Air pollution and cytokine responsiveness in asthmatic and non-asthmatic children.

Epidemiological studies indicate that asthmatic children are more susceptible to traffic-related air pollution exposure than non-asthmatic children. Local and systemic inflammation in combination with oxidative stress have been suggested as a possible susceptibility factor. We investigated effect modification by asthma status for the association between air pollution exposure and systemic effects using whole blood cytokine responsiveness as an inflammatory marker. The study was nested within the two German birth cohort studies GINIplus and LISAplus and initially designed as a random sub-sample enriched with asthmatic children. Using data from 27 asthmatic and 59 non-asthmatic six-year-old children we measured the production of Interleukin-6 (IL)-6, IL-8, IL-10, monocyte chemotactic protein-1 (MCP-1), tumour necrosis factor-alpha (TNF-alpha) and interferon-gamma (IFN-gamma) in whole blood after ex-vivo stimulation with urban particulate matter (EHC-93). Air pollution exposure (nitrogen dioxide (NO2), nitrogen oxides (NOx), particulate matter with an aerodynamic diameter <10µm (PM10), particulate matter with an aerodynamic diameter <2.5µm (PM2.5mass), coarse particulate matter (PMcoarse) and PM2.5absorbance (PM2.5abs)) was modelled for children´s home addresses applying land-use regression. To assess effect modification by asthma status linear regression models with multiplicative interaction terms were used. In asthmatics exposure to NO2 was associated with higher production of pro-inflammatory cytokines: adjusted means ratio (MR) 2.22 (95% confidence interval 1.22-4.04) for IL-6 per 2.68µg/m³ NO2. The interaction term between asthma status and NO2 exposure was significant. Results for NOx, PM10, PM2.5mass and PM2.5abs were in the same direction. No association between air pollution and cytokine responsiveness was found in the group of non-asthmatic children and in the overall group. Traffic-related air pollution exposure is associated with higher pro-inflammatory cytokine responsiveness in whole blood of asthmatic children.

Allergies in high-risk schoolchildren after early intervention with cow's milk protein hydrolysates: 10-year results from the German Infant Nutritional Intervention (GINI) study.

BACKGROUND: The long-term effect of nutritional intervention with hydrolysate infant formulas on allergic manifestations in high-risk children is uncertain. OBJECTIVE: We sought to investigate the effect of hydrolysate infant formulas on allergic phenotypes in children with family history of allergies at school age. METHODS: We analyzed data from participants of the prospective German Infant Nutritional Intervention study after 10 years of follow-up. At birth, children were randomly assigned to receive, for the first 4 months, one of 4 blinded formulas as breast milk substitute, if necessary: partially hydrolyzed whey formula (pHF-W), extensively hydrolyzed whey formula (eHF-W), extensively hydrolyzed casein formula (eHF-C), or standard cow's milk formula. Outcomes were parent-reported, physician-diagnosed allergic diseases. Log-binomial regression models were used for statistical analysis. RESULTS: The relative risk for the cumulative incidence of any allergic disease in the intention-to-treat analysis (n = 2252) was 0.87 (95% CI, 0.77-0.99) for pHF-W, 0.94 (95% CI, 0.83-1.07) for eHF-W, and 0.83 (95% CI, 0.72-0.95) for eHF-C compared with standard cow's milk formula. The corresponding figures for atopic eczema/dermatits (AD) were 0.82 (95% CI, 0.68-1.00), 0.91 (95% CI, 0.76-1.10), and 0.72 (95% CI, 0.58-0.88), respectively. In the per-protocol analysis (n = 988) effects were stronger. The period prevalence of AD at 7 to 10 years was significantly reduced with eHF-C in this analysis, but there was no preventive effect on asthma or allergic rhinitis. CONCLUSION: The significant preventive effect on the cumulative incidence of allergic diseases, particularly AD, with pHF-W and eHF-C persisted until 10 years without rebound, whereas eHF-W showed no significant risk reduction. There is insufficient evidence of ongoing preventive activity at 7 to 10 years of age.

The hygiene hypothesis does not apply to atopic eczema in childhood.

There is evidence that environmental factors are important for the development of eczema. Different mechanisms have been discussed in the literature, the best known of which is the hygiene hypothesis. However, epidemiological data give reason for questioning this hypothesis with regard to childhood eczema. We present results from two German birth cohort studies (LISAplus and GINIplus) concerning regional prevalence patterns of eczema and the association of eczema with day care center attendance and older siblings. Our findings are not in line with the hygiene hypothesis and question its validity with regard to eczema. It seems reasonable to assume that the effect of environmental factors is somehow disease-specific.

Elder siblings enhance the effect of filaggrin mutations on childhood eczema: results from the 2 birth cohort studies LISAplus and GINIplus.

