Scientists use animal models to answer a variety of scientific questions about humans, from basic science to the pathophysiology of complex diseases. The reliability of these models is based on remarkable similarities in the biology of most mammals and the fact that many human diseases often affect other animal species. Findings from a recent study suggest that glucose homeostasis in aging differs between some commonly studied animals and humans.

As humans age, they experience significant changes in glucose metabolism and body composition. For example, insulin resistance is common among older adults, increasing their risk for type 2 diabetes. In addition, a person’s fat mass typically increases and muscle mass and bone mineral density decrease.

The authors of the study compared the trajectories, change rates, and death rates associated with fasting blood glucose, body weight, and fat mass in mice, nonhuman primates, and humans across their lifespans. They drew on data from the Study of Longitudinal Aging in Mice, the Nonhuman Primate Study, and the Baltimore Longitudinal Study of Aging.

They found that body weight and body fat across the three species followed similar trajectories, typically peaking in mid to late life and decreasing thereafter. However, fasting blood glucose levels decreased as the mice aged but increased as the nonhuman primates and humans aged. Having low glucose in mice and high glucose in nonhuman primates and humans translated to higher death rates.

These findings suggest that aging-related changes in glucose homeostasis differ among species and underscore the need for choosing appropriate animal models in aging research.

• Link to study abstract.