Perceived Level of Life Enjoyment and Risk of Developing Disabling Dementia: The Japan Public Health Center–Based Study

Life enjoyment, linked to the ability to engage pleasurably with one's environment, may be related to the risk of developing dementia. This prospective cohort study examined the association between level of life enjoyment and disabling dementia incidence among Japanese community residents.The participants were Japanese, aged 45-74 years old at five-years follow-up, in the Japan Public Health Center-based (JPHC) study (N=38,660). Psychological conditions and other confounding variables were identified through self-administered questionnaires. Incident disabling dementia registered based on the Japan's Long-Term Care Insurance (LTCI) System from 2006 to 2016. Hazard ratios [95% confidence intervals] were assessed using Cox proportional hazards models.Over a median follow-up period of 9.4 years, a total of 4,462 cases of disabling dementia developed. Level of life enjoyment was inversely associated with the risk of disabling dementia: the multivariable hazard ratios were 0.75[0.67-0.84] (p <.001) and 0.68[0.59-0.78] (p <.001) with medium and high life enjoyment, respectively, compared to low life enjoyment. Furthermore, the association between greater life enjoyment and low risk for disabling dementia was strongest in the subgroup with low-medium mental stress. In the high mental stress group, this association was evident for post-stroke disabling dementia, but not for disabling dementia without a history of stroke.A higher level of life enjoyment was associated with a lower risk of disabling dementia, particularly in the low-medium mental stress group. This finding suggests the importance of having life enjoyment by managing mental stress for reducing risk of disabling dementia.