Timing of infection and development of wheeze, eczema, and atopic sensitization during the first 2 yr of life: the KOALA Birth Cohort Study

Prenatal Maternal Risk Factors Contributing to Atopic Dermatitis: A Systematic Review and Meta-Analysis of Cohort Studies

BACKGROUND

The gestational risk factors predispose to the manifestation of early childhood atopic dermatitis (AD).

OBJECTIVE

We evaluated the association between modifiable and non-modifiable gestational and prenatal risk factors that affect the AD prevalence in children.

METHODS

We performed the systematic review and meta-analysis of cohort studies (n=27) in PubMed and EMBASE (2000~2021). A meta-analysis was performed using random-effects models to estimate pooled odds ratios (OR) or hazard ratio (HR). We performed a systematic review according to Preferred Reporting Item for Systematic Review and Meta-Analyses (PRISMA) guidelines and summarized cohort studies investigating gestational and prenatal risk factor those predispose to AD in off spring. Leading modifiable and non-modifiable were identified through ORs. Meta-analysis using the random effect model was also conducted to provide an overall estimate for several significant factors.

RESULTS

Among the non-modifiable risk factors gestational diabetes (7.2, 95% confidence interval [CI]: 1.4~34.5), maternal history of allergy (2.14, 95% CI: 1.54~2.97) and prenatal history of eczema (2.46, 95% CI: 1.0~5.8) were found as major determining risk factors in early manifestation of AD in children. Further, maternal exposure to industrial products (1.89, 95% CI: 1.10~3.16), exposure to antibiotics during pregnancy (3.59, 95% CI: 1.19~10.85) and passive smoking during pregnancy (2.60, 95% CI: 1.11~6.1) are leading causes of early AD manifestation.

CONCLUSION

Conclusively, both genetic and environmental factors play a pivotal role in early manifestation of AD. The better managing the environmental factors during gestational phase to the least can help curtail the prevalence of AD in children.

Breastfeeding and wheeze-related outcomes in high-risk infants: A systematic review and meta-analysis

BACKGROUND

The risk of wheezing is high in infancy and is heightened in infants with a family history of asthma/atopy. The role of breastfeeding in influencing respiratory health for these high-risk infants is unclear.

OBJECTIVES

To systematically appraise evidence for the association between breastfeeding and wheeze incidences and severity in high-risk infants.

METHODS

Studies identified through electronic databases and reference lists were eligible if they assessed breastfeeding and respiratory outcomes in infants with a family history of asthma/atopy. The primary outcome was wheeze incidences in the first year of life. Secondary outcomes were wheeze incidences in the first 6 months of life, indicators of wheeze severity (recurrent wheeze, health-care utilization, and medication use), and other wheeze-related outcomes [bronchiolitis, pneumonia, croup, and incidence of lower respiratory tract infection (LRTI)] up to 12 months old. Meta-analyses were conducted where possible.

RESULTS

Of 1843 articles screened, 15 observational studies met the inclusion criteria. Breastfeeding was associated with 32% reduced odds of wheezing during the first year of life (ever vs. never: OR, 0.68; 95% CI: 0.53, 0.88; n = 9 studies); this association was even stronger in the first 6 months (OR, 0.45; 95% CI: 0.27, 0.75; n = 5 studies). Breastfeeding for a "longer" versus "shorter" time (approximately longer vs. shorter than 3 months) was associated with 50% reduced odds of wheezing at the age of 6 months (OR, 0.50; 95% CI: 0.39, 0.64; n = 3 studies).

CONCLUSIONS

Breastfeeding was associated with reduced odds of wheezing in high-risk infants, with the strongest protection in the first 6 months. More research is needed to understand the impact of breastfeeding intensity on wheezing and to examine additional respiratory outcomes, including wheeze severity. This review was registered at PROSPERO as CRD42019118631.

The Role of the Environmental Risk Factors in the Pathogenesis and Clinical Outcome of Atopic Dermatitis

Atopic dermatitis (AD) prevalence is rising worldwide. Literature data suggest the incidence of AD in developing countries is gradually getting close to that of developed ones, in which AD affects 20% of the paediatric population. Such an increment, associated with significant variations in prevalence among the various countries, underlines the importance of environmental factors in the disease onset. Among these, great importance is given to hygiene, intestinal microbiota, exposure to bacterial endotoxins, outdoor living with contact to animals, atmospheric pollution, weather, and diet. Genetic (alteration of the skin barrier function) as well as immunologic factors concur with the environmental ones. Only the systematical study of all these elements can best elucidate AD epidemiology.

