depression and anxiety during pregnancy with wheeze-rhinitis-eczema symptoms in infancy.

METHODS

In a longitudinal birth cohort (GUSTO) of 1152 mother-child pairs, wheeze-rhinitis-eczema symptoms in the infants during the first year of life were collected by parental report. Maternal depressive and anxiety symptoms were assessed at 26 weeks of gestation using the Edinburgh Postnatal Depression Scale (EPDS) and State Trait Anxiety Inventory (STAI). Logistic regression analyses were performed with adjustment for potential confounders.

RESULTS

An increased risk of wheezing was found in infants of pregnant women with probable depression (EPDS ≥ 15) [odds ratio (OR) = 1.85 (95% confidence interval (CI) 1.10-3.12)], and an increased risk of rhinitis was associated with maternal anxiety [STAI state ≥ 41: OR = 1.42 (95% CI 1.04-1.93); STAI trait ≥ 43: OR = 1.38 (95% CI 1.01-1.88)]. After adjusting for known risk factors for the development of allergic disease, these associations remained significant [EPDS ≥ 15: adjusted OR = 2.09 (95% CI 1.05-4.19); STAI state ≥ 41: adjusted OR = 1.82 (95% CI 1.17-2.82); STAI trait ≥ 43: adjusted OR = 1.70 (95% CI 1.10-2.61)]. However, maternal psychological states were not associated with infantile eczema.

CONCLUSION

This study suggests that there may be an independent effect of prenatal depression on wheezing and anxiety on rhinitis in infancy.

Treatment of Childhood Atopic Dermatitis and Economic Burden of Illness in Asia Pacific Countries

Atopic dermatitis (AD) is a common chronic inflammatory skin condition in children. In Asia, the prevalence of AD is increasing, which is largely attributed to environmental and socioeconomic factors including family income, parental education, lifestyle and metropolitan living. Current clinical guidelines recommend a stepped approach in the management of eczema in children, with treatment steps tailored to the severity of the eczema. To address the skin barrier dysfunction, skin hydration and the application of emollients is essential. There is evidence supporting the use of bleach baths as an antimicrobial therapy against Staphylococcus aureus. In patients in whom topical treatment fails, wet wrap therapy may be considered as a treatment option before considering systemic therapies. In the second part of this article, the economic burden of AD is addressed. AD not only negatively impacts the child's quality of life but also that of the whole family and is associated with a burden on health-care costs and society. AD in an infant will lead to frequent additional visits to the pediatrician, to additional and partially expensive treatment costs and, in rare cases, to hospitalization. It is thus of utmost importance to define efficient strategies to not only treat AD but also to decrease the risk of developing the disease.

Clinical manifestation and sensitization of allergic children from Malaysia

BACKGROUND

An epidemiological rise of allergic diseases in developing countries raises new challenges. Currently a paucity of data exists describing allergy symptomology and sensitization to common food and aeroallergens in young children from developing countries.

OBJECTIVE

To compare changes in symptomology, food allergen sensitization and aeroallergen sensitization in a cross-sectional study of children <2 years and 2-10 years.

METHODS

A total of 192 allergic children (aged <2 years, 35 children; aged 2-10 years, 157 children) underwent specific IgE (>0.35 kU/L) to common food (egg white, cow's milk, cod fish, wheat, peanut, soya, peanut, and shrimp) and house dust mites (Dermatophagoides pteronyssinus and Blomia tropicalis).

RESULTS

In children <2 years, atopic dermatitis (65.7%) was the most common symptom whereas in children 2-10 years it was rhinoconjunctivitis (74.5%). Higher sensitization rate to eggs (p < 0.01) and cow's milk (p = 0.044) was seen in <2 years group when compared to the 2-10 years group, but no significant differences for shrimp (p = 0.29), wheat (p = 0.23) and soya (p = 0.057). Interestingly, sensitization to peanut (p = 0.012) and fish (p = 0.035) was significantly decreased in the 2-10 years group. Sensitization to house dust mites (p < 0.01) dramatically increased in the older children.

CONCLUSION

Our study supports concept of atopic march from a developing country like Malaysia.

