A recent study published in Genome Biology examined blood, saliva and brain samples from various racial groups and genders to compare extrinsic and intrinsic epigenetic aging. As you might expect, results indicated both gender and race impact aging.
According to the article abstract, epigenetic biomarkers of aging have the potential to address questions surrounding mortality rates and incidences of cardio-metabolic disease. For example, why do women consistently exhibit lower mortality than men despite higher levels of morbidity? And why do racial/ethnic groups have different mortality rates even after adjusting for socioeconomic differences?
In blood, these researchers assessed both the intrinsic epigenetic age acceleration and the extrinsic epigenetic aging rates. They found that Hispanics and Tsimane Amerindians have lower intrinsic, but higher extrinsic epigenetic aging rates than Caucasians. Also, African-Americans have lower extrinsic epigenetic aging rates than Caucasians and Hispanics, but no differences were found for the intrinsic measurement.
Furthermore, men have higher epigenetic aging rates than women in blood, saliva and brain tissue. The authors concluded epigenetic aging rates are significantly associated with gender, race/ethnicity, and to a lesser extent with congenital heart defect (CHD) risk factors.
How was this measured? According to the paper, recent studies have measured the epigenetic age of tissue samples by combining the DNA methylation levels of multiple dinucleotide markers, known as Cytosine phosphate Guanines (CpGs). The researchers developed an epigenetic clock based on 353 CpGs to measure the age, known as "DNA methylation age” or “epigenetic age,” of assorted human cell types (CD4+ T cells or neurons), tissues and organs, and even prenatal brain samples. The epigenetic clock is an interesting biomarker of aging because it applies to most human tissues, and its accurate measurement of chronological age is unprecedented.
While the purpose of this study was to help elucidate lower than expected mortality rates observed in Hispanics, older African-Americans and women, it could have implications in personal care, insofar as how epigenetics might be targeted for anti-aging benefits.