Impaired fetal growth decreases the risk of childhood atopic eczema: a Swedish twin study

Preterm birth reduces the risk of IgE sensitization up to early adulthood: A population-based birth cohort study

BACKGROUND

Immunoglobulin E (IgE) sensitization is associated with asthma and allergic diseases. Gestational age influences early immune system development, thereby potentially affecting the process of tolerance induction to allergens.

OBJECTIVE

To study IgE sensitization to common allergens by gestational age from childhood up to early adulthood.

METHODS

Population-based birth cohort, data from the Swedish BAMSE study were used. Allergen-specific IgE antibodies to a mix of common food (fx5) and inhalant (Phadiatop) allergens were analysed at 4, 8, 16 and 24 years. Sensitization was defined as allergen-specific IgE ≥0.35 kU_A /L to fx5 and/or Phadiatop at each time point. Using logistic regression and generalized estimated equations, adjusted odds ratios (aORs) for sensitization in relation to gestational age were calculated. Replication was sought within the Swedish twin study STOPPA.

RESULTS

In BAMSE, 3522 participants were screened for IgE antibodies during follow-up; of these, 197 (5.6%) were born preterm (<37 gestational weeks) and 330 (9.4%) post-term (≥42 weeks). Preterm birth reduced the risk of sensitization to common food and/or inhalant allergens up to early adulthood by 29% (overall aOR = 0.71; 95% CI: 0.52-0.98), and to food allergens specifically by 40% (overall aOR = 0.60; 95% CI: 0.38-0.93). No relation was found between post-term birth and IgE sensitization at any time point. Replication analyses in STOPPA (N = 675) showed similar risk estimates for sensitization to food and/or inhalant allergens (aOR = 0.72; 95% CI: 0.42-1.21), which resulted in a combined meta-analysis aOR = 0.71 (95% CI: 0.54-0.94).

CONCLUSIONS

Our study suggests an inverse association between preterm birth and long-term IgE sensitization.

Prepregnancy BMI, gestational weight gain and risk of childhood atopic dermatitis: A systematic review and meta-analysis

BACKGROUND

Maternal weight before and during pregnancy influences the health of offspring. Several observational studies have investigated a link between the risk of childhood atopic dermatitis (AD) and prepregnancy maternal body mass index (BMI) and gestational weight gain (GWG), but the conclusions of these studies were inconsistent. The aim of this review was to evaluate the association between the risk of childhood AD and prepregnancy maternal BMI and GWG.

METHODS

The PubMed, Embase, Cochrane, Web of Science, and Scopus databases were searched from inception to February 2, 2021. Observational studies investigating the association between the risk of childhood AD and prepregnancy maternal BMI and GWG were included. Fixed- or random-effects models with inverse variance weights were used to calculate pooled risk estimates. Subgroup analysis and sensitivity analysis were used to explore the sources of heterogeneity.

RESULTS

Thirteen studies with a total of 114 485 participants were included. Ten studies reported prepregnancy maternal BMI, and five reported GWG. Maternal underweight was associated with a higher risk of childhood AD (odds ratio [OR] = 1.06; 95% confidence interval [CI], 1.02-1.10). Continuous BMI was not related to childhood AD (OR = 1.00; 95% CI, 0.98-1.02). In comparison with normal GWG, moderate/very high GWG increased the risk of childhood AD (OR = 1.05; 95% CI, 1.02-1.08; OR = 1.13; 95% CI, 1.07-1.19, respectively), while low GWG decreased the risk (OR = 0.92; 95% CI, 0.89-0.96). Excessive GWG relative to recommendations was associated with a higher risk of childhood AD (OR = 1.05; 95% CI, 1.01-1.10), while a lower risk of childhood AD was associated with inadequate GWG relative to recommendations (OR = 0.87, 95% CI: 0.83-0.91).

CONCLUSIONS

Maternal underweight, high GWG, and excessive GWG relative to recommendations are associated with an elevated risk of childhood AD, while low GWG and inadequate GWG relative to recommendations decreased the risk. Weight management before and during pregnancy is encouraged for primary prevention of childhood AD.

Intrauterine Growth Restriction Promotes Postnatal Airway Hyperresponsiveness Independent of Allergic Disease

Introduction: Intrauterine growth restriction (IUGR) is associated with asthma. Murine models of IUGR have altered airway responsiveness in the absence of any inflammatory exposure. Given that a primary feature of asthma is airway inflammation, IUGR-affected individuals may develop more substantial respiratory impairment if subsequently exposed to an allergen. This study used a maternal hypoxia-induced mouse model of IUGR to determine the combined effects of IUGR and allergy on airway responsiveness.

