Association of sleep quality, media use and book reading with behavioral problems in early childhood. The Ulm SPATZ Health Study

Study Objectives

The objective of the study was to investigate the association of sleep quality, media use and book reading on internalizing, externalizing and prosocial behavior in early childhood.

Methods

In this cross-sectional study, we investigated a data set consisting of three consecutive yearly waves of the prospective Ulm SPATZ Health Study, conducted in southern Germany with 565, 496, and 421 children of 4-6 years of age, respectively.Standardized effects of the overall score and subscales of the Children's Sleep Habits Questionnaire, parent-reported child media use and book reading as well as their interaction term on the total score of the Strengths and Difficulties Questionnaire along with its externalizing, internalizing and prosocial subscales were estimated by multivariate adjusted random intercept mixed models.

Results

Overall sleep quality was associated more with internalizing than externalizing behavior; parasomnias associated with both behaviors. Night waking and sleep anxiety associated only with internalizing behavior. High levels of media use were associated with less internalizing behavior. More book reading resulted in less externalizing and internalizing behavior but more prosocial behavior. Finally, book reading and media use do not interact to determine child's behavior.

Conclusions

The current work supports a strategy of monitoring sleep quality, reducing media use and promoting book reading in order to avoid behavioral problems in early childhood.

Psychosocial stress and longitudinally measured gestational weight gain throughout pregnancy: The Ulm SPATZ Health Study

Psychosocial stress is thought to influence gestational weight gain (GWG), but results are inconsistent. We investigated the relationship of questionnaire-based maternal stress and related constructs assessed at childbirth with maternal weight measured throughout pregnancy. Data were derived from the Ulm SPATZ Health Study, a birth cohort recruited from the general population (04/2012-05/2013, Ulm, Germany). Adjusted generalized estimating equations were performed. Regression coefficients (b) and 95% confidence intervals, each highest versus lowest tertile of stress or related constructs, are presented. In 748 women, we observed positive associations for maternal chronic stress (b = 4.36 kg (1.77; 6.95)), depressive symptoms (b = 2.50 kg (0.14; 4.86)), anxiety symptoms (b = 3.26 kg (0.62, 5.89)), and hair cortisol (b = 3.35 kg (0.86; 5.83)) with maternal weight at the first gestational month. GWG was considerably lower in mothers with higher chronic stress. Pregnancy-related anxiety was positively related to weight at first month (b = 4.16 kg (1.74; 6.58)) and overall GWG. In contrast, no association was observed between anxiety symptoms and GWG. Odds ratios for association with inadequate weight gain according to Institute of Medicine recommended cutoffs differed from the results presented obove. There is evidence of an association between stress and weight gain lying beyond the recommended cut-offs, which however needs further corroboration.

The association of potential stressors with hair steroids in parents with small children: The Ulm SPATZ health study

Previous studies have reported weak associations between questionnaire-based stress measurements and hair steroids. A stronger relationship may exist in highly stressed subpopulations or with stress brought up by novel or unpredictable situations. In the Ulm SPATZ Health Study, conducted in Ulm, Germany, baseline recruitment 04/2012 to 05/2013, we analyzed data of families enrolled shortly after childbirth. Mothers completed standardized questionnaires assessing sociodemographic, health- and family-life-related factors, and the Screening Scale of the Trier Inventory of Chronic Stress (TICS) at 6 months (T2) and 12 months postpartum (T3). Their current partners completed SSCS-TICS and an Effort-Reward Imbalance (ERI) Questionnaire obtained at 6 weeks postpartum (T1). Partners (n = 375 at T1) and mothers (n = 654 at T2 or T3) provided a 2 to 3-cm hair segment for hair analysis. Adjusted linear and cubic spline regressions were used to analyze (non-)linear relationships between potential stressors and hair cortisol (hairF) and hair cortisone (hairE) concentrations as well as the respective change scores between 12 months and 6 months. Lacking social recognition and high paternal work overload were significantly associated with paternal hairF in cubic spline models (test for overall association, chi² = 8.24, p = 0.041, chi² = 8.41, p = 0.038) but not in linear models. However, the association between ERI and hairF (chi² = 7.54, p = 0.059) was marginally significant. Maternal education was related to maternal hairF and hairE at T2. No association was observed between maternal postpartum employment and hair steroids at T2 or T3. Conversely, we could show a relationship between some change scores of stress and hairE in mothers. Considering non-linearity and family-related stressors, there are few associations between questionnaire-based stress measurements and hairF or hairE. Novelty of stressors was not shown to be a relevant factor.

High levels of butyrate and propionate in early life are associated with protection against atopy

BACKGROUND

Dietary changes are suggested to play a role in the increasing prevalence of allergic diseases and asthma. Short-chain fatty acids (SCFAs) are metabolites present in certain foods and are produced by microbes in the gut following fermentation of fibers. SCFAs have been shown to have anti-inflammatory properties in animal models. Our objective was to investigate the potential role of SCFAs in the prevention of allergy and asthma.

METHODS

We analyzed SCFA levels by high-performance liquid chromatography (HPLC) in fecal samples from 301 one-year-old children from a birth cohort and examined their association with early life exposures, especially diet, and allergy and asthma later in life. Data on exposures and allergic diseases were collected by questionnaires. In addition, we treated mice with SCFAs to examine their effect on allergic airway inflammation.

RESULTS

Significant associations between the levels of SCFAs and the infant's diet were identified. Children with the highest levels of butyrate and propionate (≥95th percentile) in feces at the age of one year had significantly less atopic sensitization and were less likely to have asthma between 3 and 6 years. Children with the highest levels of butyrate were also less likely to have a reported diagnosis of food allergy or allergic rhinitis. Oral administration of SCFAs to mice significantly reduced the severity of allergic airway inflammation.

CONCLUSION

Our results suggest that strategies to increase SCFA levels could be a new dietary preventive option for allergic diseases in children.

An approach to the asthma-protective farm effect by geocoding: Good farms and better farms

BACKGROUND

The highly consistent association of growing up on a farm with a reduced asthma risk has so far been attributed to direct farm exposure. In contrast, geographic determinants of the larger environment have never been assessed. In this study, the effects of proximity to farms and environmental variables in relation to the residential address on asthma and atopy were assessed.

