Tiia Voor

and 8 more

Title: Atopic sensitization in childhood depends on the type of green area around the home in infancy Tiia Voor1,2*, Meelis Pärtel3*, Aleksandr Peet1,2, Liisa Saare1,2, Heikki Hyöty4,5, Mikael Knip6,7, John Davison3, Martin Zobel3#, Vallo Tillmann1,2#1 Children´s Clinic of Tartu University Hospital, Estonia2 Institute of Clinical Medicine, University of Tartu, Estonia3 Institute of Ecology and Earth Sciences, University of Tartu, Estonia4 Faculty of Medicine and Health Technology, Tampere University, Finland5 Fimlab Laboratories, Pirkanmaa Hospital District, Tampere, Finland6 Pediatric Research Center, New Children’s Hospital, Helsinki University Hospital, Helsinki, Finland7 Research Program for Clinical and Molecular Metabolism, Faculty of Medicine, University of Helsinki, Helsinki, FinlandTo the editor,The prevalence of allergy has increased worldwide (1) and a green environment is essential in developing immune responses and may protect against allergy (2, 3). However, previous studies have not distinguished the effects of different green area types.Here we tested how the type and spatial scale of green area around the infancy home are associated with atopic sensitization up to the age of 9 years.The study group comprised 280 children from the Estonian DIABIMMUNE project birth cohort (4) whose sera were measured for different allergen-specific IgE (sIgE) antibodies at the ages 0.5, 1.5, 3, and 9 years. Subjects were divided into 3 groups by sIgE results. 86 children who had at least one sIgE ≥0.7 kU/L were categorized into the group of definite atopic sensitization (Group I); 44 children had some sIgE between 0.35-0.69 kU/L and were classified as uncertain sensitization (Group II); 150 children had all measured sIgE below 0.35 KU/L, and they formed the control group (Group III). The types of surrounding green areas during the first six months of life were obtained from digital maps of Estonia. The land was divided into agricultural fields, forests, grasslands and wetlands (Figure 1A).The combination of various green area types at a radius of 1-10 km around homes in infancy was related to signs of atopy by ordinal regressions, and model weights were compared.This is the first study addressing the correlation between the land-use intensity around child homes and the development of atopic sensitization. A model with the green areas within 8 km had the highest protective weight (Fig. 1B). Among the various types of green areas, the impact of forests was the largest (Fig. 1C), but the best model also included grasslands and wetlands. Agricultural fields had an impact only at 1-2 km scales, and their weight declined strongly at larger scales (Table 1). We used the best model (area of forest, grasslands and wetlands within 8 km) and examined how it predicts atopic sensitization groups (Fig. 1D). The model predicted a decrease in Group I and an increase in control Group III. The uncertain Group II showed a slightly decreasing tendency. The protective effect of forests, grasslands and wetlands against sensitization was evident for both inhaled and food allergens.The world is urbanizing, and the isolation of humans from biodiverse green areas leads to reduced contact with beneficial environmental microbes (5). Ruokalainen et al (2) showed that the greenness around homes was negatively associated with the risk of atopy in children. Contact with natural soil enriched microbiota enhanced immune regulation and may reduce the risk of development of immune-mediated diseases (6). Our results reveal considerable differences in how various green area types might prevent atopic sensitization. The area of biodiverse land (forests, grasslands, wetlands) showed a strong protective effect, while the agricultural land did not. The positive effect of forests, grasslands and wetlands became clearer with increasing spatial scale. The relatively large distance of influence indicates that the biodiversity of beneficial microbes might need a large area.Our study has some limitations. First, we could not study the microbiota of the participants and determine whether the spatial environmental model explained microbiota composition. Secondly, we studied only atopic sensitization and did not diagnose allergic disease. This was because the data were collected using questionnaires completed by parents and were of variable quality.In conclusion, the current results indicate that biodiverse land – such as forests, grasslands, and wetlands – around homes during infancy elicits a strong protective effect against the development of atopy later in childhood. At the same time, intensive croplands have only a very weak effect.

Tiina Palmu

and 11 more

Background: Enterovirus (EV) infections, being among the most prevalent viruses worldwide, have been associated with reduced risk of allergic diseases. We sought to determine the association of EVs with allergic sensitization and disease in early childhood. Methods: The study was carried out in a nested case-control setting within a prospective birth cohort in Finland. We included 138 case children who had specific IgE (s-IgE) sensitization at the age of 5 years and 138 control children without s-IgE sensitization. Allergic disease was recorded at study visits and asked with ISAAC questionary. We screened for the presence of serotype specific antibodies against 41 EVs at 1 to 5 years of age and assessed their association with allergic sensitization and disease. Results: The overall number of EV infections did not differ between s-IgE-sensitized children and non-sensitized control children. However, there was a tendency of case children with an allergic disease having less EV infections than their controls. This observation was statistically significant for species A EVs in case children with atopic dermatitis vs. control children: OR 0.6 (95 % CI 0.36-0.99), P = 0.048. Conclusion: This study supports the evidence that EV exposure and development of allergic disease are inversely associated. Interestingly, the inverse association was not observed for bare atopic IgE sensitization, but for IgE sensitization coupled with clinical atopic disease. This suggests that environmental factors influencing IgE sensitization may differ from those influencing progression to clinical allergic disease.

Tari Haahtela

and 7 more

Increase of allergic conditions has occurred at the same pace with the Great Accleration, which stands for the rapid growth rate of human activities upon Earth from 1950s. Changes of environment and lifestyle along with escalating urbanization, are acknowledged as the main underlying causes. Secondary (tertiary) prevention for better disease control has advanced considerably with innovations for oral immunotherapy and effective treatment of inflammation with corticosteroids, calcineurin inhibitors and biologic medications. Patients are less disabled than before. However, primary prevention has remained a dilemma. Factors predicting allergy and asthma risk have proven complex: risk factors increase the risk while protective factors counteract them. Interaction of human body with environmental biodiversity with micro-organisms and biogenic compounds as well as the central role of epigenetic adaptation in immune homeostasis have given new insight. Allergic diseases are good indicators of the twisted relation to environment. In various non-communicable diseases, the protective mode of the immune system indicates low-grade inflammation without apparent cause. Giving microbes, pro- and prebiotics, has shown some promise in prevention and treatment. The real-world public health programme in Finland (2008-2018) emphasized nature relatedness and protective factors for immunological resilience, instead of avoidance. The nationwide action mitigated the allergy burden, but in the lack of controls, primary preventive effect remains to be proven. The first results of controlled biodiversity interventions are promising. In the fastly urbanizing world, new approaches are called for allergy prevention, which also has a major cost saving potential.