Methods: Pregnant BALB/c mice were housed under hypoxic conditions (10.5% O₂) from gestational day (GD) 11-GD 17.5 (IUGR group; term = GD 21). Following hypoxic exposure, mice were returned to a normoxic environment (21% O₂). A second group of pregnant mice were housed under normoxic conditions throughout pregnancy (Control). All offspring were sensitized to ovalbumin (OVA) and assigned to one of four treatment groups: Control – normoxic and saline challenge; IUGR – hypoxic and saline challenge; Allergy – normoxic and OVA challenge; and IUGR + Allergy – hypoxic and OVA challenge. At 8 weeks of age, and 24 h post-aerosol challenge, mice were tracheostomised for methacholine challenge and assessment of lung mechanics by the forced oscillation technique, and lungs subsequently fixed for morphometry.

Results: IUGR offspring were lighter than Control at birth and in adulthood. Both Allergy and IUGR independently increased airway resistance after methacholine challenge. The IUGR group also exhibited an exaggerated increase in tissue damping and elastance after methacholine challenge compared with Control. However, there was no incremental effect on airway responsiveness in the combined IUGR + Allergy group. There was no impact of IUGR or Allergy on airway structure and no effect of sex on any outcome.

Conclusion: IUGR and aeroallergen independently increased bronchoconstrictor response, but when combined the pathophysiology was not worsened. Findings suggest that an association between IUGR and asthma is mediated by baseline airway responsiveness rather than susceptibility to allergen.

Adverse pregnancy outcomes and risk of later allergic rhinitis-Nationwide Swedish cohort study

BACKGROUND

Perinatal conditions may be associated with future allergic disease; however, data are conflicting and incomplete for childhood allergic rhinitis (AR). The aim of this study was to examine pregnancy outcome (cesarean delivery, preterm birth, low birthweight) and offspring AR as defined by national registers.

METHODS

Nationwide longitudinal cohort study using prospectively recorded register data from 1 059 600 singleton livebirths born in Sweden in 2001-2012. Cox regression adjusted for infant sex and maternal factors (age at delivery, country of birth, parity, smoking, body mass index, and asthma/pulmonary disease) estimated hazard ratios (HRs) for AR during childhood.

RESULTS

During the study period 2001-2013, 22 386 (2.11%) children were diagnosed with AR. AR was more common in infants born through cesarean delivery (2.34%) than in those born vaginally (2.10%) (HR = 1.12; 95% confidence interval [95% CI] = 1.08-1.16). This was equivalent to one extra case of AR in 383 children followed up in our study. AR was also associated with moderately preterm birth (≥32-36 weeks of gestation: HR = 1.12, 95% CI = 1.04-1.20), large for gestational age (HR = 1.05, 95% CI = 1.01-1.10), and low (<7) 5-minute Apgar score (HR = 1.15, 95% CI = 1.02-1.30). Similar risk estimates were obtained when we restricted the outcome to ≥2 hospital-based records of AR. No association was observed between very preterm birth, post-term birth, low birthweight, or small for gestational age and AR.

CONCLUSION

Our study indicates an association between pregnancy outcomes and childhood AR, although observed effect sizes were generally modest.

Relationship between birth weight or fetal growth rate and postnatal allergy: A systematic review

BACKGROUND

Individual susceptibility to allergic diseases is developmentally programmed by early-life exposures. Evidence from preclinical studies suggests that intrauterine growth restriction is protective against later inflammatory responses to allergens.

OBJECTIVE

We sought to evaluate whether prenatal growth affects susceptibility to allergy in human subjects.

METHODS

We systematically searched for relevant studies in 11 databases, including Web of Science, ProQuest, EMBASE, and PubMed. We included only studies that corrected for gestational age or were restricted to full-term infants to separate effects of fetal growth from those of prematurity.

RESULTS

The 42 eligible studies included prospective and retrospective cohort, cross-sectional, and case-control studies. Only 2 studies reported allergic asthma. A birth weight increase of 1 kg was associated with a 44% greater risk of food allergy in children (odds ratio [OR], 1.44; 95% CI, 1.04-1.99; P = .001), a 17% greater risk of ever allergic dermatitis in children (OR, 1.17; 95% CI, 1.04-1.32; P = .008), and a 34% greater risk of ever or current allergic dermatitis in infants up to 2 years of age (OR, 1.34; 95% CI, 1.08-1.68; P = .009). Risks of allergic rhinitis were not associated with birth weight.

CONCLUSIONS

The results of these meta-analyses suggest that intrauterine growth restriction protects against allergic diseases in human subjects consistent with preclinical evidence but that effects might differ between allergic diseases. The strongest evidence is available for infancy and early childhood, and additional studies in older children and adults are needed to determine whether the effects of prenatal growth on each allergic disease persist or differ between those with severe and mild phenotypes.