METHODS

Addresses of 2265 children of the Bavarian arm of the GABRIELA study were converted into geocodes. Proximity to the nearest cow farm was calculated, and environmental characteristics were derived from satellite data or terrestrial monitoring. Bacterial diversity in mattress dust samples was assessed in 501 children by sequencing of the 16S rRNA amplicons. Logistic regression models were used to calculate associations between outcomes and exposure variables.

RESULTS

Asthma and atopy were inversely associated with the presence of a farm within a radius of maximum 100 m. The environmental variables greenness, tree cover, soil sealing, altitude, air pollution differed not only between farm and non-farm children but also between farm children with and without another farm nearby. The latter distinction revealed strong associations with characteristics of traditional farms including a broader diversity of microbial exposure, which mainly contributed to the protective effect on asthma. In non-farm children, the protective effect of a farm nearby was completely explained by consumption of farm milk.

CONCLUSIONS

Clustering of farms within a neighborhood of 100 m is strongly associated with the protective effect on asthma and may represent a more traditional style of farming with broader microbial exposure.

Pregnancy and perinatal conditions and atopic disease prevalence in childhood and adulthood

BACKGROUND

Previous studies showed controversial results for the influence of pregnancy-related and perinatal factors on subsequent respiratory and atopic diseases in children. The aim of this study was to assess the association between perinatal variables and the prevalence of asthma, bronchial hyperreactivity (BHR), flexural eczema (FE), allergic rhinitis, and sensitization in childhood and early adulthood.

METHODS

The studied population was first examined in Munich and Dresden in 1995/1996 at age 9-11 years. Participants were followed until age 19-24 years using questionnaires and clinical examinations. Associations between perinatal data and subsequent atopic diseases were examined using logistic regression analyses adjusting for potential confounders.

RESULTS

Cesarean section was statistically significantly associated with BHR in early adulthood (odds ratio 4.8 [95% confidence interval 1.5-15.2]), while assisted birth was associated with presence of asthma symptoms in childhood (2.2 [1.2-3.9]), FE symptoms (2.2 [1.2-4.3]) and doctor's diagnosis of atopic dermatitis (1.9 [1.0-3.4]) in childhood, and sensitization in early adulthood (2.2 [1.1-4.3]). Lower birth length (1.9 [1.1-3.2]), lower birthweight (0.5 [0.3-0.9]), and higher birthweight (0.6 [0.4-1.0]) were predictive of sensitization in early adulthood compared to average birth length and birthweight, respectively. None of the other perinatal factors showed statistically significant associations with the outcomes.

CONCLUSIONS

Our results indicate that children who are born by cesarean section and especially by assisted birth, might be at greater risk for developing asthma, FE, and sensitization and should hence be monitored. Prenatal maternal stress might partly explain these associations, which should be further investigated.

New approach shows no association between maternal milk fatty acid composition and childhood wheeze or asthma

BACKGROUND

Previous observational studies have implied breastmilk fatty acid composition may play a role in the development of atopic eczema or atopic sensitization in breastfed infants and toddlers. However, studies investigating associations with wheeze and asthma in later childhood are scarce and did not account for inherent correlation of compositional data. Our aim was to explore the association of maternal milk fatty acid composition with childhood wheezing phenotypes and asthma up to age 13 years using a new statistical approach.

METHODS

Breastmilk was collected 6 weeks and 6 months postdelivery in the Ulm Birth Cohort Study (n=720 and n=454, respectively). Concentrations of 28 fatty acids were measured by high-resolution capillary gas-liquid chromatography. To control for constant-sum constraint, concentration data were transformed using the centered log ratio method. Compositional biplots and correlation matrices were used to group centered log ratio transformed fatty acids. Adjusted risk ratios with parent-reported wheezing phenotypes and doctor-diagnosed asthma were computed using a modified Poisson regression.

RESULTS

We observed no straightforward evidence of associations between overall breastmilk fatty acid composition and specific wheeze phenotypes or doctor-diagnosed asthma.

CONCLUSION

Using appropriate statistical methodology, we report null associations. These findings may partly be attributable to several cohort-specific factors associated with breastfeeding and breastmilk collection. Further studies could improve on ours by analyzing samples of breastmilk and formula and by including all children for whom these are exclusively or together the major source of fatty acids in the first months of life.

Overview of systematic reviews in allergy epidemiology

BACKGROUND

There is a substantial body of evidence on the epidemiology of allergic conditions, which has advanced the understanding of these conditions. We aimed to systematically identify systematic reviews and meta-analyses on the epidemiology of allergic diseases to assess what has been studied comprehensively and what areas might benefit from further research.

METHODS

We searched PubMed and EMBASE up to 12/2014 for systematic reviews on epidemiological research on allergic diseases. We indexed diseases and topics covered and extracted data on the search characteristics of each systematic review.

RESULTS

The search resulted in 3991 entries after removing duplicates, plus 20 other items found via references and conference abstracts; 421 systematic reviews were relevant and included in this overview. The majority contained some evidence on asthma (72.9%). Allergic rhinitis, atopic eczema and food hypersensitivity were covered in 15.7%, 24.5% and 9.0%, respectively. Commonly studied risk factors for atopic eczema included dietary and microbial factors, while for asthma, pollution and genetic factors were often investigated in systematic reviews. There was some indication of differing search characteristics across topics.

CONCLUSION

We present a comprehensive overview with an indexed database of published systematic reviews in allergy epidemiology. We believe that this clarifies where most research interest has focussed and which areas could benefit from further research. We propose that this effort is updated every few years to include the most recently published evidence and to extend the search to an even broader list of hypersensitivity/allergic disorders.

A switch in regulatory T cells through farm exposure during immune maturation in childhood

BACKGROUND

Farm exposure protects against development of allergies early in life. At 4.5 years, protection against asthma by farm-milk exposure was partially mediated by regulatory T cells (Tregs). The aim of this study was to investigate the critical time window of the 'asthma-protective' farm effect via Tregs during childhood immune maturation.

