Introduction

Life expectancy has risen significantly as the economy has continued to grow and medical technology advances. However, this trend has resulted in the formidable task of a rapidly ageing population. According to the National Bureau of Statistics’ 2021 forecast, China is expected to have roughly 267 million people aged 60 and up, representing 18.9% of the total population1. Furthermore, estimates show that by 2050, this demographic will exceed 400 million, with a rising number of people over the age of 65. Not only in China, but also in Japan, which has a low fertility rate and an aging population; by 2025, one-third of the population will be over the age of 652. In the United States, it is expected that by 2030, one in every five people (20.0% of the population) will be 65 years or older, with the number of people 65 and older more than doubling to almost 70 million3. Brazil and the United Kingdom are likewise devoted to addressing a variety of age-related challenges. Global life expectancy will rise by 5 years, and the population aged 60 and more is expected to grow from 202 million in 1950 to 3.1 billion in 2100, an absolute increase of 15.2 times4,5. As people age, a variety of factors have a substantial impact on their cognitive performance, potentially ranging from normal to mild cognitive impairment or dementia. Impaired cognitive function not only reduces the quality of life for older persons by affecting their mental well-being and increasing mortality risks, but it also places significant economic and caregiving costs on families and society as a whole. For example, in 2019, over 16 million family members and unpaid caregivers in the US provided approximately 18.6 billion hours of care for people with dementia, valued at nearly $244 billion. In Japan, the social cost of dementia was estimated to be ¥14.1 trillion ($112.7 billion) in 2014 and is projected to reach ¥24.3 trillion ($188.9 billion) in 20606. For China’s enormous population base, the situation is considerably more severe. In light of these trends, addressing ways to prevent cognitive decline in the elderly in order to maintain cognitive function is a critical component of the Healthy China agenda and has arisen as a major area of research.

Previous research has indicated that age, years of schooling, physical activity, smoking, social interaction, chronic diseases, dietary patterns, leisure activities, and area of living can all influence cognitive function in the elderly7,8,9,10,11,12. Many previous studies have also confirmed the relationship between leisure activities and cognitive function8,13,14. A queue study found that the higher the frequency of leisure activities, the greater the likelihood of reversing mild cognitive impairment(MCI)8. At the same time, active leisure activities can significantly reduce the risk of death by 41%.15 In conclusion, leisure activity play a positive role in the health of older adults, not merely in cognitive function. Between leisure activities and cognitive function, the study found a mediating effect of anxiety, which plays a partial role14.

A variety of mediating effects between leisure activities and cognitive function need to be investigated. First and foremost, this study focuses on individual evaluation, which incorporates both life happiness and health satisfaction. As a result, the literature evaluation is organized around the themes of life satisfaction and health. Jin et al. observed that poor life satisfaction had a deleterious influence on cognitive function, regardless of population variations16. Liu et al. discovered that life satisfaction mediates the association between pregnant stress and depression, and it is strongly adversely connected with depression17. Health satisfaction is self-reported based on an individual’s health, and a large number of previous studies have found a positive effect of leisure activities on health, confirmed the protective effect of a healthy physical condition on cognitive function18,19,20. A study by Guney also found that people who experience anxiety and depression have lower life satisfaction, and higher life satisfaction is also due to more leisure activities21,22. Chen et al. Discovered that the gap between life satisfaction and health satisfaction is a risk factor for depression23.The study verified the link between frailty and cognitive functioning and discovered that depression played a mediation role24,implying that older persons in poor physical health have inferior cognitive function. In summary, it is claimed that individual evaluation plays a mediating role in the relationship between leisure activities and cognitive function.Anxiety and depression are prevalent disorders among the elderly, and they can exacerbate each other. Yang et al. discovered that the presence of anxiety or depression is an independent risk factor for cognitive impairment17. Some studies have also discovered that anxiety and depression are highly comorbid, and that when they coexist, the risk increases25,26. According to Werner’s research, anxiety and depression can be early predictors of cognitive impairment, while Calero’s study also found that depression is a predictive factor for cognitive decline in older adults27,28. In summary, the hypothesis is proposed that there is a mediating role for anxiety and depression between leisure activity and cognitive function.

Although several studies have confirmed the association between leisure activities and cognitive function, there is little research that integrates individual evaluation, anxiety, and depression to look into their mediation effects. Furthermore, this survey incorporates life satisfaction and health satisfaction into individual evaluation.

Research methods and design

Research design

This study used data from the Chinese Longitudinal Healthy Longevity Survey (CLHLS2017-2018), a tracking survey of older adults in China organized by the Center for Healthy Aging and Development Studies (CHADS) at Peking University. The baseline survey was conducted in 1998, and there are also data from seven surveys in 2000, 2002, 2005, 2008–2009, 2011–2012, 2014, and 2017–2018. We excluded participants who were under the age of 65, had missing key variables (missing cognitive functioning scores, incomplete information on variables related to leisure activities, individual evaluations, anxiety, depression, etc.), or had extreme values (unrealistic maximums or minimums, such as 33 years of education). Finally, we chose 11,101 persons as our study sample. This sample’s broad representativeness assures that our research findings are applicable to a larger population.