Asthma, Rhinoconjunctivitis, Eczema, and the Association with Perinatal Anthropometric Factors in Vietnamese Children

Few studies have investigated possible causative and protective factors associated with allergic diseases in resource-limited countries, Southeast Asia. We estimated the current prevalence of asthma, rhinoconjunctivitis, and eczema among 6-year-old children, and identified anthropometric factors associated with asthma, rhinoconjunctivitis and eczema, in South-Central Vietnam. A birth cohort study recruited 1,999 children born at a provincial hospital in Nha Trang, Vietnam between May 2009 and May 2010. A 6-year follow-up survey was conducted where clinical, familial, and environmental information was collected by interviewing caregivers using a standardized form based on the International Study of Asthma and Allergies in Childhood, Phase Three Core and Environmental Questionnaire for 6–7-year-old children. The odds ratios of asthma, rhinoconjunctivitis, and eczema for anthropometric factors were estimated using logistic regression analysis. In total, 1202 children participated in the follow-up survey. The proportions of children who had current asthma, rhinoconjunctivitis, and eczema were 5.1% (95% confidence interval [CI] 3.9–6.5%), 11.5% (9.7–13.4%), and 6.7% (5.3–8.2%), respectively. Low birthweight (adjusted odds ratio 5.12, 95% CI 1.92–13.64) was independently associated with increased risk of eczema. Further studies are necessary to understand the involved mechanism.

Fetal growth and incidence of atopic dermatitis in early childhood: Results of the Ulm SPATZ Health Study

Fetal growth may be a precursory factor in observed association between birthweight and atopic dermatitis (AD), however, recent studies utilizing fetal ultrasound-based data have reported contradictory results. This study aims to clarify previous findings through comprehensive investigation of association between several trimester-specific ultrasound-based anthropometric measures with AD diagnosis by age 3 years. Measurements of 386 newborns in the Ulm SPATZ Health Study were converted into adjusted z-scores categorized as "low" (≤1 SD below mean), "normal," or "high" (≥1 SD above mean). AD cases were defined using parent- or pediatrician-report of physician-diagnosis or clinical diagnosis. Adjusted risk ratios (RR) with 95% confidence intervals (95% CI) were calculated using modified Poisson regression. Compared to normal, both low and high 2^nd trimester abdominal circumference [RR 1.51, (95% CI 1.01; 2.24) and 1.83 (1.21; 2.76)], high 2^nd trimester head- abdominal circumference ratio [1.69 (1.16; 2.48)], and faltering 2^nd to 3^rd trimester [1.59 (1.04; 2.43)] head circumference were associated with greater AD risk. High 3^rd trimester femur length [0.54 (0.31; 0.94)] was associated with lower risk. Using more inclusive exposure cut-points (0.8 SD), lower 1^st trimester crown-rump length was also associated with greater AD risk. Our data suggest several different patterns of fetal growth may be differentially associated with AD.

Relationship between birth weight or fetal growth rate and postnatal allergy: a systematic review protocol

REVIEW QUESTION/OBJECTIVE

The objective of this systematic review is to synthesize the best available evidence on the relationship between size at birth or fetal growth and postnatal allergy. Specifically, this review aims to assess evidence regarding relationships between absolute birth weight at term, birth weight corrected for gestational age, expressed as relative to population or customized growth data, or fetal growth measures and physician-diagnosed or parent- and self-reported postnatal clinical allergic disease (eczema/atopic dermatitis, hay fever/rhinitis, allergic asthma or anaphylaxis).The specific review question is: what is the association between the absolute birth weight at full-term or birth weight relative to population or customized data and corrected for gestational age or direct measures of fetal growth, and physician-diagnosed or parent- and self-reported clinical allergic disease (eczema/atopic dermatitis, hay fever/rhinitis, allergic asthma or anaphylaxis)?

Late-gestation maternal dietary methyl donor and cofactor supplementation in sheep partially reverses protection against allergic sensitization by IUGR

Perinatal exposures are associated with altered risks of childhood allergy. Human studies and our previous work suggest that restricted growth in utero (IUGR) is protective against allergic disease. The mechanisms are not clearly defined, but reduced fetal abundance and altered metabolism of methyl donors are hypothesized as possible underlying mechanisms. Therefore, we examined whether late-gestation maternal dietary methyl donor and cofactor supplementation of the placentally restricted (PR) sheep pregnancy would reverse allergic protection in progeny. Allergic outcomes were compared between progeny from control pregnancies (CON; n = 49), from PR pregnancies without intervention (PR; n = 28), and from PR pregnancies where the dam was fed a methyl donor plus cofactor supplement from day 120 of pregnancy until delivery (PR + Methyl; n = 25). Both PR and PR + Methyl progeny were smaller than CON; supplementation did not alter birth size. PR was protective against cutaneous hypersensitivity responses to ovalbumin (OVA; P < 0.01 in singletons). Cutaneous hypersensitivity responses to OVA in PR + Methyl progeny were intermediate to and not different from the responses of CON and PR sheep. Cutaneous hypersensitivity responses to house dust mites did not differ between treatments. In singleton progeny, upper dermal mast cell density was greater in PR + Methyl than in PR or CON (each P < 0.05). The differences in the cutaneous allergic response were not explained by treatment effects on circulating immune cells or antibodies. Our results suggest that mechanisms underlying in utero programming of allergic susceptibility by IUGR and methyl donor availability may differ and imply that late-gestation methyl donor supplementation may increase allergy risk.