METHODS

Tregs were assessed longitudinally at 4.5 and 6 years in 111 children (56 farm and 55 reference children) from the PASTURE/EFRAIM birth cohort (flow cytometry). Peripheral blood mononuclear cells were cultured unstimulated (U), with phorbol 12-myristate 13-acetate/ionomycin (PI) or lipopolysaccharide (LPS), and stained for Tregs (CD4⁺ CD25^high FOXP3^upper20% ). mRNA expression of Treg/Th1/Th2/Th17-associated cell markers was measured ex vivo. Suppressive capacity of Tregs on effector cells and cytokines was assessed. Detailed questionnaires assessing farm exposures and clinical phenotypes from birth until age 6 years were answered by the parents.

RESULTS

Treg percentage before and after stimulation and FOXP3mRNA expression ex vivo decreased from age 4.5 to 6 years (P(U,LPS) < 0.001; P(PI) = 0.051; P(FOXP3) < 0.001). High vs low farm-milk and animal-stable exposure was associated with decreased LPS-stimulated Treg percentage at age 6 years (P(LPS) = 0.045). Elevated LPS-stimulated-Treg percentage at age 6 was associated with increased risk of asthma (aOR = 11.29, CI: 0.96-132.28, P = 0.053). Tregs from asthmatics vs nonasthmatics suppressed IFN-γ (P = 0.015) and IL-9 (P = 0.023) less efficiently. mRNA expression of Th1/Th2/Th17-associated cell markers decreased between 4.5 and 6 years (P < 0.001).

CONCLUSIONS

Tregs at the age of 6 years were decreased with farm exposure and increased within asthmatics, opposite to age 4.5 years. This immunological switch defines a critical 'time window' for Treg-mediated asthma protection via environmental exposure before age 6 years.

Environmental and mucosal microbiota and their role in childhood asthma

BACKGROUND

High microbial diversity in the environment has been associated with lower asthma risk, particularly in children exposed to farming. It remains unclear whether this effect operates through an altered microbiome of the mucosal surfaces of the airways.

METHODS

DNA from mattress dust and nasal samples of 86 school age children was analyzed by 454 pyrosequencing of the 16S rRNA gene fragments. Based on operational taxonomic units (OTUs), bacterial diversity and composition were related to farm exposure and asthma status.

RESULTS

Farm exposure was positively associated with bacterial diversity in mattress dust samples as determined by richness (P = 8.1 × 10^-6 ) and Shannon index (P = 1.3 × 10^-5 ). Despite considerable agreement of richness between mattress and nasal samples, the association of richness with farming in nasal samples was restricted to a high gradient of farm exposure, that is, exposure to cows and straw vs no exposure at all. In mattress dust, the genera Clostridium, Facklamia, an unclassified genus within the family of Ruminococcaceae, and six OTUs were positively associated with farming. Asthma was inversely associated with richness [aOR = 0.48 (0.22-1.02)] and Shannon index [aOR = 0.41 (0.21-0.83)] in mattress dust and to a lower extent in nasal samples [richness aOR 0.63 = (0.38-1.06), Shannon index aOR = 0.66 (0.39-1.12)].

CONCLUSION

The stronger inverse association of asthma with bacterial diversity in mattress dust as compared to nasal samples suggests microbial involvement beyond mere colonization of the upper airways. Whether inhalation of metabolites of environmental bacteria contributes to this phenomenon should be the focus of future research.

Moisture damage in home associates with systemic inflammation in children

This study investigated the association between confirmed moisture damage in homes and systemic subclinical inflammation in children. Home inspections were performed in homes of 291 children at the age of 6 years. Subclinical inflammation at the age of 6 years was assessed by measuring the circulating levels of C-reactive protein (CRP) and leukocytes in peripheral blood and fractional exhaled nitric oxide (FeNO). Proinflammatory cytokines interleukin (IL)-1β and IL-6 and tumor necrosis factor (TNF)-α were measured in unstimulated, and in phorbol 12-myristate 13-acetate and ionomycin (PI), lipopolysaccharide (LPS), or peptidoglycan (PPG)-stimulated whole blood. Major moisture damage in the child's main living areas (living room, kitchen, or child's bedroom) and moisture damage with mold in the bathroom were associated with increased levels of CRP and stimulated production of several proinflammatory cytokines. There were no significant associations between moisture damage/visible mold and leukocyte or FeNO values. The results suggest that moisture damage or mold in home may be associated with increased systemic subclinical inflammation and proinflammatory cytokine responsiveness.

High level of fecal calprotectin at age 2 months as a marker of intestinal inflammation predicts atopic dermatitis and asthma by age 6

BACKGROUND

Gut microbiota and intestinal inflammation regulate the development of immune-mediated diseases, such as allergies. Fecal calprotectin is a biomarker of intestinal inflammation.

OBJECTIVE

We evaluated the association of early-age fecal calprotectin levels to the later development of allergic diseases in children from farming and non-farming environments and further studied the effect of gut microbiota on the fecal calprotectin levels.

METHODS

Fecal calprotectin was measured from 758 infants participating in the PASTURE study at the age of 2 months using the ELISA method. Serum-specific IgE levels were measured at 6 years of age. Data of environmental factors, doctor-diagnosed atopic dermatitis (AD) and asthma were collected by questionnaire. Multivariate logistic regression models were used for analysis. The composition of fecal microbiota was analysed in a subgroup of 120 infants with 16S rRNA pyrosequencing. The effect of Escherichia coli lipopolysaccharide (LPS) on in vitro monocyte IL-10 secretion was studied by flow cytometry.

RESULTS

The infants with high fecal calprotectin levels at 2 months, that is above the 90th percentile, had an increased risk of developing AD and asthma/asthmatic bronchitis by the age of 6 years (aOR 2.02 (1.06-3.85) and 2.41 (1.25-4.64), respectively). High fecal calprotectin levels correlated negatively with fecal Escherichia. LPS from E. coli stimulated production of IL-10 in monocytes.

CONCLUSION AND CLINICAL RELEVANCE

High degree intestinal inflammation at 2 months of age, detected as high fecal calprotectin, predicted asthma and AD by the age of 6 years and was linked to low abundance of fecal Escherichia. Impaired IL-10 activation due to the lack of colonization with E. coli could explain the intestinal inflammation associated high fecal calprotectin and later risk of asthma and AD. Our results have implications for the design of probiotic treatments and suggest that early intestinal colonization has long-term health effects.

