Relationship Between Frailty And Executive Function By Age And Sex In The Canadian Longitudinal Study Of Aging

Frailty reflects age-related damage to multiple physiological systems. Executive dysfunction is often a presenting symptom of diseases characterized by cognitive impairment. Worsened cardiovascular health is also associated with worsened executive function. PURPOSE: To test the hypothesis that higher frailty would be associated with executive dysfunction and that cardiovascular function would mediate this relationship. METHODS: Middle-aged and older-aged adults at baseline (n = 29,591 [ 51% female]) and 3-year follow-up (n = 25,488 [12911 females]) from the Canadian Longitudinal Study of Aging were included. Frailty at baseline was determined from a 61-item index, a cumulative cardiovascular score was calculated from 30 cardiovascular health variables (ratio), and participants completed a word-colour Stroop task as a measure of executive function. Multiple linear regressions and mediation analyses (mediator: cardiovascular score) were conducted between frailty, Stroop reaction time and cardiovascular function in groups stratified by both age and sex (middle-aged males [MM], middle-aged females [MF], older-aged males [OM], older-aged females [OF]). RESULTS: Frailty (MM:0.15 ± 0.05, MF:0.16 ± 0.06, OM:0.21 ± 0.06, OF:0.23 ± 0.06) was associated with both cardiovascular health (MM:0.12 ± 0.1, MF:0.11 ± 0.1, OM:0.20 ± 0.1, OF:0.18 ± 0.1; β > 0.037, p < 0.001) and Interference condition reaction time (MM:23.7 ± 7.9 s, MF:23.1 ± 7.3 s, OM:32.9 ± 13.1 s, OF:30.9 ± 12.0 s; β > 2.57, p < 0.001) across all groups when adjusted for covariates. Cardiovascular health was a partial (~10%) mediator between frailty and reaction time across all groups, aside from middle-aged females. CONCLUSIONS: Higher frailty levels are associated with executive dysfunction, which are partially mediated by worse cardiovascular health. Strategies to improve frailty and better cardiovascular health may be useful for combatting the age-related decline in executive function.