Rhinitis in the first 18 months of life: exploring the role of respiratory viruses

BACKGROUND

Rhinitis is common in early childhood, but allergic rhinitis is considered a later manifestation of the atopic march. This study aimed to evaluate rhinitis (allergic and non-allergic) in the first 18 months of life, its link with other atopic manifestations and the role of respiratory viruses.

METHODS

Subjects (n = 1237) of the Singapore GUSTO birth cohort were followed up quarterly until 18 months of age with questionnaires to screen for rhinitis symptoms lasting at least 2 wk and with monthly calls to positive subjects to detect prolonged/recurrent rhinitis symptoms (total duration ≥ 4 wk). Anterior nasal swabbing for molecular-based virus detection was conducted during these visits and near (within a month) rhinitis episodes. Skin prick testing to common environmental and food allergens was conducted at the 18 month visit.

RESULTS

Prolonged/recurrent rhinitis was significantly associated with history of parental atopy (mother: aOR = 2.17; father: aOR = 1.82) and atopic comorbidities of eczema (aOR = 2.53) and wheeze (aOR = 4.63) (p < 0.05), though not with allergen sensitization. Although the frequency of nasal respiratory virus detection during scheduled quarterly visits did not differ between prolonged/recurrent rhinitis and matched controls (p > 0.05), virus detection was higher in swabs obtained within a month following rhinitis episodes in prolonged/recurrent rhinitis subjects compared with scheduled visits (adjusted p = 0.04).

CONCLUSIONS

Based on the duration of rhinitis symptoms, this study defined a subset of early childhood rhinitis which was associated with atopic predisposition and comorbidities. Persistent respiratory viral shedding may contribute to the symptomatology. Whether this entity is a precursor of subsequent childhood allergic rhinitis will require longer follow-up.

Long-term follow-up of de novo allergy in pediatric liver transplantation--10 yr experience of a single center

We conducted a study to clarify the incidence, clinical course, and risk factors of de novo allergies after liver transplantation. Ninety-three patients who had been followed longer than one yr and who had no previous allergy history were included. Forty-two patients (45.2%) developed de novo allergy. Of them, food allergy developed in 35 (37.6%). Respiratory allergy was observed in three (3.2%), and a patient (1.1%) had drug allergy. Fifty-two (55.9%) of the 93 patients developed eosinophilia. The median age of patients with de novo allergy was 15 months (IR 11.3-20 months). De novo allergy developed five months after liver transplantation (IR 2.3-9.5 months) and lasted for 16 months (IR 8-34.5 months). Younger age at liver transplantation displayed statistically significant differences in development of allergy between allergy and non-allergy groups. Twenty-nine (69.0%) patients improved from allergy during the follow-up period. No patient with de novo gastrointestinal allergy progressed to any respiratory allergy such as asthma. Older age at transplantation, EBV non-risk, and CMV non-risk had statistical significance in allergy improvement. Younger age at transplant predisposes to the development of allergy, while improvement of allergy is achieved more in older age.

Halting the allergic march

The prevalence of childhood allergic diseases, such as allergic asthma, allergic rhinitis, and atopic dermatitis, has increased exponentially. In Singapore, the prevalence of asthma at all ages exceeds 20%, and around 50% of Singaporean children show features of an underlying allergy. The exact environmental causes for the increase of allergic diseases have not yet been identified, but most researchers agree that a decreased bacterial load in young children may be one of the reasons for the increase. However, the causes of allergy are multiple, and the development of an allergic disease is the result of complex interactions between genetic constitution and environmental factors. In this review article, different aspects of allergic sensitization are covered, including prenatal and postnatal sensitization. The phenomenon of the "allergic march" (switching from one clinical expression of allergy to another) and its underlying mechanisms are discussed. The last part of this review article is on prevention and treatment of allergic diseases, including the role of bacterial products (probiotics, prebiotics, and synbiotics) and the role of immunotherapy, including sublingual immunotherapy.

