Understanding the processes and determinants of healthy ageing is important, not merely because we all want to live longer, but because we want our years to be active and healthy. With declining fertility and increasing life expectancy, populations in Europe and elsewhere are ageing rapidly, and at an increasing pace, making it more urgent to understand how to ensure healthy ageing. Ageing is a dynamic process that is highly variable and affected by many determinants. It is convenient to speak of ‘health trajectories’ in order to capture this variation. A health trajectory is a pathway from birth to death defined in terms of length of life (longevity) and health status (the extent of morbidity, disability, or less than optimal health, experienced at a point in time). ATHLOS’ objective is to achieve a better understanding of ageing by identifying patterns of healthy ageing trajectories, the determinants of those patterns, the critical points in time when changes in trajectories are produced, and to propose timely clinical and public health interventions to optimise healthy ageing. Moreover, a new definition of ‘old age’ including not only chronological age but also health status to define an aged person will be used for calculating projections in specific population groups, and guide policy recommendations. To do so, ATHLOS has created a harmonised dataset with over 400,000 individuals collated from existing longitudinal studies of ageing and including information on physical and mental health, life style habits, social environment, and participation, among others. A Healthy Ageing Scale will be developed using Item Response Theory methods with individual items from the surveys. Diverse complex statistical models will be employed to define health trajectories. Specific interventions both at clinical and population level will be designed based on ATHLOS. The impact of these interventions on healthy ageing will be assessed with micro-simulation methods. Stakeholders will participate in the definition of outcomes, the creation of interventions, and dissemination of results. ATHLOS will make its resources available to scientists and stakeholders by providing access to the methodology of harmonisation and to the mega dataset of ageing cohorts. To maximise the policy impact, target audiences will be identified and specific materials disseminated.
