FADS gene cluster modulates the effect of breastfeeding on asthma. Results from the GINIplus and LISAplus studies.

BACKGROUND: The protective effect of breastfeeding (BF) on the development of asthma has been widely recognized, even if not all results have been consistent. Gene variants of the FADS gene cluster have a major impact on fatty acid composition in blood and in breast milk. Therefore, we evaluated the influence of the FADS1 FADS2 gene cluster polymorphisms on the association between BF and asthma. METHODS: The analysis was based on data (N=2245) from two German prospective birth cohort studies. Information on asthma and BF during the first 6 months was collected using questionnaires completed by the parents. Logistic regression modelling was used to analyse the association between exclusive BF and ever having asthma stratified by genotype. RESULTS: In the stratified analyses, BF for 3 or 4 months after birth had a protective effect for heterozygous and homozygous carriers of the minor allele (adjusted odds ratio between 0.37 (95% CI: 0.18-0.80) and 0.42 (95% CI: 0.20-0.88). Interaction terms of BF with genotype were significant and ranged from -1.17 (P-value: 0.015) to -1.33 (0.0066). Moreover, heterozygous and homozygous carriers of the minor allele who were exclusively breastfed for 5 or 6 months after birth had a reduced risk of asthma [0.32 (0.18-0.57) to 0.47 (0.27-0.81)] in the stratified analyses. For individuals carrying the homozygous major allele, BF showed no significant effect on the development of asthma. CONCLUSIONS: The association between exclusive BF and asthma is modified by the genetic variants of FADS genotypes in children.

Respiratory health in children, and indoor exposure to (1,3)-ß-D-glucan, EPS mould components and endotoxin.

For a long time, exposure to mould and dampness-derived microbial components was considered a risk factor for the development of respiratory diseases and symptoms. Some recent studies suggested that early childhood exposure to mould components, such as (1,3)-ß-D-glucan and extracellular polysaccharides (EPSs), may protect children from developing allergy. We investigated the association of exposure to (1,3)-ß-D-glucan, EPS and endotoxin with asthma and allergies in 6-yr-old children. This investigation was the follow-up to a nested case-control study among three European birth cohorts. Children from two ongoing birth cohort studies performed in Germany (n = 358) and one in the Netherlands (n = 338) were selected. Levels of (1,3)-ß-D-glucan, EPS and endotoxin were measured in settled house dust sampled from children's mattresses and living-room floors when the children were, on average, 5 yrs of age. At the age of 6 yrs, health outcome information was available for 678 children. In the two German subsets, domestic EPS and endotoxin exposure from children's mattresses were significantly negatively associated with physician-diagnosed asthma (OR per interquartile range increase 0.60 (95% CI 0.39-0.92) and 0.55 (95% CI 0.31-0.97), respectively). In addition, EPS exposure was inversely related to physician-diagnosed allergic rhinitis (OR 0.50, 95% CI 0.31-0.81). For the Dutch population, no associations were observed between exposure to microbial agents and respiratory health outcomes. We found inverse associations between domestic exposure to EPS and endotoxin from children's mattresses, and doctor-diagnosed asthma and rhinitis in German, but not in Dutch, school children. The reasons for the differences between countries are not clear.

FADS gene variants modulate the effect of dietary fatty acid intake on allergic diseases in children.

BACKGROUND: The association between dietary fatty acid intake and the development of atopic diseases has been inconsistent. This could be due to inter-individual genetic differences in fatty acid metabolism. OBJECTIVE: The aim of the current study was to assess the influence of FADS1 FADS2 gene cluster polymorphisms on the association between dietary fatty acid intake and atopic diseases and allergic sensitization in 10-year-old children. METHODS: The analysis was based on data from two German prospective birth cohort studies. Data on margarine and fatty acid intake were collected using a food frequency questionnaire. Information on atopic diseases was collected using a questionnaire completed by the parents. Specific IgE against common food and inhalant allergens were measured. Six variants of the FADS1 FADS2 gene cluster (rs174545, rs174546, rs174556, rs174561, rs174575 and rs3834458) were tested. Logistic regression modelling, adjusted for gender, age, maternal education level and study centre, was used to analyse the association between fatty acid intake and atopic diseases stratified by genotype. RESULTS: No significant association was found between the six FADS single nucleotide polymorphisms (SNPs) and allergic diseases or atopic sensitization. The total n-3/total n-6 ratio was positive associated with an increased risk of hayfever in homozygous major allele carriers ranging from an adjusted odds ratios of 1.25 (95%-CI: 1.00-1.57) to 1.31 (95%-CI: 1.01-1.69) across the six tested SNPs although this association was not significant anymore after correcting for multiple testing. Daily margarine intake was significantly associated with asthma [1.17 (1.03-1.34) to 1.22 (1.06-1.40)] in individuals carrying the homozygous major allele. This association was also significant after correcting for multiple testing. CONCLUSIONS & CLINICAL RELEVANCE: The association between dietary intake of fatty acids and allergic diseases might be modulated by FADS gene variants in children.

