Elsevier

Preventive Medicine

Volume 155, February 2022, 106945
Preventive Medicine

Does laughing with others lower the risk of functional disability among older Japanese adults? The JAGES prospective cohort study

https://doi.org/10.1016/j.ypmed.2021.106945Get rights and content

Highlights

  • Laughing with others was associated with a reduced risk of functional disability.

  • The more people laugh with others, the lower the risk of functional disability.

  • Laughing with friends reduced the risk of functional disability by more than 30%.

Abstract

While laughter is evoked mainly in social contexts, the potential link between laughter in daily life and health benefits is unclear. This study aimed to examine the association between laughter in daily life and the onset of functional disability among older adults in Japan. Data were obtained from a 6-year follow-up cohort of 12,571 participants (46.1% male) in the Japan Gerontological Evaluation Study, aged ≥65 years, who could independently perform daily activities. We evaluated their laughter in daily life from three perspectives: the types of situations in which people laugh, the number of situations in which people laugh with others, and the persons with whom people laugh. Using the Cox proportional hazards model, the risk of functional disability was estimated. A total of 1420 functional disabilities were observed during follow-up. After adjusting for potential confounders, participants who laughed with others (e.g., during conversations with friends) were at a reduced risk of functional disability (hazard ratio, 0.77; 95% confidence interval, 0.65–0.92) than those who laughed alone (e.g., during watching television). Similarly, the number of situations to laugh with others was inversely associated with the risk of functional disability (Ptrend < 0.001). Laughing in a conversation with friends reduced the risk of functional disability by approximately 30% compared to laughing alone. Overall, laughing with others was associated with a reduced risk of functional disability. Having more situations to laugh with others or at least the situation to laugh with friends might contribute to reducing the risk of functional disability later in life.

Introduction

Over the last few decades, while healthy life expectancy has increased worldwide, life expectancy with disability has also increased (GBD 2017 DALYs and HALE Collaborators, 2018). To address this issue, the World Health Organization defined and promoted healthy aging as “the process of developing and maintaining the functional ability that enables well-being in older age (World Health Organization, 2021).” In 2020, the United Nations General Assembly declared 2021–2030 as the decade of healthy aging (United Nations, 2020), and aimed to optimize older people's functional ability (World Health Organization, 2021). To achieve this goal, evidence from Japan, which has had the highest proportion of individuals aged ≥65 years in the world for many years, is warranted.

Laughter is evoked mainly in social contexts, such as casual conversations, and laughter in daily life is believed to have health benefits. In recent years, a growing number of studies have focused on the link between laughter in daily life and several health outcomes (Hayashi et al., 2016; Ikeda et al., 2021; Sakurada et al., 2020; Tamada et al., 2021). We have previously reported an inverse association between the daily frequency of laughter and onset of functional disability in a large general population of independent older adults (Tamada et al., 2021). However, most of the epidemiological studies on laughter in daily life have focused only on the frequency of laughter, with little focus on the types of situations in which laughter occurs (e.g., laughing alone or with others). However, in a different research field, recent exercise epidemiology studies of older adults suggest that exercising with others can be more beneficial than exercising alone for various health outcomes, including functional disability (Fujii et al., 2020; Kanamori et al., 2012; Seino et al., 2019). Likewise, regarding the role of laughter in the lives of older adults, laughing with others may have additional health benefits compared to laughing alone, through the enhancement of social relationships, such as social connectedness and social support (Cohen, 2004; Holt-Lunstad et al., 2010).

This prospective cohort study aimed to investigate the association between laughter in daily life and the onset of functional disability among older adults in Japan. We evaluated laughter in daily life from three perspectives: the types of situations in which people laugh, the number of situations in which people laugh with others, and the persons with whom people laugh. We hypothesized that there would be a lower risk of onset of functional disability among those laughing with others compared to those laughing alone. The secondary hypothesis was that individuals with more situations to laugh with others would be less likely to develop functional disabilities. The third hypothesis predicted was that the degree of the potential preventive effect of laughing with others on functional disability would depend on the person with whom people laugh.

Section snippets

Study population and setting

This study was based on cohort data from the Japan Gerontological Evaluation Study (JAGES), which was established in 2010 with the aim of examining the factors associated with the health and well-being in older adults (Kondo et al., 2018; Kondo, 2016). We used data from the 2013 wave, conducted between October and December 2013. In the 2013 wave, participants were randomly recruited or completely enumerated from 30 municipalities throughout Japan. Self-reported questionnaires were mailed to

Results

Table 1 shows the baseline characteristics of the study population according to the types of situations of laughter. Of the respondents, 69.0% laughed in both situations, 21.4% laughed with others, and 9.5% laughed alone. A summary of the situations in which people laugh in daily life by age category is presented in Supplemental Table 1. The most common situation that evoked laughter was watching television and videos (74.2%), followed by conversations with friends (66.3%).

Table 2 shows the

Discussion

This prospective cohort study of independent older adults demonstrated an association between laughter in daily life and the onset of functional disability, indicating that participants who laughed with others were at reduced risk of developing functional disability. Similarly, after carefully controlling for potential confounders, the number of situations in which people laugh with others was inversely associated with the risk of functional disability. In particular, laughing in a conversation

Conclusion

In conclusion, this study revealed that laughing with others was associated with a reduced risk of functional disability among older Japanese adults. Laughing with others, especially friends, may contribute to reducing the risk of functional disability later in life.

Declaration of Competing Interest

The authors declare they have no conflict of interest with respect to this research study and paper.

Acknowledgments

We are grateful to the subjects who participated in this study. YT was supported by Nagoya University CIBoG program from MEXT WISE program.

Funding

This study used data from JAGES (the Japan Gerontological Evaluation Study). This study was supported by Grant-in-Aid for Scientific Research (15H01972, 15H04781, 15H05059, 15K03417, 15K03982, 15K16181, 15K17232, 15K18174, 15K19241, 15K21266, 15KT0007, 15KT0097, 16H05556, 16K09122, 16K00913, 16K02025, 16K12964, 16K13443, 16K16295, 16K16595, 16K16633, 16K17256, 16K17281, 16K19247, 16K19267, 16K21461, 16K21465, 16KK0059, 16KT0014, 17K04305, 17K34567, 17K04306, 25253052, 25713027, 26285138,

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