DNA extraction, methylation profiling, and QC was performed as described in Zillich et al. [15]. In brief, DNA was extracted using the DNeasy extraction kit (Qiagen, Hilden, Germany); the Illumina HumanMethylation EPIC BeadChip and the Illumina HiScan array scanning system (Illumina, San Diego, CA) were used to determine DNA-methylation levels. We used an updated and customized version of the CPACOR pipeline to extract beta values from raw intensities [19]. Criteria for the removal of samples and probes can be found in Zillich et al. [15]. In the present analyses, DNA methylation data were included from all subjects from whom gene expression data were available after QC.