Pre-birth origins of allergy and asthma

Allergy is a chronic disease that can develop as early as infancy, suggesting that early life factors are important in its aetiology. Variable associations between size at birth, a crude marker of the fetal environment, and allergy have been reported in humans and require comprehensive review. Associations between birth weight and allergy are however confounded in humans, and we and others have therefore begun exploring the effects of early life events on allergy in experimental models. In particular, we are using ovine models to investigate whether and how a restricted environment before birth protects against allergy, whether methyl donor availability contributes to allergic protection in IUGR, and why maternal asthma during pregnancy is associated with increased risks of allergic disease in children. We found that experimental intrauterine growth restriction (IUGR) in sheep reduced cutaneous responses to antigens in progeny, despite normal or elevated IgE responses. Furthermore, maternal methyl donor supplementation in late pregnancy partially reversed effects of experimental IUGR, consistent with the proposal that epigenetic pathways underlie some but not all effects of IUGR on allergic susceptibility. Ovine experimental allergic asthma with exacerbations reduces relative fetal size in late gestation, with some changes in immune populations in fetal thymus suggestive of increased activation. Maternal allergic asthma in mice also predisposes progeny to allergy development. In conclusion, these findings in experimental models provide direct evidence that a perturbed environment before birth alters immune system development and postnatal function, and provide opportunities to investigate underlying mechanisms and develop and evaluate interventions.

In utero Programming of Allergic Susceptibility

BACKGROUND

Around 30-40% of the world's population will experience allergy, the most common and earliest-onset noncommunicable disease. With a steady rise in the incidence of allergic disease over recent decades, up to 18% of children will suffer a respiratory, food or skin allergy before their 18th birthday. There is compelling evidence that the risk of developing allergy is influenced by early life events and particularly in utero exposures.

METHODS

A comprehensive literature review was undertaken which outlines prenatal risk factors and potential mechanisms underlying the development of allergy in childhood.

RESULTS

Exposures including maternal cigarette smoking, preterm birth and Caesarean delivery are implicated in predisposing infants to the later development of allergy. In contrast, restricted growth in utero, a healthy maternal diet and a larger family size are protective, but the mechanisms here are unclear and require further investigation.

CONCLUSION

To ameliorate the allergy pandemic in young children, we must define prenatal mechanisms that alter the programming of the fetal immune system and also identify specific targets for antenatal interventions.

Heritability and confirmation of genetic association studies for childhood asthma in twins

BACKGROUND

Although the genetics of asthma has been extensively studied using both quantitative and molecular genetic analysis methods, both approaches lack studies specific to the childhood phenotype and including other allergic diseases. This study aimed to give specific estimates for the heritability of childhood asthma and other allergic diseases, to attempt to replicate findings from genomewide association studies (GWAS) for childhood asthma and to test the same variants against other allergic diseases.

METHODS

In a cohort of 25 306 Swedish twins aged 9 or 12 years, data on asthma were available from parental interviews and population-based registers. The interviews also inquired about wheeze, hay fever, eczema, and food allergy. Through structural equation modeling, the heritability of all phenotypes was calculated. A subset of 10 075 twins was genotyped for 16 single nucleotide polymorphisms (SNPs) selected from previous GWAS; these were first tested for association with asthma and significant findings also against the other allergic diseases.

RESULTS

The heritability of any childhood asthma was 0.82 (95% CI 0.79-0.85). For the other allergic diseases, the range was approximately 0.60-0.80. Associations for six SNPs with asthma were replicated, including rs2305480 in the GSDMB gene (OR 0.80, 95% CI 0.74-0.86, P = 1.5*10(-8) ; other significant associations all below P = 3.5*10(-4) ). Of these, only rs3771180 in IL1RL1 was associated with any other allergic disease (for hay fever, OR 0.64, 95% CI 0.53-0.77, P = 2.5*10(-6) ).

CONCLUSION

Asthma and allergic diseases of childhood are highly heritable, and these high-risk genetic variants associated specifically with childhood asthma, except for one SNP shared with hay fever.