Childhood asthma is associated with mutations and gene expression differences of ORMDL genes that can interact

BACKGROUND

Genomewide association studies identified ORMDL3 as a plausible asthma candidate gene. ORMDL proteins regulate sphingolipid metabolism and ceramide homeostasis and participate in lymphocyte activation and eosinophil recruitment. Strong sequence homology between the three ORMDL genes and ORMDL protein conservation among different species suggest that they may have shared functions. We hypothesized that if single nucleotide polymorphisms (SNPs) in ORMDL3 alter its gene expression and play a role in asthma, variants in ORMDL1 and ORMDL2 might also be associated with asthma.

METHODS

Asthma associations of 44 genotyped SNPs were determined in at least 1303 subjects (651 asthmatics). ORMDL expression was evaluated in peripheral blood mononuclear cells (PBMC) from 55 subjects (eight asthmatics) before and after allergen stimulation, and in blood (n = 60, 5 asthmatics). Allele-specific cis-effects on ORMDL expression were assessed. Interactions between human ORMDL proteins were determined in living cells.

RESULTS

Sixteen SNPs in all three ORMDLs were associated with asthma (14 in ORMDL3). Baseline expression of ORMDL1 (P = 1.7 × 10(-6) ) and ORMDL2 (P = 4.9 × 10(-5) ) was significantly higher in PBMC from asthmatics, while induction of ORMDLs upon stimulation was stronger in nonasthmatics. Disease-associated alleles (rs8079416, rs4795405, rs3902920) alter ORMDL3 expression. ORMDL proteins formed homo- and heterooligomers and displayed similar patterns of interaction with SERCA2 and SPT1.

CONCLUSIONS

Polymorphisms in ORMDL genes are associated with asthma. Asthmatics exhibit increased ORMDL levels, suggesting that ORMDLs contribute to asthma. Formation of heterooligomers and similar interaction patterns with proteins involved in calcium homeostasis and sphingolipid metabolism could indicate shared biological roles of ORMDLs, influencing airway remodeling and hyperresponsiveness.

A polymorphism in the TH 2 locus control region is associated with changes in DNA methylation and gene expression

BACKGROUND

Genomewide association and epigenetic studies found a region within the RAD50 gene on chromosome 5q31 to be associated with total serum IgE levels and asthma. In mice, this region harbors a locus control region for nearby TH 2 cytokines, which is characterized by four Rad50 DNase I hypersensitive sites (RHS4-7). Among these, RHS7 seems to have the strongest impact on TH 2 differentiation. We investigated whether within the human homolog of RHS7, functional polymorphisms exist, which could affect DNA methylation or gene expression in the 5q31 locus and might have an influence on asthma status or IgE regulation.

METHODS

The human RHS7 region was fine mapped using 1000 genomes database information. In silico analysis and electrophoretic mobility shift assays were used to assess SNP function. Allele-specific effects on DNA methylation were evaluated in cord blood (n = 73) and at age of 4.5 years (n = 61) by pyrosequencing. Allele-specific effects on RAD50, IL4, and IL13 expression were analyzed in 100 subjects. Associations with asthma and IgE levels were investigated in the MAGICS/ISAAC II population (n = 1145).

RESULTS

Polymorphism rs2240032 in the RHS7 region is suggestive of allele-specific transcription factor binding, affects methylation of the IL13 promoter region and influences RAD50 and IL4 expression (lowest P = 0.0027). It is also associated with total serum IgE levels (P = 0.0227).

CONCLUSION

A functional relevant polymorphism in the TH 2 locus control region, equivalent to RHS7 in mice, affects DNA methylation and gene expression within 5q31 and influences total serum IgE on the population level.

Soluble immunoglobulin A in breast milk is inversely associated with atopic dermatitis at early age: the PASTURE cohort study

BACKGROUND

The role of breastfeeding for the development of atopic diseases in childhood is contradictory. This might be due to differences in the composition of breast milk and levels of antimicrobial and anti-inflammatory components.

OBJECTIVE

The objective of this study was to examine whether levels of total immunoglobulin A (IgA) or transforming growth factor-β1 (TGF-β1) in breast milk were associated with the risk of developing atopic dermatitis (AD), atopic sensitization or asthma at early age taking breastfeeding duration into account.

METHODS

The birth cohort study PASTURE conducted in Finland, France, Germany and Switzerland provided 610 breast milk samples collected 2 months after delivery in which soluble IgA (sIgA) and TGF-β1 levels were measured by ELISA. Duration of breastfeeding was assessed using weekly food frequency diaries from month 3 to month 12. Data on environmental factors, AD and asthma were collected by questionnaires from pregnancy up to age 6. Atopic status was defined by specific IgE levels in blood collected at the ages of 4 and 6 years. Multivariate logistic regression models were used for statistical analysis.

RESULTS

Soluble IgA and TGF-β1 levels in breast milk differed between countries, and sIgA levels were associated with environmental factors related to microbial load, for example, contact to farm animals or cats during pregnancy, but not with raw milk consumption. sIgA levels were inversely associated with AD up to the of age 2 years (P-value for adjusted linear trend: 0.005), independent of breastfeeding duration. The dose of sIgA ingested in the first year of life was associated with reduced risk of AD up to the age of 2 (aOR, 95% CI: 0.74; 0.55-0.99) and 4 years (0.73; 0.55-0.96). No clear associations between sIgA and atopy or asthma up to age 6 were observed. TGF-β1 showed no consistent association with any investigated health outcome.

CONCLUSION AND CLINICAL RELEVANCE

IgA in breast milk might protect against the development of AD.

Fine-mapping of IgE-associated loci 1q23, 5q31, and 12q13 using 1000 Genomes Project data

BACKGROUND

Genome-wide association studies (GWAS) repeatedly identified 1q23 (FCER1A), 5q31 (RAD50-IL13 and IL4), and 12q13 (STAT6) as major susceptibility loci influencing the regulation of total serum IgE levels. As GWAS may be insufficient to capture causal variants, we performed fine-mapping and re-genotyping of the three loci using 1000 Genomes Project datasets.

