Cross-sectional evaluation of potential biological markers of aging in pigtailed macaques: effects of age, sex, and diet.

The objective of our research was to establish a useful battery of innocuous tests suitable for detecting individual differences in biological aging rate in pigtailed macaques. Data were gathered from more than 60 animals of three age groups (8 to 9, 12 to 17, and 18 to 28 years olds) fed two diets differing in lipid, cholesterol, complex carbohydrate, refined sugar, and sodium chloride content. Candidate variables for an aging battery were identified in a cross-sectional analysis by performing a three-way analysis of variance (ANOVA) for the effects of age, sex, and diet on each of 72 variables. Twenty-eight variables were found to be influenced by age. By examining patterns of differences among means, 20 variables were identified that show promise of being useful, including, for example, rectal body temperature, blood albumin, immunoglobulin A, fingernail growth rate, bone thickness, and blood calcium. The set of variables used to estimate biological aging might not be identical for all age-sex classes.