Key points from article :
Blood permeates all other organs and thus reflects the state of the whole organism.
Drawing blood requires an appointment with a clinic.
Saliva is a much easier tissue to collect, as it can be done at home and non-invasively.
Last year Deep Longevity released an accurate epigenetic aging clock – DeepMAge - which used with blood samples.
Blood-trained model can be repurposed for saliva samples with practically no drop in performance.
DeepMAge initially had 20.9 years of error with saliva, but the new adjustment restored its accuracy to 4.7 years.
Heterogeneity of saliva samples consist of variable proportions of epithelial and immune cells.
These cell types age at a different speed, obfuscating the organismal age.
Cell-type deconvolution method EpiDISH salvages its performance.
Research led by Alex Zhavoronkov published in Frontiers in Aging.