METHODS

Linkage disequilibrium tagging polymorphisms and polymorphisms of putative functional relevance were genotyped by chip technology (24 polymorphisms) or MALDI-TOF-MS (40 polymorphisms) in at least 1303 German children (651 asthmatics). The effect of polymorphisms on total serum IgE, IgE percentiles, and atopic diseases was assessed, and a risk score model was applied for gene-by-gene interaction analyses. Functional effects of putative causal variants from these three loci were studied in silico.

RESULTS

Associations from GWAS were confirmed and extended. For 1q23 and 5q31, the majority of associations were found with mild to moderately elevated IgE levels, while in the 12q13 locus, single-nucleotide polymorphisms (SNPs) were associated with strongly elevated IgE levels. Gene-by-gene interaction analyses suggested that the presence of mutations in all three loci increases the risk for elevated IgE up to fourfold.

CONCLUSION

This fine-mapping study confirmed previous associations and identified novel associations of SNPs in 1q23, 5q31, and 12q13 with different levels of serum IgE and their concomitant contribution to IgE regulation.

Quantity and diversity of environmental microbial exposure and development of asthma: a birth cohort study

Background

Early-life exposure to environmental microbial agents may be associated with the development of allergies. The aim of the study was to identify better ways to characterize microbial exposure as a predictor of respiratory symptoms and allergies.

Methods

A birth cohort of 410 children was followed up until 6 years of age. Bacterial endotoxin, 3-hydroxy fatty acids, N-acetyl-muramic acid, fungal extracellular polysaccharides (EPS) from Penicillium and Aspergillus spp., β-D-glucan, ergosterol, and bacterial or fungal quantitative polymerase chain reactions (qPCRs) were analyzed from dust samples collected at 2 months of age. Asthma, wheezing, cough, and atopic dermatitis were assessed using repeated questionnaires. Specific IgEs were determined at the age of 1 and 6 years.

Results

Only few associations were found between single microbial markers and the studied outcomes. In contrast, a score for the total quantity of microbial exposure, that is, sum of indicators for fungi (ergosterol), Gram-positive (muramic acid) bacteria, and Gram-negative (endotoxin) bacteria, was significantly (inverted-U shape) associated with asthma incidence (P < 0.001): the highest risk was found at medium levels (adjusted odds ratio (aOR) 2.24, 95% confidence interval (95% CI) 0.87–5.75 for 3rd quintile) and the lowest risk at the highest level (aOR 0.34, 95% CI 0.09–1.36 for 5th quintile). The microbial diversity score, that is, sum of detected qPCRs, was inversely associated with risk of wheezing and was significantly (inverted-U shape) associated with sensitization to inhalant allergens.

Conclusion

Score for quantity of microbial exposure predicted asthma better than single microbial markers independently of microbial diversity and amount of dust. Better indicators of total quantity and diversity of microbial exposure are needed in studies on the development of asthma.

Polymorphisms in the IRF-4 gene, asthma and recurrent bronchitis in children

BACKGROUND

Interferon-regulatory factors (IRFs) play a crucial role in immunity, not only influencing interferon expression but also T cell differentiation. IRF-4 was only recently recognized as a further major player in T cell differentiation.

OBJECTIVE

As IRF-1 polymorphisms were shown to be associated with atopy and allergy, we comprehensively investigated effects of IRF-4 variants on allergy, asthma and related phenotypes in German children.

METHODS

Fifteen tagging single nucleotide polymorphisms (SNPs) in the IRF-4 gene were genotyped by MALDI-TOF MS in the cross-sectional ISAAC phase II study population from Munich and Dresden (age 9-11; N = 3099). Replication was performed in our previously established genome-wide association study (GWAS) data set (N = 1303) consisting of asthma cases from the Multicenter Asthma Genetic in Childhood (MAGIC) study and reference children from the ISAAC II study.

RESULTS

SNPs were not significantly associated with asthma but with bronchial hyperresponsiveness, atopy and, most interestingly, with recurrent bronchitis in the first data set. The IRF-4 variant rs9378805 was associated with recurrent bronchitis in the ISAAC population and replicated in the GWAS data set where further SNPs showed associations with recurrent bronchitis and asthma.

CONCLUSIONS

We found genetic associations in IRF-4 to be associated with recurrent bronchitis in our two study populations. Associated polymorphisms are localized in a putative regulatory element in the 3'UTR region of IRF-4. These findings suggest a putative role of IRF-4 in the development of bronchitis.

A role of FCER1A and FCER2 polymorphisms in IgE regulation

BACKGROUND

Both FCER2 and FCER1A encode subunits of IgE receptors. Variants in FCER1A were previously identified as major determinants of IgE levels in genome-wide association studies.

METHODS

Here we investigated in detail whether FCER2 polymorphisms affect IgE levels alone and/or by interaction with FCER1A polymorphisms. To cover the genetic information of FCER2, 21 single-nucleotide polymorphisms (SNPs) were genotyped by Illumina HumanHap300 BeadChip (5 SNPs) and the matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS; 14 SNPs) in at least 1303 Caucasian children (651 asthmatics) (ISAAC II/ MAGICS population); genotypes of two SNPs were imputed.

RESULTS

SNP rs3760687 showed the most consistent effect on total serum IgE levels (b [SE] = -0.38 [0.16]; P = 0.016), while FCER2 polymorphisms in general were predominantly associated with mildly-to-moderately increased IgE levels (50th and 66th percentiles). Gene-by-gene interaction analysis suggests that FCER2 polymorphism rs3760687 influences IgE levels mainly in individuals not homozygous for the risk allele of FCER1A polymorphism rs2427837, which belongs to the major IgE-determining tagging bin in the population.

CONCLUSION

FCER2 polymorphism rs3760687 affects moderately elevated total serum IgE levels, especially in the absence of homozygosity for the risk allele of FCER1A SNP rs2427837.

Dampness and moulds in relation to respiratory and allergic symptoms in children: results from Phase Two of the International Study of Asthma and Allergies in Childhood (ISAAC Phase Two)

BACKGROUND

Many studies report that damp housing conditions are associated with respiratory symptoms. Less is known about mechanisms and possible effect modifiers. Studies of dampness in relation to allergic sensitization and eczema are scarce.

