Cross-cultural study of caregiver burden for Alzheimer's disease in Japan and Taiwan: result from Dementia Research in Kumamoto and Tainan (DeReKaT).

Background: Caregiver burden (CB) of Alzheimer's disease (AD) in Taiwan is becoming an urgent social issue as well as that in Japan. The comparison of CB may explain how caregiver feels burden in each country.
Methods: The participants were 343 outpatients with AD and their caregivers of Japan (n = 230) and Taiwan (n = 113). We assessed the CB using the Japanese and Chinese version of Zarit Caregiver Burden Interview (ZBI). The initial analysis was an exploratory factor analysis for each group to confirm the factor structure of ZBI. Then, the multiple-group structural equation modeling (MG-SEM) was used to assess the measurement invariance of ZBI such as configural, metric, and scalar invariances. Lastly, we compared the latent factor means of the ZBI between Japan and Taiwan.
Results: In both groups, the confirmatory factor analysis extracted 3 factors which were labeled "Impact on caregiver's life", "Embarrassed/anger", and "Dependency". The MG-SEM indicated an acceptable model fit, and established the partial scalar measurement invariance (comparative fit index (CFI) = 0.901, root mean square error of approximation (RMSEA) = 0.066). When we compared the latent factor means, the score of "Impact on caregiver's life" in Taiwanese caregivers was significantly higher than that in Japanese (p = 0.001). However, "Dependency" in Taiwanese caregivers was lower than that in Japanese (p < 0.001).
Conclusions: Partial measurement invariance allowed comparing the latent factor mean across two countries. The results of comparisons suggested that there may be differences in the way of feeling CB between Japan and Taiwan.