Objectives: Intact cognition is a key determinant of quality of life. Here, we investigated the relative contribution of age and physical frailty to global and everyday cognition in older adults.
Methods: Data came from 1396 community-dwelling, healthy Chinese older adults aged 65 or above. We measured their global cognition using the Cantonese Chinese Montreal Cognitive Assessment, everyday cognition with the short Chinese Lawton Instrumental Activities Daily Living scale, and physical frailty using the Fatigue, Resistance, Ambulation, Illness, and Loss of Weight Scale and grip strength. Multiple regression analysis was used to evaluate the comparative roles of age and physical frailty.
Results: In the global cognition model, age explained 12% and physical frailty explained 8% of the unique variance. This pattern was only evident in women, while the reverse (physical frailty explains a greater extent of variance) was evident in men. In the everyday cognition model, physical frailty explained 18% and chronological age explained 9% of the unique variance, with similar results across both genders.
Conclusion: Physical frailty is a stronger indicator than age for everyday cognition in both genders and for global cognition in men. Our findings suggest that there are alternative indexes of cognitive aging than chronological age.
Keywords: Chronological age; everyday cognitive function; gender difference; global cognitive function; physical frailty.