Ischemic stroke is associated with aging. It is possible to predict chronological age by measuring age-related changes in DNA methylation from multiple CpG sites across the genome, known as biological age. The difference between biological age and actual chronological age would indicate an individual's level of aging. Our aim was to determine the biological age of ischemic stroke patients and compare their aging with controls of the same chronological age. A total of 123 individuals, 41 controls and 82 patients with ischemic stroke were paired by chronological age, ranging from 39 to 82 years. Illumina HumanMethylation450 BeadChip array was used to measure DNA methylation in CpG sites in both groups, and biological age was estimated using methylation values of specific CpGs. Ischemic stroke patients were biologically an average 2.5 years older than healthy controls (p-value=0.010). Stratified by age tertiles, younger stroke patients (≤57 years old) were biologically older than controls (OR=1.19; 95%CI 1.00-1.41, p-value=0.046). The older groups showed no biological age differences between cases and controls, but were close to reaching the significance level. Ischemic stroke patients are biologically older than controls. Biological age should be considered as a potential new biomarker of stroke risk.

This project was funded in part by the following sources: Agència de Gestió Ajuts Universitaris de Recerca (2014 SGR 1213); Spain’s Ministry of Health (Ministerio de Sanidad y Consumo) through the Carlos III Health Institute (ISCIII-FIS-FEDER-ERDF, PI12/01238, PI15/00451, PI15/00445); the Red de Investigacion Cardiovascular, Instituto de Salud Carlos III RETIC (RD12/0042/0020, RD12/0042/0013); and a RecerCaixa 2013 research grant (JJ086116). S.S-B. is funded by an iPFIS contract from Instituto de Salud Carlos III (IFI14/00007).