Construction Formula of Biological Age Using the Principal Component Analysis

Abstract

The biological age (BA) equation is a prediction model that utilizes an algorithm to combine various biological markers of ageing. Different from traditional concepts, the BA equation does not emphasize the importance of a golden index but focuses on using indices of vital organs to represent the senescence of whole body. This model has been used to assess the ageing process in a more precise way and may predict possible diseases better as compared with the chronological age (CA). The principal component analysis (PCA) is applied as one of the common and frequently used methods in the construction of the BA formula. Compared with other methods, PCA has its own study procedures and features. Herein we summarize the up-to-date knowledge about the BA formula construction and discuss the influential factors, so as to give an overview of BA estimate by PCA, including composition of samples, choices of test items, and selection of ageing biomarkers. We also discussed the advantages and disadvantages of PCA with reference to the construction mechanism, accuracy, and practicability of several common methods in the construction of the BA formula.

Common methods of biological age estimation

“…The PCA approach uses fewer uncorrelated variables to explain the optimizing variance, and this method avoids some of the statistical deficiencies of MLR, such as distortion at the regression edge and discontinuity of the aging rate over the lifespan 20. However, PCA is still based on linear regression.…”

“…Due to the easy operation and superiority to MLR, PCA is used by researchers with limited computer technology and statistical capacity. In our recent review, we have introduced in detail the criteria of subjects, biomarker selection, basic steps, and some other important points of BA estimation using PCA 20. We also summarized the aging biomarkers selected in the previous researches and explained about the genetic factors as a reference for future studies 20…”

“…Every researcher should choose the most suitable approach according to the subjects, research conditions, funds, statistical methods, and even computer skills. MLR is the simplest method that can detect the stabilization and multi-collinearity of empirical data 16,20. However, the edge distortion and paradox of CA cannot be avoided in MLR 22,60.…”

Biological age is a universal marker of aging, stress, and frailty

“…The method is an almost always the first choice in biological data analysis and searches for aging signatures in a multitude of biological signals ranging from blood samples to locomotor activity patterns (Pyrkov et al 2018b), anthropological and functional measures (Park et al 2009), and microbiome composition (Odamaki et al 2016). In most cases only a few, most often the first, PCA scores were associated with age and hence could be naturally interpreted as biomarkers of age Miyao 2007, Nakamura et al 1988), see Jia et al (2016) for a recent review and references therein.…”

Is Donated Breast Milk Better Than Formula for Feeding Very Low Birth Weight Infants? A Systematic Review and Meta‐Analysis

“…The disinfection process of donated breast milk may affect its nutritional value and immune components and are therefore many ways in which breast milk is donated informally in name of “sharing” with potential risks; its clinical application effect is also questioned in this way (ESPGHAN Committee on Nutrition et al, ; Gaya & Calvo, ). While for formula, its ingredients and related proportion may exert great influence on the prognosis of infants (Jia et al, ; Kent, ), it is still necessary to further address the role of donated breast milk and formula use in feeding infants.…”