Evaluation of epigenetic age acceleration scores and their associations with CVD related phenotypes in a population cohort

Background Epigenetic age acceleration (EAA) is a measure that can be used to investigate the relationship between molecular, clinical and phenotypic data. However, which EAA score is best suited for which phenotype(s) is an open question. To address this issue, we have conducted a comprehensive comparison of multiple EAA scores using currently understudied Eastern European ageing population cohort (HAPIEE) which is richly annotated for diverse phenotypes. Our analysis was based on a subset (n = 306; aged between 45 and 69 years) of samples with available DNA methylation (DNAm) and phenotypic data. Results We calculated nine established EAA measures and performed statistical hypothesis testing to investigate associations between these scores and 18 cardiometabolic phenotypes. This was implemented by splitting the data into groups with positive and negative EAAs. We observed strong association between all EAA scores and sex, suggesting that in any analysis EAAs should be adjusted by sex. We found that some sex-adjusted EAA scores were significantly associated with several phenotypes (not necessarily the same phenotypes for different EAAs), indicating that some EAA scores are more phenotype-specific than others. We were able to replicate some of the associations in sex-specific subsets. Furthermore, the most of the EAA associations with cardio-vascular (except presence of Carotid Plaque (CP)) and lipids phenotypes were established in females but not males (and vice versa for CP and alcohol intake). This demonstrates that even after adjusting EAAs for sex, EAA-phenotype associations remain sex-specific, which should be taken into account in any downstream analysis involving EAAs. We observed that in some EAA-phenotype associations, negative EAA scores (i.e. epigenetic age below chronological age) indicated more harmful phenotype values, which is counter-intuitive. Overall, GrimAge was associated with more phenotypes than any of the other EAA scores. Conclusions EAAs are sex-specific and should be adjusted for sex in EAA-phenotypes association studies. Associations between EAAs and cardiometabolic phenotypes are sex-specific, even after adjusting for sex. For some EAAs, the direction of the association with phenotype is counter-intuitive. Our results can be used as a guidance on which EAA score to use for which phenotype(s). ### Competing Interest Statement The authors have declared no competing interest. * ACS : Acute coronary syndrome adjEAA : Adjusted epigenetic age acceleration ASE : American Society of Echocardiography BMI : Body mass index BP : Blood pressure CA : Chronological age CARDIA : Coronary Artery Risk Development in Young Adults CHD : Coronary heart disease CP : Carotid plaque CpG : Cytosine-phospate-guanine CVD : Cardio-vascular disease DBP : Diastolic blood pressure DNAm : DNA methylation EA : Epigenetic age EAA : Epigenetic age acceleration EASD : European Association for the Study of Diabetes EEAA : Extrinsic epigenetic age acceleration EGA : European Genome-phenome Archive ESC : European Society of Cardiology ESH : European Society of Hypertension FPG : Fasting plasma glucose GENOA : Genetic Epidemiology Network of Arteriopathy GGT : Gamma-glutamyl transferase HAPIEE : Health, Alcohol, and Psychosocial Factors in Eastern Europe HDL : High-density lipoprotein HT : Hypertension IEAA : Intrinsic epigenetic age acceleration IIPM : Institute of Internal and Preventive Medicine LDL : Low-density lipoprotein MCP : Multiple carotid plaques MI : Myocardial infarction QC : Quality control SBP : Systolic blood pressure T2DM : Type 2 diabetes mellitus TC : Total cholesterol TG : Triglycerides WHR : Waist-hip ratio