Impact of asthma medication and familial factors on the association between childhood asthma and attention-deficit/hyperactivity disorder: a combined twin- and register-based study: Epidemiology of Allergic Disease

BACKGROUND

Asthma and attention-deficit/hyperactivity disorder (ADHD) are prevalent in childhood and may cause functional impairment and stress in families. Previous research supports an association between asthma and ADHD in children, but several aspects of this relationship are unclear.

OBJECTIVE

Our aim was to study whether the association between asthma and ADHD is restricted to either the inattentive or the hyperactive/impulsive symptoms of ADHD, to explore the impact of asthma severity and asthma medication and the contribution of shared genetic and environmental risk factors on the asthma-ADHD relationship.

METHODS

Data on asthma, ADHD, zygosity and possible confounders were collected from parental questionnaires at 9 or 12 years on 20 072 twins through the Swedish Twin Register, linked to the Swedish Medical Birth Register, the National Patient Register and the Prescribed Drug Register. The association between asthma and ADHD, the impact of asthma severity and medication, was assessed by generalized estimating equations. Cross-twin-cross-trait correlations (CTCT) were estimated to explore the relative importance of genes and environment for the association.

RESULTS

Asthmatic children had a higher risk of also having ADHD [odds ratio (OR) 1.53, 95% confidence interval (CI): 1.16-2.02]. The association was not restricted to either of the two dimensions of ADHD. The magnitude of the association increased with asthma severity (OR 2.84, 95% CI: 1.86-4.35) for ≥ 4 asthma attacks in the last 12 months and was not affected by asthma treatment. The CTCTs possibly indicate that the genetic component in overlap of the disorders is weak.

CONCLUSIONS AND CLINICAL RELEVANCE

Childhood asthma, especially severe asthma, is associated with ADHD. Asthma medication seems not to increase the risk of ADHD. Clinicians should be aware of the potential of ADHD in asthma. Optimal asthma care needs to be integrated with effective evaluation and treatment of ADHD in children with co-existing disorders.

Fetal Growth, Obesity, and Atopic Disorders in Adolescence: a Retrospective Birth Cohort Study

BACKGROUND

Developmental status at birth and subsequent obesity have been implicated in the development of childhood atopic dermatitis (AD) and allergic rhinitis (AR).

METHODS

The current study analysed the cohort data of 74 688 junior high school students from a national retrospective birth cohort study in Taiwan. A random 10% sample was selected from singleton livebirths with complete data on the analytical variables of interest. Atopic disorders, including AD and AR, were assessed by questionnaires (International Study of Asthma and Allergies in Childhood). Logistic regression analyses were applied with adjustments for related risk factors.

RESULTS

Among subjects mainly 13-15 years of age, the estimated prevalence was 7.6% for AD and 22.4% for AR. While the role of fetal growth in allergic disorders was less evident, the risk of developing AD and AR were both influenced by a combination of fetal growth status and adolescent body mass index (BMI). Compared with those with normal fetal growth and school-aged BMI, the risk of developing AD increased 64% among adolescents with both restricted fetal growth and high BMI (odds ratio 1.64, 95% confidence interval 1.37, 1.97). The risk for this combination was higher than that for either restricted fetal growth or high BMI alone. Nevertheless, the overall interaction between BMI and fetal growth status on atopic disorders did not reach statistical significance.

CONCLUSIONS

Excessive weight gain could be an important risk factor related to developing atopic dermatitis and allergic rhinitis during adolescence, especially among infants born small for gestational age.

Cohort Profile: Swedish Twin Study on Prediction and Prevention of Asthma (STOPPA)

Asthma is a common childhood disease and several risk factors have been identified; however, the impact of genes and environment is not fully understood. The aim of the Swedish Twin study On Prediction and Prevention of Asthma (STOPPA) is to identify environmental (birth characteristics and early life) and genetic (including epigenetic) factors as determinants for asthmatic disease. Based on the Child and Adolescent Twin Study in Sweden (CATSS) (parental interview at 9 or 12 years, N ~23,900) and an asthma and/or wheezing algorithm, we identified a sample of monozygotic (MZ) and dizygotic (DZ) same-sexed twin pairs. The twin pairs were classified as asthma concordant (ACC), asthma discordant (ADC) and healthy concordant (HCC). A sample of 9- to 14-year-old twins and their parents were invited to participate in a clinical examination. Background characteristics were collected in questionnaires and obtained from the National Health Registers. A clinical examination was performed to test lung function and capacity (spirometry with reversibility test and exhaled nitric oxide) and collect blood (serology and DNA), urine (metabolites), feces (microbiota), and saliva (cortisol). In total, 376 twin pairs (752 individual twins) completed the study, response rate 52%. All participating twins answered the questionnaire and >90% participated in lung function testing, blood-, and saliva sampling. This article describes the design, recruitment, data collection, measures, and background characteristics, as well as ongoing and planned analyses in STOPPA. Potential gains of the study include the identification of biomarkers, the emergence of candidates for drug development, and new leads for prevention of asthma and allergic disease.