OBJECTIVE

We study the influence of damp housing conditions world-wide on symptoms and objective outcomes.

METHODS

Cross-sectional studies of 8-12-year-old children in 20 countries used standardized methodology from Phase Two of the International Study of Asthma and Allergies in Childhood (ISAAC). Symptoms of asthma, rhinitis and eczema, plus residential exposure to dampness and moulds, were ascertained by parental questionnaires (n = 46 051). Skin examination, skin prick tests (n = 26 967) and hypertonic saline bronchial challenge (n = 5713) were performed. In subsamples stratified by wheeze (n = 1175), dust was sampled and analysed for house dust mite (HDM) allergens and endotoxin.

RESULTS

Current exposure to dampness was more common for wheezy children (pooled odds ratio 1.58, 95% CI 1.40-1.79) and was associated with greater symptom severity among wheezers, irrespective of atopy. A significant (P < 0.01) adverse effect of dampness was also seen for cough and phlegm, rhinitis and reported eczema, but not for examined eczema, nor bronchial hyperresponsiveness. HDM sensitization was more common in damp homes (OR 1.16, 1.03-1.32). HDM-allergen levels were higher in damp homes and were positively associated with HDM-sensitization, but not wheeze.

CONCLUSION

A consistent association of dampness with respiratory and other symptoms was found in both affluent and non-affluent countries, among both atopic and non-atopic children. HDM exposure and sensitization may contribute, but the link seems to be related principally to non-atopic mechanisms.

Serum vitamin E concentrations at 1 year and risk of atopy, atopic dermatitis, wheezing, and asthma in childhood: the PASTURE study

BACKGROUND

Prospective studies investigating the role of serum vitamin E concentrations during early life in the development of childhood allergies and asthma are limited.

OBJECTIVE

To study the associations between serum vitamin E concentrations at first year of life and longitudinal development of atopy, atopic dermatitis, wheeze, and asthma up to 6 years of age.

METHODS

The setting was the PASTURE study, a multicenter prospective birth cohort study in five European rural settings. Children of 1133 mothers recruited during pregnancy were followed from birth with measurement of serum vitamin E levels at year 1 and repeated assessments of serum immunoglobulin E antibodies (year 1, 4.5, 6), atopic dermatitis, wheezing symptoms, and asthma (year 1, 1.5, 2, 3, 4, 5, 6).

RESULTS

At 6 years of age, 66% and 82% of the original 1133 subjects underwent blood test for IgE and answered the questionnaire, respectively. We did not observe any statistically significant associations between serum vitamin E concentrations at year 1 and the endpoints, but borderline inverse associations between alpha tocopherol and wheezing without cold (OR 0.45, 95% CI 0.19-1.09) and any wheezing symptom (OR 0.52, 95% CI 0.27-1.02).

CONCLUSIONS

Serum vitamin E concentrations at year 1 were not associated with allergies or asthma by 6 years of age. While further prospective studies with repeated assessments of vitamin E during early life may clarify its putative role in the development of the diseases, it is also possible that the antioxidant hypothesis in the development of allergies and asthma does not hold.

Genome-wide association study of body mass index in 23 000 individuals with and without asthma

BACKGROUND

Both asthma and obesity are complex disorders that are influenced by environmental and genetic factors. Shared genetic factors between asthma and obesity have been proposed to partly explain epidemiological findings of co-morbidity between these conditions.

OBJECTIVE

To identify genetic variants that are associated with body mass index (BMI) in asthmatic children and adults, and to evaluate if there are differences between the genetics of BMI in asthmatics and healthy individuals.

METHODS

In total, 19 studies contributed with genome-wide analysis study (GWAS) data from more than 23 000 individuals with predominantly European descent, of whom 8165 are asthmatics.

RESULTS

We report associations between several DENND1B variants (P = 2.2 × 10(-7) for rs4915551) on chromosome 1q31 and BMI from a meta-analysis of GWAS data using 2691 asthmatic children (screening data). The top DENND1B single nucleotide polymorphisms(SNPs) were next evaluated in seven independent replication data sets comprising 2014 asthmatics, and rs4915551 was nominally replicated (P < 0.05) in two of the seven studies and of borderline significance in one (P = 0.059). However, strong evidence of effect heterogeneity was observed and overall, the association between rs4915551 and BMI was not significant in the total replication data set, P = 0.71. Using a random effects model, BMI was overall estimated to increase by 0.30 kg/m(2) (P = 0.01 for combined screening and replication data sets, N = 4705) per additional G allele of this DENND1BSNP. FTO was confirmed as an important gene for adult and childhood BMI regardless of asthma status.

CONCLUSIONS AND CLINICAL RELEVANCE

DENND1B was recently identified as an asthma susceptibility gene in a GWAS on children, and here, we find evidence that DENND1B variants may also be associated with BMI in asthmatic children. However, the association was overall not replicated in the independent data sets and the heterogeneous effect of DENND1B points to complex associations with the studied diseases that deserve further study.

Asthma and allergies: is the farming environment (still) protective in Poland? The GABRIEL Advanced Studies

BACKGROUND

Evidence exists that a farming environment in childhood may provide protection against atopic respiratory disease. In the GABRIEL project based in Poland and Alpine regions of Germany, Austria and Switzerland, we aimed to assess whether a farming environment in childhood is protective against allergic diseases in Poland and whether specific exposures explain any protective effect.

METHODS

In rural Poland, 23 331 families of schoolchildren completed a questionnaire enquiring into farming practices and allergic diseases (Phase I). A subsample (n = 2586) participated in Phase II involving a more detailed questionnaire on specific farm exposures with objective measures of atopy.

RESULTS

Farming differed between Poland and the Alpine centres; in the latter, cattle farming was prevalent, whereas in Poland 18% of village farms kept ≥1 cow and 34% kept ≥1 pig. Polish children in villages had lower prevalences of asthma and hay fever than children from towns, and in the Phase II population, farm children had a reduced risk of atopy measured by IgE (aOR = 0.72, 95% CI 0.57, 0.91) and skin prick test (aOR = 0.65, 95% CI 0.50, 0.86). Early-life contact with grain was inversely related to the risk of atopy measured by IgE (aOR = 0.66, 95% CI 0.47, 0.92) and appeared to explain part of the farming effect.

