Anna Kilanowski

and 12 more

Background It has been hypothesized that epigenomic modifications such as genomic methylation changes are an intermediate step linking environmental exposures with allergic disease development. Associations between individual DNA methylation CpG sites and allergic diseases have been reported, but they have not been assessed regarding their joint predictive capability. Methods Data were obtained from 240 children of the German LISA cohort. Blood-based DNA methylation was measured at six and ten years. Aeroallergen sensitization, at least RAST class 1, was measured in blood at six, ten and 15 years. We calculated six methylation risk scores (MRS) for allergy-related phenotypes based on available publications and assessed their performance both cross-sectionally and prospectively. Dose-response associations between aeroallergen sensitization and MRS, their correlation and mapping of common hits were evaluated. Results All six atopy-related MRS were highly correlated (r>0.86) and seven CpGs were included in more than one MRS. Cross-sectionally, we observed an 80% increased risk for aeroallergen sensitization at six years with an increased risk score by one standard deviation (best MRS: relative risk = 1.81, 95% confidence interval = [1.43; 2.27]). Significant associations were also seen at ten years and in prospective models, though the effect of the latter was attenuated when only including participants not sensitized at baseline. A clear dose-response relationship with RAST classes of aeroallergen sensitization could be established cross-sectionally, but not prospectively. Conclusion We found good classification and prediction capabilities of calculated allergy-related MRS, particularly cross-sectionally for the allergy prevalence, underlining the relevance of altered gene-regulation in allergic diseases.

Iana Markevych

and 8 more

Background: We investigated whether residing in places with higher greenness, more trees and more allergenic trees early in life increases the risk of allergic outcomes, and whether these associations differ depending on the concentration of air pollutants. Methods: The analytic sample included 631 children from the German birth cohort LISA Leipzig. Asthma and allergic rhinitis, sensitization to aeroallergens and food allergens, as well as confounders, were collected prospectively up to 15 years. Greenness was assessed by Normalized Difference Vegetation Index (NDVI). A tree registry was used to derive information on trees, which were classified into allergenic and non-allergenic. Annual average concentrations of nitrogen dioxide (NO2) and ozone were also used. Geographic exposures were assigned to home addresses at birth. Longitudinal associations were analysed using generalized estimating equations. Results: Medium and high numbers (tertiles) of trees and allergenic trees in a 500 m buffer around birth addresses were associated with increased odds of allergic rhinitis up to 15 years regardless of NDVI. These exposures were also related to higher odds of sensitization to aeroallergens. Associations with asthma and sensitization to food allergens were less consistent. Effect estimates for allergic rhinitis were stronger in the high tertile of NO2 compared to the low tertile, while an opposite tendency was observed for ozone. Conclusion: We observed that early life residence in places with many trees, and allergenic trees specifically, may increase the prevalence of allergic rhinitis later in life. This association and its modification by air pollution should be pursued in further studies.