You are here

Much Like the Rings of a Tree, Bones Reveal Biological Age in Humans

Researchers at the Research and Training Institute at Hebrew Rehabilitation Center for Aged have been studying bones to assess the impact of genes versus the environment on how an individual ages. In an article published recently in the Journal of Gerontology: Biological Sciences, lead author David Karasik, Ph.D., and colleagues describe how bones can reveal an individual’s biological age and how they used this information to conclude that genes seem to trump environmental factors when it comes to the aging process.

The quest to understand how people age, and why some people fare so much better in the process than others, has garnered much interest lately as the percentage of the population over 65 continues to swell worldwide. As a result, developing reliable means to measure the variability in human aging has become an important part of clinical gerontological research. Biological age refers to how healthy an individual is compared to the average individual of the same chronological age.

According to Dr. Karasik’s paper, age-related bone loss seems to reflect a general breakdown in body tissue observable elsewhere in the aging body, and can therefore serve as a model for human aging, providing insight into basic biological changes that occur with age.

Just as the number of growth rings in a tree increase with time, revealing its age, degenerative changes in human bone also accumulate as an individual grows older. Dr. Karasik is able to measure these changes by observing hand radiographs. Using a scoring system referred to as an Osseographic Scoring System (OSS) he is able to determine an individual’s biological age.

Institute researchers evaluated a study sample of 1402 participants in the Framingham Heart Study, which has followed subjects over two generations. Once the researchers had determined the biological ages of the study participants, the search was on for a genetic connection. Recent advances in molecular genetics and genetic epidemiology have allowed other scientists to identify chromosomal regions that affect age-related diseases like diabetes, Alzheimer’s disease and osteoporosis. The evaluations showed that in the majority of cases genes influenced the variance in biological age.

The results of this research have important implications in terms of evaluating an individual’s aging status and predicting risk for age-related diseases. A hand radiograph may serve as an indicator of an individual’s biologic age and his or her genetic susceptibility to age-related disease. This information could help an individual early on make health care and lifestyle choices to optimize health with age.