Everyday Cognitive Functioning and Global Cognitive Performance are Differentially Associated with Physical Frailty and Chronological Age in Older Chinese Men and Women

Abstract

Objectives: Intact cognition is a key determinant of independence and quality of life in old age. Here, we investigated the relative contribution of age and physical frailty to global and everyday cognitive functioning in older adults. Methods: Data came from 1,396 community-dwelling, healthy Chinese older adults aged 65 or above. We measured their global cognition using the Cantonese Chinese Montreal Cognitive Assessment (MoCA), everyday cognitive functioning with the short Chinese Lawton Instrumental Activities Daily Living scale (IADLs-4 item), and physical frailty using the Fatigue, Resistance, Ambulation, Illness, and Loss of Weight Scale (FRAIL) and grip strength. Multiple regression analysis was used to evaluate the comparative roles of age and physical frailty in the two cognitive outcomes. Results: Both age and physical frailty were found to contribute significantly to global and everyday cognitive functioning. In the global cognition model, age explained 12% and physical frailty explained 8% of the unique variances after controlling for the effects of gender and education. 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 cognitive functioning 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, and also give weight to intervention targeting physical frailty.