Table 1 Overview of various measures of epigenetic age acceleration and mortality risk used in this analysis
Epigenetic marker | Abbreviation | CpGs | Description | References |
|---|---|---|---|---|
Intrinsic Epigenetic age acceleration based on Horvath | IEAA | 353 | The residual resulting from regressing DNAm age on chronological age and estimates of major blood immune cell counts * | [26] |
Intrinsic epigenetic age acceleration based on Hannum | IEAAHannum | 71 | [27] | |
Extrinsic age acceleration based on Hannum | EEAA | 71 | The residual resulting from a univariate model regressing a weighted age estimate (which increases the contribution of 3 cell types known to change with age **) on chronological age | [21] |
Age acceleration based on PhenoAge | AgeAccelPheno | 513 | The residual resulting from a linear model when regressing PhenoAgeAccel on chronological age, where PhenoAge is an ageing measure based on a linear combination of chronological age and nine clinical biomarkers | [34] |
Age acceleration based on GrimAge | AgeAccelGrim | 1030 | The residual resulting from a linear model when regressing GrimAge on chronological age, where GrimAge is an ageing measure based on a linear combination of chronological age, sex and DNAm-based surrogate biomarkers for smoking pack-years (DNAmpackyears) and seven plasma protein levels | [35] |
Mortality risk score based on Zhang | ZhangScore | 8 | A linear combination of LASSO regression coefficient weighted methylation values of the ten CpGs | [36] |