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.