Introduction  

Across the globe, costs related to functional disabilities and long-term care (LTC) are rapidly increasing in societies with ageing populations. Expenses are greater among those with more severe impairments.1 In Japan, in one of the countries experiencing the highest rate of ageing, the proportion of older people is currently 27.3% and is predicted to reach around 40% by 2065.2 Under these circumstances, the costs for LTC insurance (LTCI) are expected to rise from US$100 billion in 2016 to US$210 billion by 2025.

Lowering these costs requires building a sustainable and healthy ageing society which means developing and maintaining the functional ability that enables well-being in older age. The Japanese government implemented a public nursing care insurance law that includes an LTC prevention policy.3 For this policy, a population approach as primary prevention was proposed rather than a high-risk one which was grounded in risk screening based on intervention targeting. Promoting social participation is considered an effective intervention regarding the population approach, which focuses on the entire group of older adults in a community.

Although social participation is an ambiguous concept, Bukov distinguished three types of participation: collective, productive and political.4 In this paper, we focused on involvement in collective activities in formal and informal societal groups at local community. Social participation helps maintain social networks, support and roles, raises self-esteem and self-efficacy and facilitates access to various kinds of information. Several international systematic reviews and meta-analyses have reported on the physical, psychological and social benefits of social participation among older people.5–10 For instance, meta-analysis across 148 articles mentioned active engagement in social activities could reduce risk for mortality. In particular, previous observational studies in Japan also found that collective social participation activities such as volunteering, sports clubs and hobbies among older adults lowered the risk of developing depressive symptoms,11–13 the incidence of functional disabilities,14–16 cognitive decline or dementia,17 18 falls19 and immature death.20–23

We hypothesise that if social participation extends healthy life expectancy and reduces the time spent in intensive nursing care, then the cumulative cost of LTCI services might be lower among the participants; however, to our knowledge, there is no evidence that social participation lessens it. In addition, Japanese LTCI services are provided mainly when people aged 65 and over come to require care or support, based on investigation for certification and doctor’s written opinion. The cost of LTCI services is one of the most important issues for the public sector as an insurer. The evidence for contributing to cost-saving has been useful for recent intervention financing schemes that provide economic incentives to service providers, for instance, social impact bonds. In this paper, using data from a follow-up study that took place over a period of 11 years and tracked older Japanese adults, we assessed the differences of the duration period of requiring care level and of the cumulative cost of LTCI services by frequency of social participation in baseline survey.

Methods

Study design

The Japan Gerontological Evaluation Study conducted a self-administered questionnaire in March 2006 as a baseline; 5483 respondents who were 65 years or older, physically and cognitively independent and not eligible for public LTCI benefits were selected using a complete enumeration; they live in the city of Tokoname in Aichi Prefecture (response rate=53.4%: 5483/10 274). In addition, our subjects were more healthy or active older adults at baseline, because Japanese LTCI certifies the people included mild care needs, not only severe care level. Afterwards, we obtained receipt data on LTCI benefits over a period of 11 years after the baseline survey from government database of public LTCI. After eliminating respondents who lacked information on sex and age (n=42), who had moved out of their residence (n=38) and who had been certified for LTCI before the baseline survey (n=26), 5377 respondents were linked to the LTCI receipt data set (figure 1).

• Download figure
• Open in new tab
• Download powerpoint

Figure 1

Flow chart of respondent selection. LTCI, long-term care insurance.

Explanatory variables: social participation

As mentioned above, social participation is an ambiguous concept. The indicator of social participation was taken from the Japanese General Social Survey,25 and categorised organisations into following eight types as collective social participation activities: hobby activities group, sports group or club, volunteer group, neighbourhood association, senior citizen club/firefighting team, religious group, political organisation or group, industrial or trade association and citizen or consumer group. We focused on the three groups/organisations previously identified as being associated with lower risks for functional disabilities: hobby activities group,17 23 sports group or club15 23 and volunteer group.26 27 According to principal components analysis, these community activities were categorised to horizontal organisations.28 29 Respondents were asked how often they took part in these activities. We categorised them to the four frequencies, respectively: never, a few times a year, once or twice a month and once a week or more.