Exploring the origins of asthma: Lessons from twin studies

This thesis explores the contribution of twin studies, particularly those studies originating from the Danish Twin Registry, to the understanding of the aetiology of asthma. First, it is explored how twin studies have established the contribution of genetic and environmental factors to the variation in the susceptibility to asthma, and to the variation in several aspects of the clinical expression of the disease such as its age at onset, its symptomatology, its intermediate phenotypes, and its relationship with other atopic diseases. Next, it is explored how twin studies have corroborated theories explaining asthma's recent increase in prevalence, and last, how these fit with the explanations of the epidemiological trends in other common chronic diseases of modernity.

Birthweight and the risk of atopic diseases: the ISAAC Phase III study

BACKGROUND

The association between birthweight and asthma, eczema and rhinoconjunctivitisis conflicting.

AIMS

To examine the association between birthweight and symptoms of asthma, eczema and rhinoconjunctivitis.

METHODS

Parents or guardians of children aged 6–7 yr completed written questionnaires about symptoms of asthma, rhinoconjunctivitis and eczema, and several risk factors, including birthweight.

RESULTS

There were 162,324 children from 60 centres in 26 countries. Low birthweight(<2.5 kg) was associated with an increased risk of symptoms of asthma (current wheeze odds ratio = 1.20; 95% confidence interval = 1.12–1.30). Low birthweight was associated with a lower risk of eczema ever. Low birthweight was not associated with rhinoconjunctivitis. Large babies (birthweight ≥4.5 kg) were not associated with any of these outcomes.

CONCLUSIONS

This study has confirmed that low birthweight is a risk factor for symptoms of asthma, but not for rhinoconjunctivitis. The findings for eczema are equivocal.

Placental restriction of fetal growth reduces cutaneous responses to antigen after sensitization in sheep

Prenatal and early childhood exposures are implicated as causes of allergy, but the effects of intrauterine growth restriction on immune function and allergy are poorly defined. We therefore evaluated effects of experimental restriction of fetal growth on immune function and allergic sensitization in adolescent sheep. Immune function (circulating total red and white blood cells, neutrophils, lymphocytes, monocytes, eosinophils, and basophils, and the antibody response to Clostridial vaccination) and responses to house dust mite (HDM) allergen and ovalbumin (OVA) antigen sensitization (specific total Ig, IgG1, and IgE antibodies, and cutaneous hypersensitivity) were investigated in adolescent sheep from placentally restricted (PR, n = 23) and control (n = 40) pregnancies. Increases in circulating HDM-specific IgE (P = 0.007) and OVA-specific IgE (P = 0.038) were greater in PR than control progeny. PR did not alter total Ig, IgG1, or IgM responses to either antigen. PR increased OVA-specific but not HDM-specific IgA responses in females only (P = 0.023). Multiple birth increased Ig responses to OVA in a sex-specific manner. PR decreased the proportion of positive cutaneous hypersensitivity responders to OVA at 24 h (P = 0.030) but had no effect on cutaneous responses to HDM. Acute wheal responses to intradermal histamine correlated positively with birth weight in singletons (P = 0.023). Intrauterine growth restriction may suppress inflammatory responses in skin downstream of IgE induction, without impairment in antibody responses to a nonpolysaccharide vaccine. Discord between cutaneous and IgE responses following sensitization suggests new mechanisms for prenatal allergy programming.

Perinatal factors and the risk of atopic dermatitis: a cohort study

OBJECTIVE

To analyze the effects of pregnancy and early events in the newborn on the risk of subsequent atopic dermatitis (AD) during the first year of life.

PATIENTS AND METHODS

This is a prospective multicenter cohort study of newborns during the first year of life. Newborns identified on random days in three obstetrics departments in the area of Bergamo, Lombardy, Northern Italy, were eligible. At baseline, the mothers were interviewed by medical staff during their stay in hospital after delivery. At 6 and 12 months after delivery, a postal questionnaire was sent to the parents. Relative risks were calculated with and without adjustment by multiple regression analysis.

RESULTS

A total of 1081 newborns entered the study: 796 (74%) parents answered the 12-month questionnaire. Hundred and thirty-eight (17%) reported a diagnosis of AD at 6 months and 222 (28%) at 12 months. Parental history of AD and/or asthma was associated with an increased risk of AD (RR 1.5, 95%CI 1.1-2.0). Birth weight was slightly associated with an increased risk of AD: RR 1.04, 95%CI 1.001-1.08 (continuous variable, increment of 100 grams). No association emerged between breast feeding, smoking, and risk of AD.