[Recurrent wheezing: prevalence and associated factors in infants from Buenos Aires City, Argentina]

BACKGROUND

The episodes of bronchial obstruction at early age constitute a frequent problem in Pediatrics. The aim of this study was to evaluate the prevalence of recurrent wheezing in infants in Buenos Aires City, as well as to identify any associated factors.

METHODS

Cross-sectional study performed from 2011 to 2012 in the Children Hospital Ricardo Gutiérrez, Buenos Aires City, as part of the International Study of Wheezing in Infants. A validated questionnaire was applied to parents of infants aged between 12 and 15 months. The prevalence of wheezing, mostly the recurrent episodes (three or more), and their probable associated factors were evaluated. Data were statistically analyzed with χ², Fisher's test, binary and logistics multiple regression analysis. The significance level was 0.05.

RESULTS

Over 1063 infants, 58.9% (confidence interval (CI) 95% 55.9-61.9) presented at least one episode of wheezing and 26.3% (CI95% 23.8-29.9) three or more episodes (recurrent wheezing). Risk factors associated to wheezing were male gender (p=0.001), six or more episodes of cold during the first year of life (p <0.0001), age at first cold <4 months (p <0.0001); pneumonia (p <0.0001) and smoking during pregnancy (tobacco) (p=0.01). For recurrent wheezing, risk factors we considered as six or more episodes of cold during the first year of life (p <0.0001), early (< 4 month of age) onset wheezing (p <0.0001) and nocturnal wheezing (p <0.0001).

CONCLUSIONS

The prevalence of recurrent wheezing among infants in Buenos Aires Ciy was high (26.3%). Some identified associated factors can be preventable.

Risk factors for recurrent wheezing in the first year of life in the city of Córdoba, Argentina

BACKGROUND

Wheezing is a very common respiratory symptom in infants. The prevalence of wheezing in infants, conducted in developed countries shows prevalence rates ranging between 20% and 30%. However, we do not know the risk factors in our population of wheezing infants.

METHODS

A standardised written questionnaire (WQ-P1-EISL) in infants between 12 and 18 months of age residing in the city of Cordoba was used; population/sample included 1031 infants. Recurrent wheezing (RW) was defined as three or more episodes of wheezing reported by the parents during the first 12 months of life. Data obtained were coded in Epi-Info™ (version 7) and statistically analysed with SPSS (version 17.5) software in Spanish. Parametric tests (one-way ANOVA) were performed for identifying significantly associated variables.

RESULTS

The prevalence of wheezing infants was 39.7%; recurrent wheezing 33%; and severe wheezing 14.7%; 13.7% had pneumonia before the first year and of these 6.3% were hospitalised, multiple variables as risk factors for wheezing were found such as: >6 high airway infections and bronchiolitis in the first three months of life, smokers who smoke in the home among other risk factors and protective factors in those who have an elevated socioeconomic status.

CONCLUSION

It is known that persistent respiratory problems in children due to low socioeconomic status is a risk factor for wheezing, pneumonia and could be a determining factor in the prevalence and severity of RW in infants. Research suggests that there are areas for improvement in the implementation of new educational strategies.

Timing of routine infant vaccinations and risk of food allergy and eczema at one year of age

BACKGROUND

Epidemiological evidence suggests that routine vaccinations can have nontargeted effects on susceptibility to infections and allergic disease. Such effects may depend on age at vaccination, and a delay in pertussis vaccination has been linked to reduced risk of allergic disease. We aimed to test the hypothesis that delay in vaccines containing diphtheria-tetanus-acellular pertussis (DTaP) is associated with reduced risk of food allergy and other allergic diseases.

METHODS

HealthNuts is a population-based cohort in Melbourne, Australia. Twelve-month-old infants were skin prick-tested to common food allergens, and sensitized infants were offered oral food challenges to determine food allergy status. In this data linkage study, vaccination data for children in the HealthNuts cohort were obtained from the Australian Childhood Immunisation Register. Associations were examined between age at the first dose of DTaP and allergic disease.

