A study on the basic nature of human biological aging processes based upon a hierarchical factor solution of the...

The purpose of this study is to determine the laws governing the aging processes based on a hierarchical factor solution of the age-related physiological variables. Healthy individuals (462) who had taken a 2-day health examination were studied. Twenty-seven physiological variables were submitted to hierarchical factor solution. The analysis revealed that there was a fixed pattern in the variations of these 27 physiological variables. In this hierarchical factor solution, three group factors as functioning at different levels of complexity composed of the 16 common factors were extracted. Of these group factors, the first and third group factors can be referred to the aging process. The first group factor, the so-called factor 1 loaded with most of physiological variables, was interpreted as a primary aging factor which presented the primary process of human aging. The third group factor, the so-called factor 6 to 16 loaded only with a few variables related to a single physiological system or organ, were interpreted as system-specific secondary aging factor. These results obtained by the hierarchical factor solution thus seem to support the notion that biological age changes can be viewed as time dependent complex integration of the primary and secondary aging processes.