Browsing by Author "Schaffner, Emmanuel"

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    Genome-wide DNA methylation in peripheral blood and long-term exposure to source-specific transportation noise and air pollution: The SAPALDIA Study
    (National Institute of Environmental Health Sciences (NIEHS), 2020-06-01) Eze, Ikenna C.; Jeong, Ayoung; Schaffner, Emmanuel; Rezwan, Faisal I.; Ghantous, Akram; Foraster, Maria; Vienneau, Danielle; Kronenberg, Florian; Herceg, Zdenko; Vineis, Paolo; Brink, Mark; Wunderli, Jean-Marc; Schindler, Christian; Cajochen, Christian; Röösli, Martin; Holloway, John W.; Imboden, Medea; Probst-Hensch, Nicole
    Background: Few epigenome-wide association studies (EWAS) on air pollutants exist, and none have been done on transportation noise exposures, which also contribute to environmental burden of disease. Objective: We performed mutually independent EWAS on transportation noise and air pollution exposures. Methods: We used data from two time points of the Swiss Cohort Study on Air Pollution and Lung and Heart Diseases in Adults (SAPALDIA) from 1,389 participants contributing 2,542 observations. We applied multiexposure linear mixed-effects regressions with participant-level random intercept to identify significant Cytosine-phosphate-Guanine (CpG) sites and differentially methylated regions (DMRs) in relation to 1-y average aircraft, railway, and road traffic day-evening-night noise (Lden); nitrogen dioxide (NO2); and particulate matter (PM) with aerodynamic diameter <2.5μm (PM2.5). We performed candidate (CpG-based; cross-systemic phenotypes, combined into “allostatic load”) and agnostic (DMR-based) pathway enrichment tests, and replicated previously reported air pollution EWAS signals. Results: We found no statistically significant CpGs at false discovery rate <0.05. However, 14, 48, 183, 8, and 71 DMRs independently associated with aircraft, railway, and road traffic Lden; NO2; and PM2.5, respectively, with minimally overlapping signals. Transportation Lden and air pollutants tendentially associated with decreased and increased methylation, respectively. We observed significant enrichment of candidate DNA methylation related to C-reactive protein and body mass index (aircraft, road traffic Lden, and PM2.5), renal function and “allostatic load” (all exposures). Agnostic functional networks related to cellular immunity, gene expression, cell growth/proliferation, cardiovascular, auditory, embryonic, and neurological systems development were enriched. We replicated increased methylation in cg08500171 (NO2) and decreased methylation in cg17629796 (PM2.5). Conclusions: Mutually independent DNA methylation was associated with source-specific transportation noise and air pollution exposures, with distinct and shared enrichments for pathways related to inflammation, cellular development, and immune responses. These findings contribute in clarifying the pathways linking these exposures and age-related diseases but need further confirmation in the context of mediation analyses. https://doi.org/10.1289/EHP6174
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    Role of DNA methylation in the association of lung function with body mass index: a two-step epigenetic Mendelian randomisation study
    (BioMed Central, 2020-06-16) Amaral, André F. S.; Imboden, Medea; Wielscher, Matthias; Rezwan, Faisal I.; Minelli, Cosetta; Garcia-Aymerich, Judith; Peralta, Gabriela P.; Auvinen, Juha; Jeong, Ayoung; Schaffner, Emmanuel; Beckmeyer-Borowko, Anna; Holloway, John W.; Jarvelin, Marjo-Riitta; Probst-Hensch, Nicole; Jarvis, Deborah L.
    Background Low lung function has been associated with increased body mass index (BMI). The aim of this study was to investigate whether the effect of BMI on lung function is mediated by DNA methylation. Methods We used individual data from 285,495 participants in four population-based cohorts: the European Community Respiratory Health Survey, the Northern Finland Birth Cohort 1966, the Swiss Study on Air Pollution and Lung Disease in Adults, and the UK Biobank. We carried out Mendelian randomisation (MR) analyses in two steps using a two-sample approach with SNPs as instrumental variables (IVs) in each step. In step 1 MR, we estimated the causal effect of BMI on peripheral blood DNA methylation (measured at genome-wide level) using 95 BMI-associated SNPs as IVs. In step 2 MR, we estimated the causal effect of DNA methylation on FEV1, FVC, and FEV1/FVC using two SNPs acting as methQTLs occurring close (in cis) to CpGs identified in the first step. These analyses were conducted after exclusion of weak IVs (F statistic < 10) and MR estimates were derived using the Wald ratio, with standard error from the delta method. Individuals whose data were used in step 1 were not included in step 2. Results In step 1, we found that BMI might have a small causal effect on DNA methylation levels (less than 1% change in methylation per 1 kg/m2 increase in BMI) at two CpGs (cg09046979 and cg12580248). In step 2, we found no evidence of a causal effect of DNA methylation at cg09046979 on lung function. We could not estimate the causal effect of DNA methylation at cg12580248 on lung function as we could not find publicly available data on the association of this CpG with SNPs. Conclusions To our knowledge, this is the first paper to report the use of a two-step MR approach to assess the role of DNA methylation in mediating the effect of a non-genetic factor on lung function. Our findings do not support a mediating effect of DNA methylation in the association of lung function with BMI.