RESULTS

Of 4433 children, 109 (2.5%) received the first dose of DTaP one month late (delayed DTaP). Overall, delayed DTaP was not associated with primary outcomes of food allergy (adjusted odds ratio (aOR) 0.77; 95% CI: 0.36-1.62, P = 0.49) or atopic sensitization (aOR: 0.66; 95% CI: 0.35-1.24, P = 0.19). Amongst secondary outcomes, delayed DTaP was associated with reduced eczema (aOR: 0.57; 95% CI: 0.34-0.97, P = 0.04) and reduced use of eczema medication (aOR: 0.45; 95% CI: 0.24-0.83, P = 0.01).

CONCLUSIONS

There was no overall association between delayed DTaP and food allergy; however, children with delayed DTaP had less eczema and less use of eczema medication. Timing of routine infant immunizations may affect susceptibility to allergic disease.

Acute Otitis Media and Other Complications of Viral Respiratory Infection

BACKGROUND

Viral upper and lower respiratory tract infections (URI, LRI) are common in infants. We determined the prevalence of viral URI and its complications, including acute otitis media (AOM) and LRI, and assessed the effect of bacterial-viral interactions, and genetic and environmental risks on AOM development.

METHODS

Healthy infants were enrolled from near birth and followed to the first episode of AOM up to 12 months of age. Nasopharyngeal specimens were collected at monthly intervals (months 1-6, 9) and during viral URI episodes for bacterial culture and viral polymerase chain reaction studies. Subjects were followed closely for AOM development.

RESULTS

A total of 367 infants were followed for 286 child-years; 887 URI (305 infants) and 180 AOM episodes (143 infants) were documented. Prevalence of URI, LRI, and AOM in the first year was 3.2, 0.25, and 0.67 per child-year, respectively. Cumulative AOM incidence by ages 3, 6, and 12 months was 6%, 23%, and 46%. Infants with and without AOM had 4.7 and 2.3 URI episodes per child-year, respectively (P < .002). Pathogenic bacterial colonization rates by month were significantly higher in infants with AOM (P < .005). Breastfeeding reduced both URI and AOM risks (P < .05). Significant bacterial-viral interactions occurred with Moraxella catarrhalis and a variety of respiratory viruses and altered URI and AOM risks.

CONCLUSIONS

Almost half of infants experienced AOM by age 1. Important AOM risk factors included frequent viral URI, pathogenic bacterial colonization, and lack of breastfeeding. Bacterial-viral interactions may play a significant role in AOM pathogenesis and deserve further investigation.

Historic overview of allergy research in the Netherlands

Research in allergy has a long history in the Netherlands, although the relation with immunology has not always been appreciated. In many aspects Dutch researchers have made major contribution in allergy research. This ranges from the first characterization of house dust mite as an important allergen, the first characterization of human Th2 and Th1 T cell clones, to the development of diagnostic test systems. In this overview Aalberse and Knol have made an overview of the major contributions of Dutch immunologists in allergy.

Systematic review and meta-analyses: fever in pregnancy and health impacts in the offspring

BACKGROUND AND OBJECTIVE

Fever during pregnancy has been suspected to harm the developing fetus. However, until now, no systematic analysis of the available evidence has been undertaken to assess the impact of maternal fever on health outcomes in the child. The goal of this study was to systematically review evidence from epidemiologic studies on adverse health outcomes of the offspring in relation to exposure to maternal fever during pregnancy.

METHODS

Systematic searches in PubMed, Web of Science, and the Cochrane Library were performed by using Medical Subject Headings, Boolean operators, and truncation, and references of references were reviewed. Cohort and case-control studies addressing health outcomes of prenatal fever exposure in humans were eligible for inclusion. Studies with no direct reference to fever, studies in selected populations (eg, preterm births), and studies published before 1990 were excluded.

RESULTS

The available literature supported an increased risk of adverse offspring health in association with fever during pregnancy. The strongest evidence was available for neural tube defects, congenital heart defects, and oral clefts, in which meta-analyses suggested between a 1.5- and nearly 3-fold increased risk with fever exposure in the first trimester. We did not find strong evidence of a dose-response relationship, but there was some evidence that antipyretic medications may have a protective effect when used in relation to febrile episodes.

CONCLUSIONS

We found substantial evidence to support the contention that maternal fever during pregnancy may negatively affect offspring health. The harmful effects seemed to cover both short- and longer-term health outcomes; however, for several outcomes, the evidence was insufficient to judge any association.

