Trajectories of physical function decline and psychological functioning: the Quebec longitudinal study on nutrition and successful aging (NuAge).

BACKGROUND Decline of physical function with age is associated with substantial health consequences. Physical and psychological functioning is linked, but the temporal nature of this association remains unclear. METHODS Three-year follow-up data from men and women (n = 1,741), aged 68-82 years, in the longitudinal study on nutrition and successful aging (NuAge; Québec, Canada) were used. Growth curve modeling was performed to examine trajectories of a global physical performance score across time as conditioned by cognition and depression. RESULTS Significant decline in physical function was observed (p < .0001). Rate of decline in physical performance score was accelerated in the older participants (>77 years; age(2): p < .01) but not affected by slight decline in cognition or depression. Yet, people with lower cognition level and more depressive symptoms show lower physical capacity throughout the entire follow-up period (p < .0001). CONCLUSIONS Physical function significantly declined over 3 years, in particular in the oldest group. A subtle decline in psychological health paralleled decline in physical function but did not accelerate it.