CONCLUSION

While farming in Poland differed from that in the Alpine areas as did the exposure-response associations, we found in communities engaged in small-scale, mixed farming, there was a protective farming effect against objective measures of atopy potentially related to contact with grain or associated farm activities.

Farm exposure and time trends in early childhood may influence DNA methylation in genes related to asthma and allergy

BACKGROUND

Genetic susceptibility and environmental influences are important contributors to the development of asthma and atopic diseases. Epigenetic mechanisms may facilitate gene by environment interactions in these diseases.

METHODS

We studied the rural birth cohort PASTURE (Protection against allergy: study in rural environments) to investigate (a) whether epigenetic patterns in asthma candidate genes are influenced by farm exposure in general, (b) change over the first years of life, and (c) whether these changes may contribute to the development of asthma. DNA was extracted from cord blood and whole blood collected at the age of 4.5 years in 46 samples per time point. DNA methylation in 23 regions in ten candidate genes (ORMDL1, ORMDL2, ORMDL3, CHI3L1, RAD50, IL13, IL4, STAT6, FOXP3, and RUNX3) was assessed by pyrosequencing, and differences between strata were analyzed by nonparametric Wilcoxon-Mann-Whitney tests.

RESULTS

In cord blood, regions in ORMDL1 and STAT6 were hypomethylated in DNA from farmers' as compared to nonfarmers' children, while regions in RAD50 and IL13 were hypermethylated (lowest P-value (STAT6) = 0.001). Changes in methylation over time occurred in 15 gene regions (lowest P-value (IL13) = 1.57*10(-8)). Interestingly, these differences clustered in the genes highly associated with asthma (ORMDL family) and IgE regulation (RAD50, IL13, and IL4), but not in the T-regulatory genes (FOXP3, RUNX3).

CONCLUSIONS

In this first pilot study, DNA methylation patterns change significantly in early childhood in specific asthma- and allergy-related genes in peripheral blood cells, and early exposure to farm environment seems to influence methylation patterns in distinct genes.

Short communication: appropriate and alternative methods to determine viable bacterial counts in cow milk samples

Farm milk consumption is reported to be inversely related to the development of asthma and atopy in children and it has been hypothesized that microorganisms in milk might contribute to this protective effect. The GABRIEL study was designed to investigate this hypothesis in a large population of European children, calling for a rapid alternative to classical culture techniques to determine bacteriological properties of milk samples. One objective was to evaluate 2 different rapid methods to determine bacteriological properties in a large number of cow milk samples collected under field conditions. BactoScan (Foss Analytical, Hillerød, Denmark), an automated standard flow cytometric method utilized for routine testing of milk quality, and TEMPO (bioMérieux, Marcy l'Etoile, France), an automated most-probable-number method, were used to assess the total viable bacterial count in farm and commercial milk samples. Both methods were compared with standard plate count method and each other. Measurements based on the TEMPO method were in good agreement with the standard plate count method and showed reliable results, whereas BactoScan results did not correlate with standard plate count measurements and yielded higher bacteria counts in heat-treated milk samples compared with raw milk samples. Most likely, these discrepant results were due to inferences with staining reactions and detection of bacteria in heat-treated milk samples. We conclude that, in contrast to the routinely used BactoScan method, the TEMPO method is an inexpensive and rapid alternative to standard culture methods suitable to assess total bacterial counts in processed and raw milk samples.

The role of RET genomic variants in infantile hypertrophic pyloric stenosis

Infantile hypertrophic pyloric stenosis (IHPS) is a common childhood pathology affecting approximately 1-5 children pro 1000 newborns, with a genetic background as suggested by the familial occurrence. RET is a candidate gene for IHPS due to its role in the development of the intrinsic innervation and ganglia of the smooth musculature and the association of RET variants with another motility disorder (Hirschsprung's disease). Accordingly, we investigated RET-IHPS associations through sequencing of the complete RET coding region in 32 IHPS patients. Genotype frequencies were compared between patients and 48 controls using the Cochran-Armitage trend test or Fischer's test for exact p-values. We found 19 RET variants in IHPS, including polymorphisms in the promoter region (c.-200 G>A and c.-196 C>A). There was no statistically significant difference between the frequencies of the variants in both groups. There was no deviation from the Hardy-Weinberg equilibrium, yet a significant correlation (linkage disequilibrium) for variants in the promoter region, in exons 11, 13, 14 and 19 and in the 3' UTR. We conclude that RET variants are present in IHPS patients yet show no significant statistical association with the IHPS phenotype, suggesting at best an adjuvant role for RET in IHPS.

International variations in associations of allergic markers and diseases in children: ISAAC Phase Two

BACKGROUND

Circulating allergen-specific IgE (sIgE) and skin prick tests (SPT) are used to define atopy. Downregulation of local inflammatory responsiveness has been proposed to explain a low prevalence of positive SPTs in less affluent countries. We analysed the association between SPTs, total and allergen-specific IgE and their relationships to allergic symptoms in centres with diverse living conditions.

METHODS

Cross-sectional studies of stratified random samples of 8 to 12-year-old children (n = 7461) used the standardized methodology of Phase Two of the International Study of Asthma and Allergies in Childhood (ISAAC). Symptoms of asthma, rhinitis and eczema were ascertained by parental questionnaires. Skin examination, hypertonic saline bronchial challenge, six aeroallergen SPTs and measurements of serum total IgE and sIgE were performed.

RESULTS

In nonaffluent countries, a higher proportion of children with positive SPT had no detectable sIgE (range 37-61%) than in affluent countries (0-37%). Total serum IgE was associated with all disease outcomes among children with both positive SPT and sIgE (P < 0.001), but only with self-reported eczema in children with negative SPTs and negative sIgE.

CONCLUSIONS

The international pattern of discordance between SPT and sIgE results did not support the downregulation hypothesis. Among children with no evidence of sensitization to common aeroallergens, increased total IgE contributes little to the risk of wheeze and rhinitis in the general population but may play a role in eczema.