Association between attendance of day care centres and increased prevalence of eczema in the German birth cohort study LISAplus.

BACKGROUND: Day care centre attendance is much more common in East than in West Germany. Although there is evidence that early day care might be protective against atopic diseases, several studies have shown a higher prevalence of childhood eczema in East Germany compared to West Germany. OBJECTIVES: To compare prevalence and cumulative incidence of eczema in a birth cohort study in East and West Germany and to identify risk factors that are associated with eczema, which might explain regional differences. METHODS: We used data from the ongoing population-based birth cohort study Influence of Life-style factors on the development of the Immune System and Allergies in East and West Germany Plus the influence of traffic emissions and genetics. In 1997, 3097 children from study areas in East and West Germany were recruited. Cumulative incidence and 1-year prevalences of eczema up to the age of 6 years were determined from yearly questionnaires. Cox regression and generalized estimating equations/logistic regression were used to quantify regional differences and to identify risk factors that might explain them. RESULTS: Prevalence and incidence of eczema were higher in children living in East Germany than those living in West Germany. We identified 11 risk factors that showed significant regional differences. From these factors, only 'day care attendance during the first 2 years of life' was significantly associated with eczema (odds ratio 1.56, 95% confidence interval CI 1.31-1.86). The regional differences in eczema could be explained by differences in early day care utilization. CONCLUSION: Day care centre attendance is associated with an increased prevalence and incidence of eczema. Regional differences in eczema prevalence could be explained by regional differences in utilization of early day care.

Prospective association between food sensitization and food allergy: results of the LISA birth cohort study.

BACKGROUND: Food allergy is common, especially in childhood, where 6-8% of children are affected. Identification of early and efficient markers for later development of food allergy is very important. OBJECTIVE: We examined the ability of repeated measurements of food sensitization in early childhood to predict doctor-diagnosed food allergy (DDFA) at the age of 6 years. METHODS: The analysis was based on data from a prospective birth cohort study. Information was collected by parental questionnaires, and blood samples were obtained at 2 and 6 years of age. Children with repeated determination of sensitization to food allergens at 2 and 6 years of age were categorized into the sensitization phenotypes: no, early onset, late onset and persistent sensitization. The association between sensitization phenotypes and DDFA was prospectively investigated using multiple logistic regression analyses. RESULTS: Of 3097 children recruited at birth, a complete follow-up of IgE measurements and questionnaires at 1.5, 2 and 6 years were available for 1082 children. Early food allergen sensitization (fx5) was a strong risk for DDFA at 6 years [odds ratio (OR)=4.7; 95% confidence intervals (95% CI) 2.0-11.2] and for a new onset of DDFA at 6 years (OR=4.1; 95% CI 1.5-11.3). Additionally, persistent food allergen sensitization increased the risk of DDFA at 6 years (OR=6.1; 95% CI 2.7-13.7). Early sensitized children with a history of parental atopy showed the highest risk for DDFA at 6 years. CONCLUSION: Food-sensitized children during the first 2 years of life, especially with a family history of atopy, might be considered as a susceptible subgroup that requires specific attention concerning the development of food allergy-related symptoms.

Perinatal exposure to endotoxin and the development of eczema during the first 6 years of life.

BACKGROUND: Previous studies have reported a protective association between high levels of exposure to endotoxin during infancy and the development of subsequent eczema within the first 6 months of life. AIM: To investigate the association between exposure in infancy to endotoxin from mattress dust and the development of eczema up to age of 6 years in 2166 children participating in the German Influences of Lifestyle-Related Factors on the Immune System and the Development of Allergies in Childhood (LISA) study, an ongoing population-based birth-cohort study. METHODS: Endotoxin levels in house dust samples collected at 3 months after birth were quantified using the kinetic Limulus amebocyte lysate assay. Specific IgE antibodies to common food and aeroallergens were measured using radioallergosorbent test, fluorenzyme immunoassay (Pharmacia CAP system) when children were 2 and 6 years old. Information on eczema symptoms and physician-diagnosed eczema were collected at each follow-up using a questionnaire. RESULTS: No association was found between endotoxin exposure from mattresses (the mattresses of each child and their parents were examined) during infancy and the development of eczema symptoms or doctor-diagnosed eczema by 6 years of age (OR = 1.1, 95% CI 0.5-2.3, and OR = 1.1, 95% CI 0.4-3.3, respectively). No association was found when children with only atopic eczema. CONCLUSION: Endotoxin exposure during infancy is unlikely to have a large long-term effect on the development of eczema, especially the atopic form.

