Epigenetic clocks, commonly used to measure biological age, have primarily been trained using blood samples. However, there is a growing interest in using oral-based tissues for estimating epigenetic age. The unique DNA methylation landscapes and age-related alterations in different cell types across body tissues can introduce biases when applying blood-derived epigenetic clocks to oral-based tissues.
A study tested the comparability of epigenetic clocks across five tissue types and found significant differences in age estimates between oral-based and blood-based tissues, with discrepancies of almost 30 years in some cases. Despite controlling for technical factors, most epigenetic clock estimates did not correlate well between blood-based and oral-based tissues.
These findings suggest that using blood-derived epigenetic clocks in oral-based tissues may not provide accurate estimates of epigenetic age. Researchers need to carefully consider tissue type when estimating biological age using epigenetic clocks.
