Helicobacter pylori in children with asthmatic conditions at school age, and their mothers.

BACKGROUND: Helicobacter pylori prevalence in Western countries has been declining simultaneously with increases in childhood asthma and allergic diseases; prior studies have linked these phenomena. AIMS: To examine the association between H. pylori colonisation in children and risk of asthma and related conditions at school age. We secondly examined additional effects of maternal H. pylori status by pairing with children's status. METHODS: This study was embedded in a multi-ethnic population-based cohort in Rotterdam, The Netherlands. We measured anti-H. pylori and anti-CagA antibodies in serum of children obtained at age 6 years, and of their mothers obtained during midpregnancy. Asthma or related conditions were reported for children at age 6 years. We used multivariate logistic regression analyses among 3797 subjects. RESULTS: In children, the H. pylori positivity rate was 8.7%, and 29.2% of these were CagA-positive. A child's colonisation with a CagA-negative-H. pylori strain was associated with an increased risk of asthma (Odds ratio 2.11; 95% CI 1.23-3.60), but this differed for European (3.64; 1.97-6.73) and non-European (0.52; 0.14-1.89) children. When taking into account maternal H. pylori status, only H. pylori-positive children with an H. pylori-negative mother had increased risk of asthma (2.42; 1.11-5.27), accounting for 3.4% of the asthma risk. CONCLUSIONS: Colonisation of a European child with a CagA-negative-H. pylori strain at age 6 was associated with an increased prevalence of asthma, but there was no association for non-European children. The underlying mechanisms for the observed risk differences require further research.

Neonatal folate, homocysteine, vitamin B12 levels and methylenetetrahydrofolate reductase variants in childhood asthma and eczema.

OBJECTIVES: To assess the associations of folate, homocysteine and vitamin B12 levels of children at birth and their methylenetetrahydrofolate reductase (MTHFR) variants with asthma and eczema in childhood. METHODS: This study was embedded in a population-based prospective cohort study (n = 2,001). Neonatal cord blood folate, homocysteine and vitamin B12 levels were measured, and MTHFR C677T and A1298C genotyped. Wheezing and physician-diagnosed eczema were annually obtained by questionnaire until 4 years. At 6 years, we collected information on physician-diagnosed asthma ever and self-reported eczema ever, measured fractional exhaled nitric oxide (FeNO), and interrupter resistance (Rint). Data were analysed with generalized estimating equations or logistic regression: continuous outcomes with linear regression models. RESULTS: Folate, homocysteine and vitamin B12 levels of children at birth were not associated with wheezing or eczema until 4 years, asthma and eczema ever, or FeNO or Rint at 6 years. In children carrying C677T mutations in MTHFR, higher folate levels were associated with an increased risk of eczema (repeated eczema until 4 years: OR 1.40 (95% CI 1.09-1.80) (SD change) P-interaction = 0.003, eczema ever at 6 years: OR 1.41 (0.97-2.03) P-interaction = 0.011). No interactions between MTHFR and child folate and homocysteine levels were observed for wheezing and asthma. CONCLUSIONS: Folate, homocysteine and vitamin B12 levels of children at birth did not affect asthma- and eczema-related outcomes up to the age of 6 years. Further studies are warranted to establish the role of MTHFR variants in these associations.

Maternal fish consumption during pregnancy and risks of wheezing and eczema in childhood: the Generation R Study.

BACKGROUND/OBJECTIVES: Maternal fish consumption during pregnancy might influence the fetal immune system through anti-inflammatory effects of omega-3 fatty acids, and might affect the risks of childhood asthma and atopy. In Generation R, a prospective cohort study in the Netherlands, we examined the associations of first trimester fish consumption with childhood wheezing and eczema in the first 4 years of life. METHODS: In total, 2976 mothers completed a 293-item semiquantitative food frequency questionnaire covering dietary intake in the first trimester. The occurrence of wheezing and eczema was yearly assessed by questionnaires. RESULTS: Median weekly fish consumption was 83 (95% range 0-316) grams per week. We observed no consistent associations of maternal total-, lean- or fatty-fish consumption during pregnancy with the risks of childhood wheezing. Maternal shellfish consumption of 1-13 g per week was associated with overall increased risks of childhood wheezing and eczema (OR 1.20 (1.04, 1.40) and OR 1.18 (1.01, 1.37), respectively). Maternal fatty fish consumption of 35-69 g per week was associated with increased overall risks of childhood eczema (OR 1.17 (1.00, 1.38)), but maternal total- or lean-fish consumption was not. CONCLUSIONS: During pregnancy, shellfish consumption was associated with increased risks of wheezing and eczema, while fatty fish consumption was associated with a higher risk of eczema only. Maternal total fish or lean fish consumption were not associated with wheezing or eczema. Further studies are needed to replicate these findings and to explore underlying mechanisms.

Duration and exclusiveness of breastfeeding and childhood asthma-related symptoms.

The aim of our study was to examine the associations of breastfeeding duration and exclusiveness with the risks of asthma-related symptoms in preschool children, and to explore whether these associations are explained by atopic or infectious mechanisms. This study was embedded in a population-based prospective cohort study of 5,368 children. Information on breastfeeding duration, exclusiveness and asthma-related symptoms, including wheezing, shortness of breath, dry cough and persistent phlegm, was obtained by questionnaires. Compared with children who were breastfed for 6 months, those who were never breastfed had overall increased risks of wheezing, shortness of breath, dry cough and persistent phlegm during the first 4 yrs (OR 1.44 (95% CI 1.24-1.66), 1.26 (1.07-1.48), 1.25 (1.08-1.44) and 1.57 (1.29-1.91), respectively). Similar associations were observed for exclusive breastfeeding. The strongest associations per symptom per year were observed for wheezing at 1 and 2 yrs. Additionally adjusted analyses showed that the associations of breastfeeding with asthma-related symptoms were not explained by eczema but partly by lower respiratory tract infections. Shorter duration and nonexclusivity of breastfeeding were associated with increased risks of asthma-related symptoms in preschool children. These associations seemed, at least partly, to be explained by infectious, but not by atopic, mechanisms.