Covariates

Demographic variables included sex, age, educational attainment, equivalent income (US$), marital status and living situation at the baseline survey. It is well known that these are basic variables as social determinants of health. Age was a continuous variable (73.4±6.2). Years of education was categorised as <6, 6–9, 10–12 and 13+. We equalised household income by the square root of the numbers and classified it as <20.0, 20.0–39.9 and 40.0+ thousand USD. Marital status consisted of married, widowed, divorced and never married. Living situation was categorised as living alone, with one’s spouse only, with a child or with others such as grandchildren, siblings and relatives.

In order to account for the health status at the baseline, the presence of disease or impairment and self-rated health were considered. The presence of disease or impairment was based on self-reported medical condition (no illness, having illness but need no treatment, having illness but discontinued treatment and receiving some treatment). We dichotomised it, that is, no illness or not. We assessed self-rated health using four categories: excellent, good, fair and poor.

Results

Table 1 shows the characteristics of the respondents; the mean age at the baseline was 73.4; 52.0% of the respondents were men. Out of this amount, 30.4% had used LTCI services at least once, and 28.4% passed away during the follow-up period. The average of the cumulative cost of LTCI services during the follow-up period was US$13.7 thousand. The distribution of that was skewed right. There were significant differences in the average duration for the level of care required for social participation across the whole population during the follow-up period (table 2). Non-participants in groups for hobbies, sports and volunteering had a longer duration of certification for LTC at all care levels. For example, among participants who took part in the group for hobbies, the average duration for non-participants was 14.1 (SD=25.8) months, whereas that of those who participated ‘once a week or more’ was 10.6 (SD=21.6) months.

The classical regression model showed that in comparison to non-participants, respondents who participated in the group for hobbies once a week produced a cost containment in US$3.6 (95% CI 6.0 to 1.3) thousand, which was lower per person for LTCI cumulative costs over the 11-year period (table 3). Likewise, participating in a sports club was also significantly associated with lower LTCI costs: the category of those who took part ‘once a week or more’ was US$4.9 (95% CI 6.9 to 2.8) thousand less per person. However, in the volunteer group, only less frequent participation was associated with lower costs; for individuals in the category of ‘a few times a year’, this figure was US$4.1 (95% CI 7.1 to 1.0) thousand less per person. When we changed the estimation method to GLM, and when we adopted OLS after multiple imputation, the major results and trends were similar to the above, although some point estimations in GLM were higher in the categories that had a small sample size (please see online supplementary table S1).

The estimations of IPW showed similar outcomes. In comparison to non-participants, going to a group for hobbies once a week or more resulted in a cost that was reduced by approximately US$3.5 (95% CI 6.2 to 0.8) thousand; for sports clubs, this lowered figure was approximately US$6.1 (95% CI 9.3 to 2.8) thousand. The significant relationship with less frequent participation in the volunteer group disappeared, but the direction of the association and point estimations did not largely change (the C statistics in these models are shown in online supplementary table S2).

In addition, in comparison to non-participants, for deceased individuals during the follow-up period, joining a group for hobbies (once a week+) or sports (once a week+) led to a reduced cost of approximately US$3.9 to US$5.7 thousand and US$9.4 to US$11.4 thousand, respectively (please see online supplementary table S3). These outcomes are preliminary because there were very few analysed subjects (especially the sports and volunteer groups).

Discussions

According to the 11-year prospective cohort study of healthy Japanese older adults, compared with non-participants, respondents who took part in hobby groups or sports activities once a week incurred lower costs for LTCI services (approximately US$3.5 and US$6.1 thousand, respectively, per person), even after demographic variables and health status at baseline were controlled.