The methodology of the GUSTO cohort study: a novel approach in studying pediatric allergy

Growing Up in Singapore Towards healthy Outcomes (GUSTO) is Singapore's largest birth cohort study to date. The main aim of GUSTO is to evaluate the role of developmental factors in the early pathways to metabolic compromise. Detailed data is collected for a range of environmental exposures in the parents and offspring, and allergic disorders are among a number of outcomes assessed in infancy and childhood. Under the Allergy domain of GUSTO, this integrated study will describe the epidemiology of allergic manifestations and different phenotypes in the Asian context and help shed light on the association of metabolic disease to allergy. Epigenetic mechanisms and associations with other childhood disorders will also be explored. The aim of this report is to focus on methodology of GUSTO, and to suggest similar approaches (i.e., integrated cohort studies on pediatric allergy) worldwide. Recruitment commenced in 2009 with a cohort of 1,163 pregnant mothers in their first trimester. The mothers and children were followed throughout pregnancy and follow-up will continue until the child reaches 3 years of age. Preliminary results showed that 39.8% of the mothers had a personal history of having at least one allergic disease, which included asthma, eczema and allergic rhinitis. Further data collection and analyses are still ongoing. Allergy is a complex spectrum of disorders with numerous poorly-understood aspects. The ongoing GUSTO cohort study, with its longitudinal design and multi-disciplinary nature, may provide new insights into developmental influences on allergy. As a Singapore-based study, it will be the first integrated allergy cohort in Southeast Asia, of which recruitment started during pregnancy.

Rhinitis in children less than 6 years of age: current knowledge and challenges

Rhinitis is a disease of the upper airway characterized by runny and/or blocked nose and/or sneezing. Though not viewed as a life threatening condition, it is also recognized to impose significant burden to the quality of life of sufferers and their caretakers and imposes an economic cost to society. Through a PubMed online search of the literature from 2006 to September 2011, this paper aims to review the published literature on rhinitis in young children below the age of 6 years. It is apparent from epidemiology studies that rhinitis in this age group is a relatively common problem. The condition has a heterogenous etiology with classification into allergic and non-allergic rhinitis. Respiratory viral infections may play a role in the pathogenesis of long standing rhinitis, but definitive studies are still lacking. Treatment guidelines for management are lacking for this age group, and is a significant unmet need. Although the consensus is that co-morbidities including otitis media with effusion, adenoidal hypertrophy and asthma, are important considerations of management of these children. Pharmacotherapy is limited for young children especially for those below the age of 2 years. This review underscores the lack of understanding of rhinitis in early childhood and therefore the need for further research in this area.

Associations between home dampness and presence of molds with asthma and allergic symptoms among young children in the tropics

Existing literature has shown that home dampness increases indoor mold burden and is associated with increased allergic symptoms among young children in temperate environments. There is no report of any studies of similar nature in the tropics where conditions are characterized typically by high temperatures and humidity with rainfall throughout the year. To evaluate if there are associations between the prevalence of current asthma and allergic symptoms in young children (age 1.5-6 yr) with dampness and indoor mold in children's bedrooms in a tropical environment. A cross-sectional study adopting an expanded and modified ISAAC--International Study on Asthma and Allergies in Children--questionnaire for the evaluation of asthma and allergies was conducted on 6794 children (4759 responded--70%) attending 120 randomly selected daycare centers. Specific information on demographics, home dampness, and the visible presence of indoor molds were obtained. The prevalence ratios (PR) and 95% confidence interval (CI) were determined by Cox proportional hazard regression model with assumption of a constant risk period as recommended for cross-sectional studies. The calculated PRs were controlled for age, gender, ethnicity, socio-economic status, type of housing, maternal and paternal atopy, respiratory infections, environmental tobacco smoke (ETS) exposure, and food allergy. After adjusting for potential confounding effects, home dampness was observed to be significantly associated with current symptoms of rhinoconjunctivitis (adjusted PR 1.53, 95% CI: 1.00-2.33). The visible presence of mold was significantly associated with current symptoms of rhinitis (PR 1.55, 95% CI: 1.16-2.07) and rhinoconjunctivitis (PR 2.38, 95% CI: 1.51-3.75). Indoor dampness and mold in children's bedroom are important risk factors associated with allergic symptoms in young children in Singapore.