"Biological age (BA) has been proposed to evaluate the aging status instead of chronological age (CA). Our study shows evidence that there might be multiple “clocks” within the whole-body system: systemic aging drivers/clocks overlaid with organ/tissue-specific counterparts. We utilize multi-omics data, including clinical tests, immune repertoire, targeted metabolomic molecules, gut microbiomes, physical fitness examinations, and facial skin examinations, to estimate the BA of different organs (e.g., liver, kidney) and systems (immune and metabolic system). The aging rates of organs/systems are diverse. People’s aging patterns are different. We also demonstrate several applications of organs/systems BA in two independent datasets. Mortality predictions are compared among organs' BA in the dataset of the United States National Health and Nutrition Examination Survey. Polygenic risk score of BAs constructed in the Chinese Longitudinal Healthy Longevity Survey cohort can predict the possibility of becoming centenarian."
"Our approaches to estimating BAs for organs and systems could be easily used in clinical practice or health management for elderly people. It is noteworthy that the biomarkers we used for constructing BAs were mostly gained from routine physical checkups or blood sample tests, which are easy to scale up for health management of larger populations."
"Klemera and Doudal algorithm (Klemera and Doubal, 2006) was used for the construction of biological ages. Briefly, the KD method was consisted of two steps to convert those biomarkers into aging rate and making them comparable. The first step is regressing every biomarker to chronological age. By doing this, we gained the estimated age as well as its standard error using a particular biomarker. Every biomarker was processed and all the estimated ages have the unit ‘year’ which is the same as chronological age. We consider the regression step as a normalization process that make different markers comparable in terms of unit. The second step is aggregating the age estimates of each biomarker as well as chronological age and construct biological ages."
Nie C, Li Y, Li R, Yan Y, Zhang D, Li T, Li Z, Sun Y, Zhen H, Ding J, Wan Z, Gong J, Shi Y, Huang Z, Wu Y, Cai K, Zong Y, Wang Z, Wang R, Jian M, Jin X, Wang J, Yang H, Han JJ, Zhang X, Franceschi C, Kennedy BK, Xu X. Distinct biological ages of organs and systems identified from a multi-omics study. Cell Rep. 2022 Mar 8;38(10):110459. doi: 10.1016/j.celrep.2022.110459. PMID: 35263580.
https://www.cell.com...47(22)00186-3#