@article {12565, title = {Development of a common scale for measuring healthy ageing across the world: results from the ATHLOS consortium.}, journal = {International Journal of Epidemiology}, volume = {50}, year = {2021}, pages = {880-892}, abstract = {

BACKGROUND: Research efforts to measure the concept of healthy ageing have been diverse and limited to specific populations. This diversity limits the potential to compare healthy ageing across countries and/or populations. In this study, we developed a novel measurement scale of healthy ageing using worldwide cohorts.

METHODS: In the Ageing Trajectories of Health-Longitudinal Opportunities and Synergies (ATHLOS) project, data from 16 international cohorts were harmonized. Using ATHLOS data, an item response theory (IRT) model was used to develop a scale with 41 items related to health and functioning. Measurement heterogeneity due to intra-dataset specificities was detected, applying differential item functioning via a logistic regression framework. The model accounted for specificities in model parameters by introducing cohort-specific parameters that rescaled scores to the main scale, using an equating procedure. Final scores were estimated for all individuals and converted to T-scores with a mean of 50 and a standard deviation of 10.

RESULTS: A common scale was created for 343~915 individuals above 18 years of age from 16 studies. The scale showed solid evidence of concurrent validity regarding various sociodemographic, life and health factors, and convergent validity with healthy life expectancy (r = 0.81) and gross domestic product (r = 0.58). Survival curves showed that the scale could also be predictive of mortality.

CONCLUSIONS: The ATHLOS scale, due to its reliability and global representativeness, has the potential to contribute to worldwide research on healthy ageing.

}, keywords = {Aging, Cohort Studies, Health Status, healthy aging, Humans, Reproducibility of Results}, issn = {1464-3685}, doi = {10.1093/ije/dyaa236}, author = {Sanchez-Niubo, Albert and Forero, Carlos G and Wu, Yu-Tzu and Gin{\'e}-V{\'a}zquez, Iago and Prina, Matthew and de la Fuente, Javier and Daskalopoulou, Christina and Critselis, Elena and De La Torre-Luque, Alejandro and Panagiotakos, Demosthenes and Arndt, Holger and Ayuso-Mateos, Jos{\'e} Luis and Bayes-Marin, Ivet and Bickenbach, Jerome and Bobak, Martin and Caballero, Francisco F{\'e}lix and Chatterji, Somnath and Egea-Cort{\'e}s, Laia and Garc{\'\i}a-Esquinas, Esther and Leonardi, Matilde and Koskinen, Seppo and Koupil, Ilona and Mellor-Mars{\'a}, Blanca and Olaya, Beatriz and Paj{\k a}k, Andrzej and Prince, Martin and Raggi, Alberto and Rodr{\'\i}guez-Artalejo, Fernando and Sanderson, Warren and Scherbov, Sergei and Tamosiunas, Abdonas and Tobias-Adamczyk, Beata and Tyrovolas, Stefanos and Haro, Josep Maria} }