Reliability, Validity and Reference Values of the Zarit Burden Interview for Assessing Informal Caregivers of Community-Dwelling Older Persons with Dementia

ABSTRACT Zarit Burden Interview (ZBI) is the most widely used instrument for assessing the burden experienced by the caregivers of persons with dementia. As part of the Canadian Study of Health and Aging, the 22-item ZBI was administered to a representative sample of 312 informal caregivers of community-dwelling subjects with dementia. The mean score was 22.4 out of 88 (sd: 16.2) and the median score was 18.5, which is far lower than those reported in previous studies using this instrument with convenience samples. There was no significant difference in the burden score according to the age, gender, living arrangement, marital status or employment status of the caregiver. The ZBI score was more strongly correlated to the depressive mood of the caregivers (r = 0.59) and the behaviour problems of the care recipients (r = 0.64) than their cognitive (r = 0.32) and functional (r = 0.31) status. Following a factor analysis, a 12-item short version of the instrument is proposed with two factors: personal strain (3 items) and role strain (9 items).