Factor Structure and Invariance of the Quality of Life in Alzheimer's Disease (QoL-AD) Scale

Abstract

The factor structure and factorial invariance of the Quality of Life in Alzheimer's Disease (QoL-AD) Scale was investigated in a sample of 653 nondemented, community-dwelling older adults, ages 57 to 95 years (M = 71.62, SD = 8.86), from the Seattle Longitudinal Study. The total sample was split into two random halves to explore and confirm the structure of the QoL-AD. Confirmatory factor analyses indicated better fit for a three-factor solution than one- or two-factor solutions. Weak factorial invariance was found for the three-factor solution (Physical, Social, and Psychological Well-being) across age group and gender. These findings may help to establish a baseline quality of life before the onset of any noticeable AD symptoms.

This research was supported by a grant from the National Institute on Aging (R37 AG08055) to K. Warner Schaie and by a National Institute on Mental Health training grant, Training in Research and Mental Health and Aging (T32 MH18904). An earlier version of this paper was presented at the annual scientific meeting of The Gerontological Society of America. The authors gratefully acknowledge the enthusiastic cooperation of the members and staff of the Group Health Cooperative of Puget Sound.

Notes

Note. Young-old = 57–74 years; Old-old = 75–95 years.

∗∗∗p < .001.

Note. Factor loadings are standardized regression coefficients. All values are significant at p < .001.

Note. Young-old = 57–74 years; Old-old = 75–95 years.

∗∗∗p < .001.