Exploring the Effects of Environmental Factors on the Development of 0-4-Year Old Children in The Netherlands.

Air pollution, noise, and green space are important environmental exposures, having been linked to a variety of specific health outcomes. However, there are few studies addressing overall early life development. To assess their effects, associations between developmental milestones for a large population of 0-4-year old children in The Netherlands and environmental exposures were explored. Developmental milestones and background characteristics were provided by Preventive Child Health Care (PCHC) and supplemented with data from Statistics Netherlands. Milestones were summarized and standardized into an aggregate score measuring global development. Four age groups were selected. Environmental exposures were assigned to geocoded addresses using publicly available maps for PM2.5, PM10, PMcoarse, NO2, EC, road traffic noise, and green space. Associations were investigated using single and multiple-exposure logistic regression models. 43,916 PCHC visits by 29,524 children were available. No consistent associations were found for air pollution and road traffic noise. Green space was positively associated in single and multiple-exposure models although it was not significant in all age groups (OR 1.01 (0.95; 1.08) (1 year) to 1.07 (1.01; 1.14) (2 years)). No consistent associations were found between air pollution, road traffic noise, and global child development. A positive association of green space was indicated.

High resolution exposure modelling of heat and air pollution and the impact on mortality.

BACKGROUND: Elevated temperature and air pollution have been associated with increased mortality. Exposure to heat and air pollution, as well as the density of vulnerable groups varies within cities. The objective was to investigate the extent of neighbourhood differences in mortality risk due to heat and air pollution in a city with a temperate maritime climate. METHODS: A case-crossover design was used to study associations between heat, air pollution and mortality. Different thermal indicators and air pollutants (PM10, NO2, O3) were reconstructed at high spatial resolution to improve exposure classification. Daily exposures were linked to individual mortality cases over a 15year period. RESULTS: Significant interaction between maximum air temperature (Tamax) and PM10 was observed. During "summer smog" days (Tamax>25°C and PM10>50µg/m(3)), the mortality risk at lag 2 was 7% higher compared to the reference (Tamax 15°C and PM10 15µg/m(3)). Persons above age 85 living alone were at highest risk. CONCLUSION: We found significant synergistic effects of high temperatures and air pollution on mortality. Single living elderly were the most vulnerable group. Due to spatial differences in temperature and air pollution, mortality risks varied substantially between neighbourhoods, with a difference up to 7%.

Bis(tributyltin)oxide (TBTO) decreases the food allergic response against peanut and ovalbumin in Brown Norway rats.

Other factors than the allergen itself may be of importance in the development of food allergy. This report describes the influence of the immunosuppressive compound bis(tributyltin)oxide (TBTO), present in the food chain, on the development of food allergy to peanut or ovalbumin in Brown Norway (BN) rats. To study these effects BN rats were sensitized to either 1 or 10mg peanut or ovalbumin by daily oral gavage and the TBTO-groups were fed a diet containing 80 mg TBTO per kg diet. Co-exposure to TBTO not only resulted in decreased general immunologic parameters such as weights of mesenteric lymph nodes and Peyer's patches, lymphocyte proliferation rates in splenocytes, but also on allergic parameters. In the peanut allergen-model TBTO decreased allergen-specific Th2 cytokine production by spleen cells, number of eosinophilic and basophilic granulocytes in the blood and production of mast cell protease II after oral food challenge. In the ovalbumin allergen-model TBTO decreased the number of eosinophilic and basophilic granulocytes, allergen-specific IgE and production of mast cell protease II after oral food challenge. The data imply that in the process of risk assessment of food allergy attention should be given to immunomodulating compounds present in the diet.

The importance of dietary control in the development of a peanut allergy model in Brown Norway rats.

This report describes the further development of a peanut allergy model in Brown Norway (BN) rats and in particular the importance of allergen-free breeding of the laboratory animals for the allergen to be used. For this purpose BN rats were bred for 3 generations on soy- and peanut-free feed since it is known that the legumes peanut and soy are cross-reactive. In addition, the effect of cholera toxin (CT), an oral adjuvant often used to increase the sensitivity of food allergy models, was investigated in the BN rat model. BN rats that were bred on both soy- and peanut-free feed could be sensitized orally to peanut (all exposed rats developed peanut-specific IgE, IgG2a and IgG1) and the adjuvant CT could only enhance this sensitization to a limited extent. We also found different protein recognition patterns against purified peanut allergens (Ara h1, Ara h2 and Ara h3) between intraperitoneally (i.p.) and orally sensitized BN rats. Orally sensitized rats recognized all tested allergens whereas i.p. sensitized rats only recognized Ara h1 and Ara h2. Our conclusion is that a model for food allergy should preferably be (A) oral and (B) if possible without the use of adjuvantia. Our model in BN rats unites these preferred characteristics. In addition, we show the importance of dietary control when conducting oral sensitization studies. Special attention must be paid to unscheduled dietary pre-exposure of the animals to the protein under investigation to obtain optimal oral sensitization.