BACKGROUND: Several studies showed a protective effect of elder siblings on eczema development, which is in line with the hygiene hypothesis. However, findings are not consistent, and there might exist different causal pathways for the development of eczema. Especially barrier disturbances as found in children with mutations in the filaggrin gene (FLG) seem to play an important role. OBJECTIVES: To investigate the interaction between FLG mutations and the presence of elder siblings on the development of eczema in 2 independent birth cohorts. METHODS: We used data from 2 German birth cohorts (LISAplus, GINIplus) up to the age of 6 years. Genotyping for FLG mutations (R501X, 2282del4) was performed in 1039 (LISAplus) and 1828 (GINIplus) children. Data on eczema (diagnosis and symptoms) and elder siblings were obtained by parental questionnaires. The association among eczema, FLG mutations, and elder siblings was analyzed longitudinally by using generalized estimating equations. RESULTS: We found no protective effect of elder siblings on eczema development. On the contrary, children with FLG mutations had a significantly higher risk for eczema if they had elder siblings. Attending day care centers lessened this effect. After excluding 303 children who attended early day care, the odds ratio for interaction between FLG mutations and elder siblings was 3.27 (95% CI, 1.14-9.36) in LISAplus and 2.41 (95% CI, 1.06-5.48) in GINIplus. CONCLUSION: Our findings did not confirm a protective sibling effect. The prevalence of eczema in children with filaggrin deficiency was higher if elder siblings were present. Our results give evidence for complex skin-driven pathogenic mechanisms that might be different depending on children's genetic backgrounds.

Preventive effect of hydrolyzed infant formulas persists until age 6 years: long-term results from the German Infant Nutritional Intervention Study (GINI).

BACKGROUND: The long-term effect of nutritional intervention with hydrolyzed infant formulas on allergy development has not been sufficiently evaluated. OBJECTIVE: We performed a follow-up of the German Infant Nutritional Intervention study until 6 years of life to investigate the long-term allergy-preventive effect of 3 hydrolyzed infant formulas compared with cow's milk formula (CMF) in a randomized, double-blind trial. METHODS: Between 1995 and 1998, 2252 newborns with atopic heredity were randomly assigned at birth to receive one of 4 blinded formulas: partially or extensively hydrolyzed whey formula, extensively hydrolyzed casein formula, or CMF as milk substitute for the first 4 months when breast-feeding was insufficient. The cohort was followed from birth until 6 years of age with yearly questionnaires. Outcomes were physician-diagnosed allergic diseases (atopic dermatitis, food allergy, allergic urticaria, asthma, and hay fever/allergic rhinitis). Log-binomial regression modeled with generalized estimation equations was used for the statistical analysis. RESULTS: In the intent-to-treat analysis the relative risk of a physician's diagnosis of allergic manifestation (AM) compared with CMF was 0.82 (95% CI, 0.70-0.96) for partially hydrolyzed whey formula, 0.90 (95% CI, 0.78-1.04) for extensively hydrolyzed whey formula, and 0.80 (95% CI, 0.69-0.93) for extensively hydrolyzed casein formula. The corresponding figures for atopic eczema were 0.79 (95% CI, 0.64-0.97), 0.92 (95% CI, 0.76-1.11), and 0.71 (95% CI, 0.58-0.88), respectively. In the per-protocol analysis all effects were stronger and significant. No significant effect on other AMs was found. CONCLUSION: The data confirm a long-term allergy-preventive effect of hydrolyzed infant formulas on AM and atopic eczema until 6 years of age.

Day care in relation to respiratory-tract and gastrointestinal infections in a German birth cohort study.

AIM: To describe day care attendance in Germany today (in former East and former West Germany). To investigate longitudinally whether children attending day care centres have an increased risk of acquiring common cold, bronchitis, pneumonia, otitis media or diarrhea. METHODS: Questionnaire information was collected when the children in the cohort were 6, 12, 18, 24 months, and 4 and 6 years old. Day care within the first and first 2 years of life was investigated longitudinally with GEE (generalised estimating equations) methods in relation to common cold, bronchitis, pneumonia, otitis media and diarrhea within the first 6 years of life. RESULTS: Day care centre attendance is more common in former East than in former West Germany; this difference is evident even 10-12 years after German reunification. Children attending a day care centre were more likely to have common cold, bronchitis, pneumonia, otitis media and diarrhea within the first 2-3 years of life. With the exception of common cold, from year 4 onwards these associations were not statistically significant anymore and even reversed for some of the infections. CONCLUSIONS: Children attending day care centres were at an increased risk of respiratory and gastrointestinal infections within the first years of life. However, around school age these differences disappeared or even partly reversed.

Determinants of children's exposure to environmental tobacco smoke (ETS): a study in Southern Germany.

Maternal smoking has been repeatedly found to be the most important determinant of children's exposure to environmental tobacco smoke (ETS). Here, we further investigated predictors for the urinary cotinine/creatinine ratio (CCR, ng/mg) in 1220 preschool children for the year 1996. Children from smoking homes (35.1%) had significantly higher CCR than children from nonsmoking homes (mean: 55.5 vs. 14.9 ng/mg). The level of education of the parents was a strong predictor for CCRs even after adjusting for number of cigarettes smoked, maternal smoking and dwelling space. Additionally, dwelling space was inversely related to children's urinary cotinine level. The CCR- levels in children investigated in 1996 and 1998 were significantly correlated (Pearson's r=0.67). The parents of 806 children agreed for a visit to their homes. In 79 of the 536 (14.7%) of the self-reported, nonsmoking households, smoking was admitted during the visit. The mean urinary CCR of these children was 25.2 ng/mg. We conclude that in addition to parental smoking behaviour, other variables such as dwelling space and social and educational status predict the children's exposure to ETS. Our data also revealed that a considerable percentage of parents denied the ETS exposure of their children at home.