Common variants in FCER1A influence total serum IgE levels from cord blood up to six years of life.

BACKGROUND: In a recent genome wide scan, a functional promoter variant (rs2251746) in the gene encoding the alpha chain of the high affinity receptor for immunoglobulin E (IgE) (FCER1A) was identified as major determinant of serum IgE levels. OBJECTIVE: The aim of this study was to investigate the role of rs2251746 on total IgE levels measured at different stages of life from birth (cord blood) up to the age of 6 and to evaluate its interaction with the environmental influences in two German birth cohorts. METHOD: Data from two German birth cohorts were analysed (n = 1043 for the LISA cohort and n = 1842 for the GINI cohort). In the studies, total serum IgE was measured from cord blood, and blood samples taken at the age of 2/3 and 6 years. In a subgroup of the LISA study, house dust samples were collected at age of 3 months and the amount of endotoxin was determined. Random effect models were used to analyse the longitudinal health outcomes. RESULTS: In the two cohorts, the heterozygote and the rare homozygote of rs2251746 was consistently associated with lower total IgE levels from birth up to the age of 6 years with an allele-dose effect (P < 0.02 for blood samples taken at each time point in both cohorts). No interaction between the two FCER1A encoding gene and environmental exposures including endotoxin, worm infestation and day care centre attendance during early childhood were observed. CONCLUSION: Common variants in FCER1A strongly influence basal IgE production independently from environmental stimuli. These effects can be observed already in cord blood pointing to altered gene expression in foetus.

Stress-related maternal factors during pregnancy in relation to childhood eczema: results from the LISA Study.

BACKGROUND: Stress has been suggested to impact the onset and exacerbation of eczema and other atopic disorders. Whether early exposure to stress-related factors might exert long-term effects remains to be clarified. OBJECTIVE: The objective of this study was to investigate whether stress-related maternal factors during pregnancy are associated with childhood eczema during the first 6 years of life. METHODS: Data from 3004 children from a prospective German birth cohort study (LISA) were analyzed. Information from maternity certificates and questionnaire information on unwanted pregnancy were used to evaluate stress-related maternal factors during pregnancy. Prevalence data for physician-diagnosed eczema were available up to the age of 6 years. RESULTS: Maternal factors during pregnancy were positively associated with childhood eczema in terms of cumulative prevalence up to the age of 2 years (adjusted odds ratio, 1.48; 95% confidence interval, 0.95-2.30) after adjusting for potential confounders. Beyond the second year no increased risk was observed. CONCLUSIONS: The results of this study suggest that stress-related maternal factors during pregnancy are associated with an increased risk of childhood eczema during the first 2 years of life. The impact of postnatal stress such as parental divorce or separation on this association could not be clarified. Future studies should therefore further elucidate how prenatal and postnatal stress interact and whether prenatal stress might have a programming effect. If future studies confirm the findings of this study, reducing maternal stress during pregnancy might be a possible target in the primary prevention of eczema during childhood.

Stressful life events in childhood and allergic sensitization.

Stressful life events evidently have an impact on development of allergic diseases, but the mechanism linking stress to pathological changes of immune system function is still not fully understood. The aim of our study was to investigate the relationship between stressful life events, neuropeptide and cytokine concentrations in children as well as the association between early stressful life events and atopic eczema (AE). Within the LISA plus (Life style - Immune system - Allergy) study, blood samples from children of 6 years of age were analyzed for concentration of the neuropeptides vasoactive intestinal peptide (VIP), somatostatin (SOM), substance P (SP) and the Th1/Th2 cytokines IFN-γ and IL-4. Life events such as severe disease or death of a family member, unemployment or divorce of the parents were assessed with a questionnaire filled in by the parents. Furthermore, lifetime prevalence of AE and incidence after the assessment period of life events were compared. Our data suggest that separation/ divorce of parents increase childrens risk of developing AE later in life. Children with separated/divorced parents showed high VIP levels and high concentrations of the Th2 cytokine IL-4 in their blood. Severe diseases and death of a family member were neither associated with neuropeptide levels nor with cytokine concentrations. Unemployment of the parents was associated with decreased IFN-γ concentrations in childrens blood but not with neuropeptide levels. Thus, the neuropeptide VIP might be a mediator between stressful life events and immune regulation contributing to the Th2-shifted immune response in children with separated/divorced parents.