CONCLUSIONS

This study in an Italian offspring cohort points to family history of atopic diseases and body weight at birth as relevant risk factors. The study was unable to document associations with other perinatal factors particularly breast feeding and parental smoking in the perinatal period.

Guidelines of care for the management of atopic dermatitis: section 1. Diagnosis and assessment of atopic dermatitis

Atopic dermatitis (AD) is a chronic, pruritic, inflammatory dermatosis that affects up to 25% of children and 2% to 3% of adults. This guideline addresses important clinical questions that arise in the management and care of AD, providing updated and expanded recommendations based on the available evidence. In this first of 4 sections, methods for the diagnosis and monitoring of disease, outcomes measures for assessment, and common clinical associations that affect patients with AD are discussed. Known risk factors for the development of disease are also reviewed.

Apgar score is related to development of atopic dermatitis: cotwin control study

Aim. To study the impact of birth characteristics on the risk of atopic dermatitis in a twin population. Methods. In a population-based questionnaire study of 10,809 twins, 3–9 years of age, from the Danish Twin Registry, we identified 907 twin pairs discordant for parent-reported atopic dermatitis. We cross-linked with data from the Danish National Birth Registry and performed cotwin control analysis in order to test the impact of birth characteristics on the risk of atopic dermatitis. Results. Apgar score, OR (per unit) = 1.23 (1.06–1.44), P = 0.008, and female sex, OR = 1.31 (1.06–1.61), P = 0.012, were risk factors for atopic dermatitis in cotwin control analysis, whereas birth anthropometric factors were not significantly related to disease development. Risk estimates in monozygotic and dizygotic twins were not significantly different for the identified risk factors. Conclusions. In this population-based cotwin control study, high Apgar score was a risk factor for atopic dermatitis. This novel finding must be confirmed in subsequent studies.

Association between maternal characteristics and neonatal birth weight in a Korean population living in the Seoul metropolitan area, Korea: a birth cohort study (COCOA)

Previous studies suggest that maternal characteristics may be associated with neonatal outcomes. However, the influence of maternal characteristics on birth weight (BW) has not been adequately determined in Korean populations. We investigated associations between maternal characteristics and BW in a sample of 813 Korean women living in the Seoul metropolitan area, Korea recruited using data from the prospective hospital-based COhort for Childhood Origin of Asthma and allergic diseases (COCOA) between 2007 and 2011. The mean maternal age at delivery was 32.3 ± 3.5 yr and prepregnancy maternal body mass index (BMI) was 20.7 ± 2.5 kg/m(2). The mean BW of infant was 3,196 ± 406 g. The overall prevalence of a maternal history of allergic disease was 32.9% and the overall prevalence of allergic symptoms was 65.1%. In multivariate regression models, prepregnancy maternal BMI and gestational age at delivery were positively and a maternal history of allergic disease and nulliparity were negatively associated with BW (all P < 0.05). Presence of allergic symptoms in the mother was not associated with BW. In conclusion, prepregnancy maternal BMI, gestational age at delivery, a maternal history of allergic disease, and nulliparity may be associated with BW, respectively.

Fetal growth and risk of childhood asthma and allergic disease

Introduction

Early genetic and environmental factors have been discussed as potential causes for the high prevalence of asthma and allergic disease in the western world, and knowledge on fetal growth and its consequence on future health and disease development is emerging.

Objective

This review article is an attempt to summarize research on fetal growth and risk of asthma and allergic disease. Current knowledge and novel findings will be reviewed and open research questions identified, to give basic scientists, immunologists and clinicians an overview of an emerging research field.

Methods

PubMed-search on pre-defined terms and cross-references.

Results

Several studies have shown a correlation between low birth weight and/or gestational age and asthma and high birth weight and/or gestational age and atopy. The exact mechanism is not yet clear but both environmental and genetic factors seem to contribute to fetal growth. Some of these factors are confounders that can be adjusted for, and twin studies have been very helpful in this context. Suggested mechanisms behind fetal growth are often linked to the feto-maternal circulation, including the development of placenta and umbilical cord. However, the causal link between fetal growth restriction and subsequent asthma and allergic disease remains unexplained. New research regarding the catch-up growth following growth restriction has posited an alternative theory that diseases later on in life result from rapid catch-up growth rather than intrauterine growth restriction per se. Several studies have found a correlation between a rapid weight gain after birth and development of asthma or wheezing in childhood.

Conclusion and clinical relevance

Asthma and allergic disease are multifactorial. Several mechanisms seem to influence their development. Additional studies are needed before we fully understand the causal links between fetal growth and development of asthma and allergic diseases.