New insights into the epidemiology of childhood atopic dermatitis

There is a growing desire to explain the worldwide rise in the prevalence of atopic dermatitis (AD). Trend data on the burden of AD suggest that the picture in the developing world may soon resemble that of wealthier nations, where AD affects over 20% of children. This, combined with significant variations in prevalence within countries, emphasizes the importance of environmental factors. Many hypotheses have been explored, from the modulation of immune priming by hygiene, gut microbiota diversity, and exposure to endotoxins through farm animals to the effects of pollution, climate, and diet. The discovery of the filaggrin skin barrier gene and its importance in AD development and severity has brought the focus on gene-environment interactions and the identification of environmental factors that impact on skin barrier function. This article reviews our current understanding of the epidemiology of AD, with an emphasis on the findings reported in the international literature over the last 5 years.

Perinatal influences on the development of asthma and atopy in childhood

BACKGROUND

In most children with asthma and atopy, onset of disease occurs early in life, indicating a crucial role of in utero and early childhood environment. However, only a small part of this burden of disease established early in life has been explained.

OBJECTIVE

To examine the effects of early environmental exposures on the development of asthma and atopy within the setting of an affluent urban population.

METHODS

The authors followed 526 German children from birth to 5 years of age. Parental interviews in pregnancy and then yearly assessed the health of the child and environmental characteristics. Endotoxin and allergens in house dust were measured at 3 months. Atopic sensitization was assessed at 1 and 5 years.

RESULTS

In atopic mothers, acute atopic symptoms during pregnancy were associated with increased risk of early atopic dermatitis (adjusted odds ratio [aOR] 1.74, 95% confidence interval [CI] 1.00-3.02) and allergic rhinitis at 5 years (aOR 2.11, 95% CI 1.01-4.41). Further, maternal illnesses during pregnancy (ie, repeated common colds) increased the risk of asthma at 5 years (aOR 2.31, 95% CI 1.12-4.78). Endotoxin in the child's mattress was inversely associated with atopic sensitization (aOR 0.79, 95% CI 0.64-0.97) and asthma (aOR 0.71, 95% CI 0.55-0.93). A contrasting effect of early endotoxin and mite exposure was observed for mite sensitization: mite exposure increased the risk of mite sensitization at 5 years (aOR 1.30, 95% CI 1.11-1.53), whereas endotoxin exposure was inversely associated with mite sensitization (aOR 0.73, 95% CI 0.57-0.95).

CONCLUSION

Factors affecting the in utero environment, such as maternal atopy and infections, and bacterial exposure in pregnancy or early life may act as immunomodulators enhancing or inhibiting the development of asthma and atopy in childhood.

Risk factors associated with wheezing in infants

OBJECTIVE

to identify possible risk factors associated with wheezing in infants (12-15 months-old) in the state of Mato Grosso, Brazil.

METHODS

this was a cross-sectional study performed by applying a standardized written questionnaire from the international study on wheezing in infants (Estudio Internacional de Sibilancia en Lactantes - EISL), phase 3. Parents and/or guardians of infants were interviewed at primary health care clinics or at home from August of 2009 to November of 2010. Factors associated to wheezing were studied using bivariate and multivariate analysis (using the Statistical Package for Social Sciences [SPSS] v.18.0), and expressed as odds ratios (OR) and 95% confidence intervals (95% CI).

RESULTS

the written questionnaire was answered by 1,060 parents and/or guardians. The risk factors for wheezing were: history of asthma in the family [mother (OR = 1.62; 95% CI = 1.07-2.43); father (OR = 1.98; 95% CI = 1.22-3.23); siblings (OR = 2.13; 95% CI = 1.18-3.87)]; history of previous pneumonia (OR = 10.80; 95% CI = 4.52-25.77); having had more than six upper respiratory tract infections (URTIs) (OR = 2.95; 95% CI = 2.11-4.14); having had first URTI before the third month of life (OR = 1.50; 95% CI = 1.04-2.17); living in a moderately polluted area (OR = 1.59; 95% CI = 1.08-2.33); paracetamol use for URTI (OR = 2.13; 95% CI = 1.54-2.95); and antibiotic use for skin infection (OR = 2.29; 95% CI = 1.18-4.46).

CONCLUSIONS

the study of risk factors for wheezing in the first year of life is important to help physicians identify young children at high risk of developing asthma and to improve public health prevention strategies in order to reduce the morbidity of wheezing in childhood.