A multi-centre study of candidate genes for wheeze and allergy: the International Study of Asthma and Allergies in Childhood Phase 2

BACKGROUND

Common polymorphisms have been identified in genes suspected to play a role in asthma. We investigated their associations with wheeze and allergy in a case-control sample from Phase 2 of the International Study of Asthma and Allergies in Childhood.

METHODS

We compared 1105 wheezing and 3137 non-wheezing children aged 8-12 years from 17 study centres in 13 countries. Genotyping of 55 candidate single nucleotide polymorphisms (SNPs) in 14 genes was performed using the Sequenom System. Logistic regression models were fitted separately for each centre and each SNP. A combined per allele odds ratio and measures of heterogeneity between centres were derived by random effects meta-analysis.

RESULTS

Significant associations with wheeze in the past year were detected in only four genes (IL4R, TLR4, MS4A2, TLR9, P<0.05), with per allele odds ratios generally <1.3. Variants in IL4R and TLR4 were also related to allergen-specific IgE, while polymorphisms in FCER1B (MS4A2) and TLR9 were not. There were also highly significant associations (P<0.001) between SPINK5 variants and visible eczema (but not IgE levels) and between IL13 variants and total IgE. Heterogeneity of effects across centres was rare, despite differences in allele frequencies.

CONCLUSIONS

Despite the biological plausibility of IgE-related mechanisms in asthma, very few of the tested candidates showed evidence of association with both wheeze and increased IgE levels. We were unable to confirm associations of the positional candidates DPP10 and PHF11 with wheeze, although our study had ample power to detect the expected associations of IL13 variants with IgE and SPINK5 variants with eczema.

Asthma and allergic symptoms in relation to house dust endotoxin: Phase Two of the International Study on Asthma and Allergies in Childhood (ISAAC II)

BACKGROUND

Several studies have consistently reported inverse associations between exposure to endotoxin in house dust and atopy. With regard to the association between house dust endotoxin and asthma, the results are inconsistent.

OBJECTIVES

To study the association between house dust endotoxin levels and respiratory symptoms and atopy in populations from largely different countries.

METHODS

Data were collected within the International Study on Asthma and Allergies in Childhood Phase Two, a multi-centre cross-sectional study of 840 children aged 9-12 years from six centres in the five countries of Albania, Italy, New Zealand, Sweden and the United Kingdom. Living room floor dust was collected and analysed for endotoxin. Health end-points and demographics were assessed by standardized questionnaires. Atopy was assessed by measurements of allergen-specific IgE against a panel of inhalant allergens. Associations between house dust endotoxin and health outcomes were analysed by logistic regression. Odds ratios (ORs) were presented for an overall interquartile range increase in exposure.

RESULTS

Many associations between house dust endotoxin in living room floor dust and health outcomes varied between countries. Combined across countries, endotoxin levels were inversely associated with asthma ever [adjusted OR (95% confidence interval (CI)) 0.53 (0.29-0.96) for endotoxin levels per m(2) of living room floor] and current wheeze [adjusted OR (95% CI) 0.77 (0.64-0.93) for endotoxin levels per gram of living room floor dust]. There were inverse associations between endotoxin concentrations and atopy, which were statistically significant in unadjusted analyses, but not after adjustment for gender, parental allergies, cat and house dust mite allergens. No associations were found with dust quantity and between endotoxin exposure and hayfever.

CONCLUSION

These findings suggest an inverse association between endotoxin levels in living room floor dust and asthma in children.

Human blood late outgrowth endothelial cells for gene therapy of cancer: determinants of efficacy

Human adult blood late outgrowth endothelial cells (BOECs) are potential yet untested cellular vehicles to target tumor-cytotoxic effectors to tumors. We show that, following intravenous injection into irradiated mice, BOECs home to Lewis lung carcinoma (LLC) lung metastases, but less so to liver or kidney metastases. BOECs targeted most but not all of the lung metastases, to a different degree. While most of the homed BOECs took up an extravascular position, some integrated into tumor vessels. Sequestration into normal tissue was low. Placental growth factor mediated both migration and invasion of BOECs into LLC spheroid masses in vitro, as did VEGF. When armed with a suicide gene, BOECs exerted a bystander effect on LLC cells in vitro and in vivo. Surprisingly, i.v. administration of armed BOECs into mice bearing multi-organ LLC metastases did not prolong survival. In addition to homing efficacy other parameters impacted upon the efficacy of BOECs. These include the ultimate susceptibility of BOECs to suicide gene-induced cell death, their paracrine proliferative effect on LLC cells and their low proliferation rate compared to LLC cells. Addressing these determinants may make BOECs a useful addition to the arsenal of tumor-targeting moieties.

Smoking and the incidence of asthma during adolescence: results of a large cohort study in Germany

BACKGROUND

The association between smoking and asthma or wheeze has been extensively studied in cross sectional studies, but evidence from large prospective cohort studies on the incidence of asthma during adolescence is scarce.

METHODS

We report data from a cohort study in two German cities, Dresden and Munich. The study population (n = 2936) was first studied in 1995/6 at age 9-11 years as part of phase II of the International Study of Asthma and Allergies in Childhood (ISAAC II) and followed up in 2002/3. At baseline the parents completed a questionnaire and children underwent clinical examination and blood sampling. At follow up the young adults completed questionnaires on respiratory health, living, and exposure conditions. Incidence risk ratios (IRR) were calculated and adjusted for potential confounders using a modified Poisson regression approach.

RESULTS

The adjusted IRR for incident wheeze for active smokers compared with non-smokers was 2.30 (95% confidence interval (CI) 1.88 to 2.82). The adjusted IRR was slightly higher for incident wheeze without a cold (2.76, 95% CI 1.99 to 3.84) and the incidence of diagnosed asthma (2.56, 95% CI 1.55 to 4.21). Analysis of duration and intensity of active smoking indicated dose dependent associations. Stratified analyses showed that the risk of incident wheeze without a cold in atopic smokers increased with decreasing plasma alpha(1)-antitrypsin levels at baseline (1.64, 95% CI 1.22 to 2.20 per interquartile range).

CONCLUSIONS

Active smoking is an important risk factor for the incidence of asthma during adolescence. Relatively lower plasma levels of alpha(1)-antitrypsin, although well above currently accepted thresholds, may increase susceptibility to respiratory disease among atopic smokers.