Comparison of visually estimated age with physiologically predicted age as indicators of rates of aging

The commonly held view that people age at different rates derives largely from visual estimates of age. Although most people 'look their age' everyone can cite examples of individuals in middle and late adulthood who appear to be aging very slowly or very rapidly. Efforts to quantify aging rates scientifically require measurement of a large number of physiological parameters in a large population sample. This paper compares visual estimates of age with physiologically predicted measures to determine their value as indicators of the rate of aging. This study used data from 1086 male participants in the Baltimore Longitudinal Study of the Gerontology Research Center, NIA. These men have provided comprehensive biomedical and psychosocial data at one and one-half year intervals for as long as 20 years. The visual estimate of age was made by the examining physician at the first study visit of each participant, without knowledge of the man's actual age. The error of this estimate was determined by subtracting actual age from estimated age. Correlation analysis of error in estimated age with an objective assessment of biological age based on physiological variables indicated a significant association between the two approaches. When men who have died since their study participation were compared with survivors, the former were found to have been significantly 'older for their age' than the latter using both visual and physiological estimate approaches. To determine whether certain lifestyle traits were associated with variation in these two indicators, multiple regression analyses were performed. These showed that men who smoked, who are fatter, or who were in poor health were predicted as older than their chronological age peers using both approaches. Results of this study suggest that the easily determined visual estimate of age may be a useful indicator of aging rate within a population.