These findings are consistent with those of previous research in which several longitudinal studies have shown that older adults who participate in social activities have lower risks of disability,33 functional declines34 35 and mobility declines.36 37 Moreover, it has been suggested that participation in hobby groups, sports clubs and volunteer groups might contribute to reducing the incidence of physical disability risks.15 17 23 26 27 In an intervention study examining the effect of community salons in Japan, it was reported that the incidence of physical disability risks among participants fell by 51% over 5 years38 and that cognitive disability risks declined by around 30% over 7 years.39 Several trajectory analyses have shown that attending leisure activities is related to ‘functional maintenance,’40 while a low frequency of going outside the home was related to being ‘persistently disabled.’41

This study adds evidence to the current literature suggesting that social participation may be effective not only for preventing functional deterioration but also in terms of reducing LTC costs. Our findings also illustrate that the more the respondents took part in each type of community activity, the less time they spent in intensive nursing care. Although the mechanisms behind the relationship between collective social participation and LTCI costs are not fully understood, participating in community activities might contribute to the promotion of physical activities, the maintenance of social role and social networks and the acquisition of important health-related information. Therefore, differences in LTCI costs may have arisen due to extensions to healthy life expectancy or reductions in the periods of functional disability, rather than restrictions on the use of the required services. Lifetime LTCI costs, which were estimated among deceased individuals, showed similar trends. This suggests that postponing the onset of functional disabilities or death did not cause the differences in costs.

On the other hand, for volunteer activities, less frequent (rather than very frequent) participation resulted in lower LTCI costs. In Japan, it has often been mentioned that a portion of those participating in volunteer activities shoulder excessive burdens in terms of supporting those activities, and official Japanese statistics have revealed that half of older adults preferred volunteer activities that do not constrain their time.42 Our results also suggest that being forced to take part in volunteer activities, which is counter to the intended meaning of volunteering, might not necessarily protect the participant’s health, even though participating in and of itself has preventive effects.

It is clear that this study has public health implications. For example, one systematic review mentioned that most local and national public health interventions are aimed at cost saving,43 and our results suggest that promoting participation in community activities might have a non-ignorable cost-containment effect. More specifically, 21.8% and 12.7% of the respondents, or about 2240 and 1300 people, in this municipality may have been participating in hobby or sports groups at least once a week. If those numbers were 10% higher (approximately 220 and 130 people), it may have been possible to reduce the cumulative cost of LTCI services by approximately US$780 to US$800 and US$630 to US$790 thousand, respectively, over an 11-year period. It is important to note that each activities discussed in this paper are not special programmes, and that all of them are already common in Japan. Hence, the additional expenditures to be borne by the public sector would be comparatively minor. It is also suggested that an accumulation of cost impact analyses might be meaningful in terms of public health and community work research. Furthermore, our findings might even be an underestimation because less frequent categories for each type of social participation tend to result in higher mortality rates.

Our study has several limitations and strengths. First, due to restricted data accessibility, we could not analyse medical care costs, which is significant because a previous study mentioned that medical care and LTC expenditures have a weak, but negative, relationship.44 However, to the best of our knowledge, our study is the first to demonstrate that social participations among older adults might help lower subsequent LTCI costs. Second, we assessed social participation variables and covariates only at the baseline. More specifically, our study only analysed healthy older adults, excluding those with physically and cognitively disabilities. We also controlled for multiple health dimensions and other covariates by adopting several statistical techniques. However, since the baseline survey was based on a self-reported questionnaire, we cannot deny the possibility of reverse causation. Third, generalisability might be limited by the fact that our study was conducted in one municipality, even though the proportions of older adults and certified LTC levels between the subject area and the national average are roughly the same. Furthermore, selection bias might have occurred because the response rate in our baseline survey was not high (53.4%). However, there are important conclusions that can be drawn from an analysis of merged individual data from this questionnaire regarding social life and public receipt data as they pertain to LTC services. Fourth, there might be measurement bias regarding the actual social participation levels because the data were derived solely from responses to the self-reported questionnaire. Although our indicators have often been used in previous surveys, it is possible that the self-reported activities do not reflect actual participation levels. To assess the frequency and role of these groups, future research should examine interactions among participating members using more objective indicators.