Reliability, validity and reference values of the Zarit Burden Interview for assessing informal caregivers of community-dwelling older persons with dementia

Zarit Burden Interview (ZBI) is the most widely used instrument for assessi ng the burden experienced by the caregivers of persons with dementia. As pa rt of the Canadian Study of Health and Aging, the 22-item ZBI was administe red to a representative sample of 312 informal caregivers of community-dwel ling subjects with dementia. The mean score was 22.4 out of 88 (sd: 16.2) a nd the median score was 18.5, which is far lower than those reported in pre vious studies using this instrument with convenience samples. There was no significant difference in the burden score according to the age, gender, li ving arrangement, marital status or employment status of the caregiver. The ZBI score was more strongly correlated to the depressive mood of the careg ivers (r = 0.59) and the behaviour problems of the care recipients (r = 0.6 4) than their cognitive (r = 0.32) and functional (r = 0.31) status. Follow ing a factor analysis, a 12-item short version of the instrument is propose d with two factors: personal strain (3 items) and role strain (9 items).