Longitudinal studies: contributions to addressing the challenges of ageing

An ageing population poses challenges in ensuring the well-being of this demographic and requires changes to social and health policies, long-term care and housing environments, amongst other areas. To address these challenges, it is necessary to generate rigorous evidence, and longitudinal studies are essential for this purpose.

Only a population-based study with a longitudinal design allows us to examine the process and determinants of healthy ageing, taking into account the demographic and social changes that will take place over the next decade. A longitudinal study is a research design that involves studying the same individuals over an extended period of time. This type of study provides more accurate indicators of changes across generations and allows for clearer conclusions to be drawn about the ageing process, thereby enabling evidence-based decision-making. Among the opportunities offered by a longitudinal study are: the possibility of analysing the individual and collective ageing process and understanding the differences between different groups; incorporating internationally comparable research models; exploring causalities, determinants and consequences, as well as gender differences; and identifying future trends regarding longevity and long-term care.

This Summer Course, organised by the Basque Government’s Department of Wellbeing, Youth and Demographic Challenge in collaboration with the Matia Institute, presents “Bizaria”, the longitudinal study on longevity and care in the Basque Country, which completed its first wave in 2025. Building on this experience, the course will analyse how longitudinal studies generate evidence to inform the design of ageing policies, and will share established international experiences such as LASA (Netherlands), SNAC-K (Sweden) and ELSA (United Kingdom), exploring the methodological and organisational challenges involved in their development and continuity over time, as well as the impact they have had on their respective societies.

Objectives:

• To present the “Bizaria” study, its methodological design, the results of the first wave carried out in 2025, and the prospects for the continuation of the longitudinal study on longevity and care in the Basque Country.
• To understand how longitudinal studies generate scientific evidence that underpins the design of social and health policies aimed at healthy ageing.
• To examine established international experiences (LASA, SNAC-K, ELSA) in conducting longitudinal studies on ageing, analysing their methodological contributions, organisational challenges and the impact they have had on their respective societies.