The impact of birth mode of delivery on childhood asthma and allergic diseases--a sibling study

BACKGROUND

Caesarean section (CS) has been reported to increase the risk of asthma in offspring. This may be due to that infants delivered by CS are unexposed to vaginal flora, according to the 'hygiene hypothesis'.

OBJECTIVE

Our aim was to investigate if CS increases risk of childhood asthma, and if the risk increase remains after adjustment for familial confounding using sibling design.

METHODS

A register-based cohort study with 87 500 Swedish sibling pairs was undertaken. Asthma outcome variables were collected from national health registers as diagnosis or asthma medication (ICD-10 J45-J46; ATC code R03) during the 10th or 13th year of life (year of follow-up). Mode of delivery and confounders were retrieved from the Medical Birth Register. The data were analysed both as a cohort and with sibling control analysis which adjusts for unmeasured familial confounding.

RESULTS

In the cohort analyses, there was an increased risk of asthma medication and asthma diagnosis during year of follow-up in children born with CS (adjusted ORs, 95% CI 1.13, 1.04-1.24 and 1.10, 1.03-1.18 respectively). When separating between emergency and elective CS the effect on asthma medication remained for emergency CS, but not for elective CS, while both groups had significant effects on asthma diagnosis compared with vaginal delivery. In sibling control analyses, the effect of elective CS on asthma disappeared, while similar but non-significant ORs of medication were obtained for emergency CS.

CONCLUSIONS AND CLINICAL RELEVANCE

An increased risk of asthma medication in the group born by emergency CS, but not elective, suggests that there is no causal effect due to vaginal microflora. A more probable explanation should be sought in the indications for emergency CS.

The Swedish Twin Registry: establishment of a biobank and other recent developments

The Swedish Twin Registry (STR) today contains more than 194,000 twins and more than 75,000 pairs have zygosity determined by an intra-pair similarity algorithm, DNA, or by being of opposite sex. Of these, approximately 20,000, 25,000, and 30,000 pairs are monozygotic, same-sex dizygotic, and opposite-sex dizygotic pairs, respectively. Since its establishment in the late 1950s, the STR has been an important epidemiological resource for the study of genetic and environmental influences on a multitude of traits, behaviors, and diseases. Following large investments in the collection of biological specimens in the past 10 years we have now established a Swedish twin biobank with DNA from 45,000 twins and blood serum from 15,000 twins, which effectively has also transformed the registry into a powerful resource for molecular studies. We here describe the main projects within which the new collections of both biological samples as well as phenotypic measures have been collected. Coverage by year of birth, zygosity determination, ethnic heterogeneity, and influences of in vitro fertilization are also described.

Gestational age at birth and risk of allergic rhinitis in young adulthood

BACKGROUND

Previous studies of the association between gestational age or birth weight and allergic rhinitis in later life have had various limitations, including the inability to estimate risk among subjects born extremely preterm or to examine specific contributions of gestational age and fetal growth.

OBJECTIVE

We sought to determine whether gestational age at birth independent of fetal growth is associated with allergic rhinitis medication prescription in a national cohort of young adults.

METHODS

We conducted a national cohort study of 630,090 infants born in Sweden from 1973 through 1979 including 27,953 born preterm (<37 weeks) and followed for prescription of nasal corticosteroids and oral antihistamines in 2005-2009 (age, 25.5-37.0 years). Medication data were obtained from all outpatient and inpatient pharmacies throughout Sweden.

RESULTS

The overall prevalence of nasal corticosteroid and oral antihistamine prescription was 16.3% and 16.8%, respectively, which is similar to the reported prevalence of allergic rhinitis in this population. Low gestational age at birth was associated with a decreased risk of nasal corticosteroid and oral antihistamine prescription in young adulthood after adjusting for fetal growth and other potential confounders. For subjects born extremely preterm (23-28 weeks), adjusted odds ratios were 0.70 (95% CI, 0.51-0.96) for nasal corticosteroid prescription and 0.45 (95% CI, 0.27-0.76) for both nasal corticosteroid and oral antihistamine prescription relative to those born at full term.

CONCLUSION

These findings suggest that low gestational age at birth independent of fetal growth is associated with a decreased risk of allergic rhinitis in young adulthood, possibly because of a protective effect of earlier exposure to pathogens.

[What's new in paediatric dermatology?]

This paper summarizes a review of the medical literature focused on the field of pediatric dermatology from December 2009 to November 2010. Our objective was to select the papers published in the main journals of dermatology, internal medicine, pediatrics, infectious diseases and allergy that bring new information and significant advances concerning skin diseases in children. Recent advances in the field of infantile hemangiomas and atopic dermatitis are particularly detailed. This review also covers the main the following topics: psoriasis, Kawasaki disease, head lice and warts management, lichen, rare diseases such as epidermolyses bullosae.