Relative Deprivation in Income and Mortality in Japanese Older Adults

AGES Cohort Study

Abstract

Relative deprivation hypothesis posits that relative deprivation in income or social status compared to others can cause psychosocial stress and poor health independent of absolute income. We evaluated this hypothesis using AGES data, a large-scale data of Japanese older (aged 65+) adults. Participants of the 2003 AGES baseline survey were individually linked with death information between 2003 and 2007 that were identified by the public long-term care insurance payment data base. We used data of 16,023 participants without missing data on primary variables, who were independent in terms of basic activities of daily living and residing in eight municipalities in Aichi and Kochi prefectures at baseline. Relative deprivation compared to others in the same sex, age group, and/or municipality was calculated using a modified version of Yitzhaki index. During our follow-up, 1,236 deaths were identified. Cox's proportional hazard regression revealed that, even adjusting for absolute household income, age, marital status, educational attainment, and medical treatment history, 1SD unit increase in income deprivation relative to others in the same sex, age group, and municipality was associated with increased death hazard (95% confidence intervals) of 1.20 (1.06-1.36) in men and 1.17 (0.97-1.41) in women. Further adjustment for lifestyle risks (smoking, alcohol consumption, and preventive care utilization) slightly attenuated the hazards estimated. Relative deprivation in income may increase mortality risks regardless of absolute income in Japanese older adults, and the impact may slightly larger among males.