[Cross-validation of the short version of the Japanese version of the Zarit Caregiver Burden Interview (J-ZBI_8)].

This study was aimed at confirming the cross-validity and construct validity of the short version of the Japanese version of the Zarit Caregiver Burden Interview (J-ZBI_8) developed by Arai and colleagues. A total of 169 family members caring for disabled elderly were assessed by a self-administered questionnaire which included the Japanese version of the Zarit Caregiver Burden Interview (J-ZBI). Cronbach's alpha of the J-ZBI_8 was 0.88, indicating a high reliability of this instrument. A confirmatory factor analysis revealed that the two factor model of J-ZBI_8 fitted the data. Pearson's correlation coefficient between J-ZBI_8 and J-ZBI was 0.92; and the correlation coefficient between J-ZBI_8 and item 22 (a single global burden) was 0.66. These data indicated that J-ZBI_8 had a high concurrent validity. The J-ZBI_8 was found to be significantly correlated with Barthel Index, duration of caring, hours of caregiving/day, physical fatigue and mental fatigue among caregivers, but not with the duration of caring (months). Caregivers of disabled elderly who did not have any behavioral disturbances had a significantly lower J-ZBI_8 score than those who were caring for elderly with such behaviors. Also, caregivers who declared that they did not abuse disabled elderly had a significantly lower J-ZBI_8 score than those who replied they abused them, when compared by t-test. These results indicated that J-ZBI_8 had a high construct validity. It is concluded that the J-ZBI_8 had a high cross-validity and construct validity. This instrument can thus facilitate the assessment of family caregiver burden in clinical settings.