Dynamic associations between frailty and cognition over 4 years: A population-based study on adults aged ≥50 from 12 European countries

This study aimed (1) to investigate autoregressive and cross-lagged associations between frailty and cognition over 4 years in a large sample of European citizens aged ≥50 years, (2) to examine the 4-year temporal associations' differences between sex and between active and inactive physical behaviour, and (3) to explore in the years 2011, 2013, and 2015 associations between cognitive performance and the pre-frailty and frailty conditions. This longitudinal analysis was conducted with 20,857 individuals (11,540 women) from 12 countries aged ≥50 years who responded to waves 4, 5, and 6 of the SHARE project. The variables analysed were frailty (SHARE-FI) and a general cognition index (Cogindex) calculated for each wave from verbal fluency, immediate recall, and delayed recall. A greater propensity for cognitive impairment was found in women, as well as in pre-frail and frail individuals. There were no significant differences between the sexes for the autoregressive effect of frailty and Cogindex over 4 years. On the other hand, sedentary and active individuals differed in frailty between Time 1–2. Cross-lagged analyses indicated a significant difference for the sexes between frailty and Cogindex Time 1–3 and between Cogindex and frailty of Time 2–3. Sedentary and active differed significantly in the path of frailty on Cogindex between Time 2–3. Health policies should increase surveillance of frailty, cognition, and level of physical activity in the older European population, with a special focus on women.