DNA methylation age (DNA methylation-based age) predicts all-cause mortality in later life. This study tested whether the difference between chronological age and DNA methylation age (Δage) predicts mortality. Δage was calculated in four longitudinal cohorts of older individuals. Meta-analysis of proportional hazards models from the four cohorts showed that a 5-year higher Δage was associated with a 21% higher mortality risk, adjusting for age and sex. After further adjustments for childhood IQ, education, social class, hypertension, diabetes, cardiovascular disease, and APOE e4 status, a 5-year higher Δage was associated with a 16% increased mortality risk. A pedigree-based heritability analysis showed that Δage had a heritability of 0.43. The study concluded that DNA methylation-derived measures of accelerated aging are heritable traits that predict mortality independently of health status, lifestyle factors, and known genetic factors. The study also found that Δage was associated with mortality in four independent cohorts of older individuals, independent of life-course predictors of aging and death such as APOE e4 allele, education, childhood IQ, social class, diabetes, high blood pressure, and cardiovascular disease. The study used two distinct epigenetic biomarkers of aging (Δage) one from DNA methylation in whole blood, and one based on results across multiple tissues. The associations between Δage and mortality were stronger for the blood-based predictor but the two measures became comparable after adjusting for naive CD8 T cell abundances. The study also found that Δage was associated with mortality in four independent cohorts of older individuals, independent of life-course predictors of aging and death such as APOE e4 allele, education, childhood IQ, social class, diabetes, high blood pressure, and cardiovascular disease. The study concluded that DNA methylation-derived measures of accelerated aging are heritable traits that predict mortality independently of health status, lifestyle factors, and known genetic factors.DNA methylation age (DNA methylation-based age) predicts all-cause mortality in later life. This study tested whether the difference between chronological age and DNA methylation age (Δage) predicts mortality. Δage was calculated in four longitudinal cohorts of older individuals. Meta-analysis of proportional hazards models from the four cohorts showed that a 5-year higher Δage was associated with a 21% higher mortality risk, adjusting for age and sex. After further adjustments for childhood IQ, education, social class, hypertension, diabetes, cardiovascular disease, and APOE e4 status, a 5-year higher Δage was associated with a 16% increased mortality risk. A pedigree-based heritability analysis showed that Δage had a heritability of 0.43. The study concluded that DNA methylation-derived measures of accelerated aging are heritable traits that predict mortality independently of health status, lifestyle factors, and known genetic factors. The study also found that Δage was associated with mortality in four independent cohorts of older individuals, independent of life-course predictors of aging and death such as APOE e4 allele, education, childhood IQ, social class, diabetes, high blood pressure, and cardiovascular disease. The study used two distinct epigenetic biomarkers of aging (Δage) one from DNA methylation in whole blood, and one based on results across multiple tissues. The associations between Δage and mortality were stronger for the blood-based predictor but the two measures became comparable after adjusting for naive CD8 T cell abundances. The study also found that Δage was associated with mortality in four independent cohorts of older individuals, independent of life-course predictors of aging and death such as APOE e4 allele, education, childhood IQ, social class, diabetes, high blood pressure, and cardiovascular disease. The study concluded that DNA methylation-derived measures of accelerated aging are heritable traits that predict mortality independently of health status, lifestyle factors, and known genetic factors.