Green areas around homes reduce atopic sensitization in children.

BACKGROUND: Western lifestyle is associated with high prevalence of allergy, asthma and other chronic inflammatory disorders. To explain this association, we tested the 'biodiversity hypothesis', which posits that reduced contact of children with environmental biodiversity, including environmental microbiota in natural habitats, has adverse consequences on the assembly of human commensal microbiota and its contribution to immune tolerance. METHODS: We analysed four study cohorts from Finland and Estonia (n = 1044) comprising children and adolescents aged 0.5-20 years. The prevalence of atopic sensitization was assessed by measuring serum IgE specific to inhalant allergens. We calculated the proportion of five land-use types--forest, agricultural land, built areas, wetlands and water bodies--in the landscape around the homes using the CORINE2006 classification. RESULTS: The cover of forest and agricultural land within 2-5 km from the home was inversely and significantly associated with atopic sensitization. This relationship was observed for children 6 years of age and older. Land-use pattern explained 20% of the variation in the relative abundance of Proteobacteria on the skin of healthy individuals, supporting the hypothesis of a strong environmental effect on the commensal microbiota. CONCLUSIONS: The amount of green environment (forest and agricultural land) around homes was inversely associated with the risk of atopic sensitization in children. The results indicate that early-life exposure to green environments is especially important. The environmental effect may be mediated via the effect of environmental microbiota on the commensal microbiota influencing immunotolerance.

Analysis of chromosomal aberrations, sister-chromatid exchanges and micronuclei in peripheral lymphocytes of pharmacists before and after working with cytostatic drugs.

The frequencies of chromosome aberrations, SCEs and micronuclei (cytokinesis-block method) in blood lymphocytes were compared among six nonsmoking female pharmacists before and after 1 year of working with cytostatic drugs. All possible precautions were taken to avoid exposure to cytostatics, including proper protective clothing and a monitored, negative-pressured working environment with vertical laminar flow cabinet. As referents, an age-matched group of six nonsmoking female hospital workers not dealing with cytostatics was simultaneously sampled twice with the same time interval. The pharmacists showed a marginally higher mean frequency of SCEs/cell (6.3; P = 0.049) after the working period than 1 year earlier (5.8). On the other hand, the referents, with no obvious exposure, had a higher mean number of cells with chromatid-type aberrations, gaps excluded, in the second sampling (2.0%; P = 0.048) than in the first one (0.5%). In addition, a slight (P = 0.055) trend towards a higher frequency of micronucleated binucleate cells was observed in the second sampling for both the exposed and control subjects. As such findings suggest technical variation in the cytogenetic parameters, the small difference observed in SCEs for the pharmacists between the two samplings was probably not related to the cytostatics exposure. No statistically significant differences were observed for any of the cytogenetic parameters in comparisons between the pharmacists and the referents. The findings suggest that caution should be exercised in comparing results obtained from two different samplings in prospective cytogenetic studies.