DNAm was profiled in DNA extracted from whole blood for 1,193 individuals who were aged from 28 to 98; who were eligible for and consented to both blood sampling and genetic analysis; who had been present at all annual interviews between 1999 and 2011; and whose time between blood sample collection and processing did not exceed 3 days. Eligibility requirements for genetic analyses meant that the epigenetic sample was restricted to participants of white ethnicity. The EZ-96 DNA Methylation-Gold kit (Zymo Research) was used for treating 500 ng of DNA from each sample with sodium bisulfite. DNAm was quantified with the Illumina Infinium HumanMethylationEPIC BeadChip run on an Illumina iScan System according to the manufacturer’s standard protocol. Samples were randomly assigned to chips and plates so that batch effects would be minimized. In addition, the inclusion of a fully methylated control (CpG Methylated HeLa Genomic DNA; New England BioLabs) in a random position on each plate facilitated sample tracking and helped to resolve experimental inconsistencies and confirm data quality.