Usefulness of stochastic analysis of body weight as a tool in experimental aging research

The statistical characteristics of body weight in a number of longitudinally studied mouse populations were examined. Frequency distribution of body weights appears to be rather "fluid" (though within a strict range), changing from symmetric to positively skewed to symmetric and finally to negatively skewed as the mice pass through the stages of early maturity, middle age, and senescence. Because body weight is a highly integrated physiological variable, it is postulated that various diets which affect survivorship would affect body weight frequency distribution similarly. The data from studies with an antioxidant diet and two toxic diets support this hypothesis. In general, the effects on body weight can be assessed in a relatively short time (6-9 months) after initiation of the experiment and 4-6 months before the effect of the experimental diet is manifested in the population's survivorship, thus offering an analytical tool for considerable shortening of the duration of such studies.