Mathematical modeling of fitness and frailty in relation to biological age in individuals and populations

Chronological age is often used as a rough measure of the aging process. But individuals do not die from old age. They die because they become more vulnerable, and this occurs with age. We have developed a better measure of aging than chronological age - a measure that takes individual health vulnerability into account. This 'frailty index' represents a person's biological age by integrating various characteristics of health and social-demographics. The frailty index is used to predict individuals' future health status and their risk of adverse outcomes (the chance of entering a nursing home or of dying). Because the frailty index summarizes health status as a single number, we can analyze the trajectories of how individual people's health changes over time. This has the potential to open up exciting opportunities, such as to describe the conditions under which biological aging (deficit accumulation) might become slower. In this project, we seek to further develop our modeling technique to analyze individual trajectories of changes, and to identify the factors influencing these changes. We aim to apply an advanced analytical technique to detecting such factors, even when their influence is seemingly small. Even small changes in individual's chances of health improvement may result in a considerable improvement in population health. We will conduct these studies using large databases of health data from Canada and other countries, on tens of thousands individuals followed for up to 20 years. This gives us the resources to validate novel techniques that are sensitive to small but important factors, including biological, social, environmental characteristics and lifestyle variables. In addition, we aim to make our research findings useful for clinical practice, to help improve health care for older people. Our multidisciplinary team will provide a good account of not only how health changes occur in older adult but at what extent the process of changes can be reversed.