Allergic airway diseases in childhood - marching from epidemiology to novel concepts of prevention

In the past years, a wide range of epidemiological, clinical, and experimental studies have produced remarkable advances in the field of respiratory allergies in childhood. By the recent investigations on epidemiological trends, risk factors, and prevention of asthma and allergic rhinitis, various exiting concepts have been challenged, and novel innovative approaches have been developed. Pediatric Allergy and Immunology (PAI), with a number of highly relevant contributions between 2010 and 2012, has become an important forum in this area. The prevalence of asthma in some developed countries may have reached a plateau, while in developing countries, where the prevalence was previously low, allergic diseases are still on the increase. A wide array of risk and protective factors, including hygiene, infections, outdoor and indoor air pollution, allergen exposure, breast-feeding practices, nutrition, and obesity, play a multifaceted role in shaping the observed worldwide trends of respiratory allergies. Under the guidance of recent research, prediction and prevention strategies in the clinical practice are progressively changing, the focus moving away from avoidance of allergen exposure and toward tolerance induction.

Early life exposures: impact on asthma and allergic disease

PURPOSE OF REVIEW

To identify and discuss recent studies relating prenatal and early-life environmental exposures to the development of asthma and allergic disease.

RECENT FINDINGS

New studies show that prenatal and early-life stress can alter infant immune profiles, increasing risk for asthma and allergy. Mounting evidence implicates indoor and outdoor air pollution in the origins of allergic disease, while Vitamin D intake and a Mediterranean diet may be protective. The role of early-life fever and infection remain controversial, with recent studies yielding conflicting results and new evidence indicating that previous studies may have been confounded. New studies are increasingly focused on environmental 'imprinting' of the infant gut microbiota, which is a critical determinant of immune system development. Early exposures impacting the intestinal microbiota include mode of delivery, infant diet, and use of antibiotics - factors that are also associated with childhood asthma and allergic disease.

SUMMARY

This overview highlights environmental exposures during the in-utero and ex-utero time periods that are potential stimuli for the early programming of asthma and allergy. Special consideration is given for the potential role of intestinal microbiota. Future studies in this field promise to inform health policy and intervention strategies for the prevention of asthma and allergic disease.

Pregnancy exposures and risk of childhood asthma admission in a population birth cohort

BACKGROUND

There is increasing interest in the potential for in utero exposures to affect the risk of asthma. We used population data to explore the associations between perinatal conditions and the risk of hospital admission with asthma between the 2nd and 5th birthday.

METHODS

The study population was 240,511 singleton infants born during 2001-2003. Birth records and longitudinally linked hospital admissions were used to identify asthma admissions and to model potential risk factors.

RESULTS

A total of 7245 children (3.0%) had one or more childhood admissions with asthma. In utero infectious exposures associated with childhood asthma were maternal antenatal admission with a urinary tract infection (UTI) [adjusted odds ratio (aOR) = 1.49, 95% confidence interval (1.23-1.79)] and pre-term pre-labor rupture of membranes (PROM) [aOR = 1.23 (1.04-1.45)]. There was no evidence that gestational age at time of first antenatal UTI admission (<28, ≥ 28 wks) affected the risk of asthma (homogeneity test p = 0.6). Pre-term birth was a risk factor for asthma admission, with the risk decreasing by 5.3% with each extra week of gestation. Autumn and winter conceptions were associated with an increased risk of childhood asthma admission: winter aOR = 1.15 (1.08-1.23), autumn aOR = 1.09 (1.02-1.16).

CONCLUSIONS

As in utero exposure to both UTI and PROM carry an increased risk of childhood asthma admission, this suggests that the immune system response generally is the relevant factor rather than a specific organism. The season-associated risk is consistent with early pregnancy exposures such as the winter flu season or low vitamin D.

The allergic march: can we prevent allergies and asthma?

The allergic march is a progression of atopic disease from eczema to asthma, and then to allergic rhinoconjunctivitis. It appears to be caused by a regional allergic response with breakdown of the local epithelial barrier that initiates systemic allergic inflammation. Genetic and environmental factors predispose to developing the allergic march. There are data to support 4 possible interventions to prevent the allergic march from progressing to asthma: (1) supplements of dietary probiotics, (2) exclusive breast feeding during the first few months of life, or, alternatively (3) use of extensively hydrolyzed infant formulas, (4) treatment with inhalant allergen immunotherapy by either subcutaneous or sublingual methods.