Sense of life worth living (ikigai) and incident functional disability in elderly Japanese: The Tsurugaya Project

doi:10.1016/j.jpsychores.2017.02.013

Journal of Psychosomatic Research

Volume 95, April 2017, Pages 62-67

https://doi.org/10.1016/j.jpsychores.2017.02.013 Get rights and content

Highlights

•
Relationship between ikigai (a sense of life worth living) and incident disability was examined among elderly Japanese.
•
A stronger degree of ikigai is significantly associated with a lower risk of incident functional disability.
•
This relationship did not alter even after multivariate adjustment (depressive symptoms, lower functional mobility, etc.).

Abstract

Objective

To test the hypothesis that elderly persons who feel ikigai (a sense of life worth living) have a lower risk of incident functional disability than those who do not. Recent studies have suggested that ikigai impacts on mortality. However, its impact upon disability is unknown. The aim of the present study was to investigate the association between ikigai and incident functional disability among elderly persons.

Methods

We conducted a prospective cohort study of 830 Japanese elderly persons aged ≥ 70 years as a comprehensive geriatric assessment in 2003. Information on ikigai was collected by self-reported questionnaire. Data on functional disability were retrieved from the public Long-term Care Insurance database in which participants were followed up for 12 years. Hazard ratios (HRs) and 95% confidence intervals (CIs) for incidence of functional disability were calculated for three groups delineated according to the presence of ikigai (“no”, “uncertain” or “yes”) using the Cox proportional hazards regression model.

Results

The 12-year incidence of functional disability was 53.3% (442 cases). As compared with the “no” group, the multiple-adjusted HR (95% CI) of incident functional disability was 0.61 (0.36–1.02) for the “uncertain” group and 0.50 (0.30–0.84) for the “yes” group.

Conclusion

A stronger degree of ikigai is significantly associated with a lower risk of incident functional disability.

Introduction

Previous studies have proved that a positive psychological state is associated with a lower risk of mortality [1], incident coronary heart disease [2] and stroke [3].

In Japanese culture, having a sense of “life worth living” (ikigai) is a commonly used indicator of subjective well-being. Ikigai does not merely reflect an individual's psychological factors (well-being, hopes) but also consciousness about his/her motivation for living [4], because it has a meaning akin to having a “purpose in life” or a “reason for living”. In the most authoritative dictionary used in Japan, ikigai is described as “joy and a sense of well-being from being alive” and “realizing the value of being alive” [5].

Recently, we and other researchers have indicated that people with ikigai have a lower risk of mortality than those who do not feel it [6], [7], [8], [9], [10]. The increase in mortality risk has been attributed to cardiovascular disease, especially stroke [6]. Because stroke is one of the major causes of functional disability, it is expected that ikigai would contribute to disability prevention. However, we have not found any previous studies examining the association between ikigai and incident risk of disability.

In the present study, we attempted to test the hypothesis that elderly persons who feel ikigai have a lower risk of incident functional disability than those who do not.

Section snippets

Participants

The Tsurugaya Project was a comprehensive geriatric assessment implemented in 2003 that included medical status as well as physical and cognitive functions [11], [12]. Among 2925 community-dwelling elderly people aged 70 or more and living in the Tsurugaya area of Sendai city (Japan), 906 provided written informed consent to participate in the study and agreement to review their Long-term Care Insurance (LTCI) information. We excluded some participants who had already been LTCI-certificated as

Results

Over 12 years of follow-up, the number of participants with functional disability was 442, and the total number of deaths without functional disability was 207. Moreover, 41 participants moved out.

Among the 830 participants, 640 (77.1%) felt ikigai, 163 (19.6%) were uncertain, and 27 (3.3%) did not feel ikigai. Table 1 shows that, as compared with participants who felt ikigai, those who did not showed a tendency to have obvious depressive symptoms, moderate or severe bodily pain, and were more

Discussion

In this population-based cohort study, we found significant inverse dose-response associations between a stronger degree of ikigai and incident functional disability in an elderly population. This relationship did not alter even after adjustment for potential confounding factors. Subjects who did not feel ikigai were more likely to have depressive symptoms, lower functional mobility, lower IADL, and lack of social support, but the risk of incident functional disability in subjects who felt

Conflict of interest

The authors have no competing interests to report.

Funding

This work was supported by Health Sciences Research grants [no. H28-Junkankitou-Ippan-008] from the Ministry of Health, Labour and Welfare, Japan.

Acknowledgements

We would like to thank Yoshiko Nakata and Mami Takahashi for their technical assistance.

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Sense of life worth living (ikigai) and incident functional disability in elderly Japanese: The Tsurugaya Project

Highlights

Abstract

Objective

Methods

Results

Conclusion

Introduction

Section snippets

Participants

Results

Discussion

Conflict of interest

Funding

Acknowledgements

J. Psychosom. Res.

Am. J. Clin. Nutr.

J. Psychiatr. Res.

Arch. Gerontol. Geriatr.

Am. J. Geriatr. Psychiatry

Positive psychological well-being and mortality: a quantitative review of prospective observational studies

Psychosom. Med.

A prospective study of positive psychological well-being and coronary heart disease

Health Psychol.

The association between emotional well-being and the incidence of stroke in older adults

Psychosom. Med.

Japan's silver human resource centers and participant well-being

J. Cross Cult. Gerontol.

Koujien (Japanese Dictionary)

Sense of life worth living (ikigai) and mortality in Japan: Ohsaki study

Psychosom. Med.

Effect of having a sense of purpose in life on the risk of death from cardiovascular diseases

J. Epidemiol.

Relationship between self-assessed masticatory disability and 9-year mortality in a cohort of community-residing elderly people

J. Am. Geriatr. Soc.

Relationships between walking hours, sleeping hours, meaningfulness of life (Ikigai) and mortality in the elderly: prospective cohort study

Japanese J. Hyg.

Relationship between serum isoflavone levels and disability-free survival among community-dwelling elderly individuals: nested case-control study of the Tsurugaya Project

J. Gerontol. Ser. A Biol. Sci. Med. Sci.