Mothers and daughters-in-law: a prospective study of informal care-giving arrangements and survival in Japan.
BACKGROUND
Daughters-in-law have played an important role in informal care-giving arrangements within East Asian traditional norms. The aim of this study was to measure the impact of daughter-in-law care-giving on the survival of care recipients. We prospectively examined the associations between different types of kinship relationship between the main family caregiver and the care recipient in relation to survival among care recipients.


METHODS
A questionnaire was administered to Japanese community-dwelling seniors who were eligible to receive national long-term care insurance (LTCI) community-based services. Among 191 individuals whose informal care-giving arrangement was definitively determined, we observed 58 care recipients receiving care from spouses, 58 from daughters-in-law, 27 from biological daughters, 25 from other relatives, and 23 care recipients living alone.


RESULTS
During 51 months of follow-up from December 2001, 68 care recipients died, 117 survived, and 6 moved. Hazard ratios of each care-giving arrangement were estimated by Cox proportional hazard models adjusted for care recipients' demographic factors, their care needs level based on their physical and cognitive functioning and their service use, caregivers' demographic factors, and household size. The highest risk of mortality was found for female elders receiving care from daughters-in-law (HR 4.15, 95% CI 1.02-16.90) followed by those receiving care from biological daughters (HR 1.64, 95% CI 0.37-7.21), compared to women receiving spousal care. By contrast, male elders receiving care from daughters-in-law tended to live longer than those receiving care from their spouses.


CONCLUSIONS
Our finding suggests that there may be a survival "penalty" for older Japanese women who are cared for by their daughters-in-law.
Nishi
Akihiro
A
Department of Health Services Research, Graduate School of Comprehensive Human Sciences, University of Tsukuba, Ibaraki, Japan.
Tamiya
Nanako
N
Kashiwagi
Masayo
M
Takahashi
Hideto
H
Sato
Mikiya
M
Kawachi
Ichiro
I
D000368:Aged; D000369:Aged, 80 and over; D017028:Caregivers / Q000639:trends*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D016901:Intergenerational Relations / Q000208:ethnology*; D007564:Japan / Q000208:ethnology; D008297:Male; D008875:Middle Aged; D009035:Mothers; D009679:Nuclear Family / Q000208:ethnology; D011446:Prospective Studies; D015996:Survival Rate / Q000639:trends
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