Measurement

Dependent variable

Cognitive function: Participants’ cognitive function was assessed using the Chinese version of the Mini-Mental State Examination (MMSE), with scores ranging from 0 to 30. The scale consists of 24 questions divided into 5 dimensions: orientation, memory, attention and calculation, language, and and visual construction29. After adjusting for educational levels, MMSE scores of 19 or less, 21 or less, and 25 or less were deemed markers of cognitive impairment in persons with no previous education, less than 6 years of education, and more than 6 years of education, respectively30.

Independent variable

Leisure activities: Reference to previous studies and questionnaire content13, we utilized a comprehensive evaluation comprising seven questions, covering physical and mental activities, to measure participants’ level of leisure activities.The following seven questions were assigned points for their responses: (1) Do you do housework now? (2) Do you do tai chi now? (3) Do you do square dancing now? (4) Do you grow flowers and keep pets now? (5) Do you read books and newspapers now? (6) Do you keep poultry and livestock now? (7) Do you watch TV and listen to the radio now. Here is how the five responses were scored: almost every day = 3; not every day, but at least once a week = 2; not every week, but at least once a month = 1; not every month, but sometimes = 1; do not participate = 0, add up the points for all seven questions, higher scores indicate more active leisure activities.

Mediating variable

Individual evaluation: Refer to the World Health Organization WHOQOL-BREF Quality of Life Assessment, participants’ individual evaluations of life and health were combined to provide a score evaluation, allowing for a more comprehensive understanding of their subjective state31. The following two questions were assigned points for their responses: (1) How do you feel about your life now? (2) How do you feel about your own health now? Here is how the 5 responses are scored: very good = 3, good = 2, fair = 1, bad or very bad = 0, add up the points for all two questions, with higher scores indicating higher individual evaluation.

Anxiety: The Generalized Anxiety Disorder Scale (GAD-7) was used to evaluate participants’ anxiety levels, considering the potential impact of anxiety on cognitive function. Scores ranged from 0 to 21, with higher scores indicating greater anxiety32,33.

Depression: We assessed participants’ depression using the Center for Epidemiologic Studies Depression Scale (CES-D), recognizing the potential influence of depression on cognitive function. The study defined a cumulative score of ≥ 10 as indicative of depressive symptoms, based on Anderese et al.34.

Covariates

In addition to focusing on core variables, we collected a range of demographic variables, including age, gender, years of education, place of residence, marital status, and living arrangements, and used them as covariates to control for potential confounding factors.

Research method

In this study, IBM SPSS Statistics version 25 was used to complete all the data analysis and processing. We initially provided a detailed description of the sample’s basic characteristics using descriptive statistical methods and explored the relationships between variables using Pearson correlation analysis. Pearson correlation analysis is to reflect the degree of linear correlation between two random variables, taking values ranging from − 1 to 1. The closer the absolute value of r is to 1, the stronger the correlation, and the correlation analysis is used as the basis analysis for many mediation mechanism studies, demonstrating the reliability of the methodology35. Subsequently, performed Bootstrap processing (5000 times) used SPSS macro PROCESS program (Model 81) designed by Hayes to investigate the mediating effects of individual evaluation, anxiety, and depression in the relationship between leisure activities and cognitive function. We set the significance level at p < 0.05 to ensure the reliability and validity of the results12,13,36. If zero was not included in the interval of 95% CI, it indicated that the mediating effect was significant.

Through these in-depth analytical approaches, we aim to comprehensively understand the associations between leisure activities and cognitive function and uncover the underlying mediating mechanisms, thereby providing more detailed and compelling data support for related research fields.

Results

Characteristics of samples

The results of a demographic study on 11,101 elderly individuals are as follows: the average age of the elderly sample is 84.24 years with a standard deviation of 11.56 years, indicating a wide age range within the sample. In terms of gender composition, females account for 55.7%, slightly more than males (44.3%). Educational levels indicate that 46.9% of the elderly population are illiterate, 33.3% received primary education, while only 19.8% received education at or above junior high school level, reflecting inadequate educational resources in rural areas. The majority of the elderly (75.3%) reside in towns and villages, with a smaller percentage living in urban areas (24.7%), potentially impacting healthcare and elderly care service needs. Marital status shows that 57.5% are unmarried, while 42.5% are married. Additionally, 80.6% of the elderly live with family, 16% live alone, and 3.4% reside in nursing homes. Regarding mental health, 53% of the elderly do not exhibit depressive symptoms, while 47% experience depressive symptoms. The average cognitive function score is 24.63, indicating that the majority of the elderly (70.1%) do not have cognitive impairments, but 29.9% do exhibit cognitive decline., as shown in Table 1.

Table 1 Characteristics of the older adults (n = 11,101).
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Correlation analysis

The analysis results indicate that in the surveyed sample, leisure activities are positively correlated with individual evaluation (r = 0.130, p < 0.01) and cognitive function (r = 0.485, p < 0.01), suggesting that positive leisure activities may help maintain or improve individual evaluation and cognitive function levels. Furthermore, leisure activities are negatively correlated with anxiety (r=−0.078, p < 0.01) and depression (r=−0.207, p < 0.01), indicating that positive leisure activities may contribute to reducing anxiety and depression levels.

Individual evaluation is positively correlated with cognitive function (r = 0.162, p < 0.01) and negatively correlated with anxiety (r=−0.279, p < 0.01) and depression (r=−0.452, p < 0.01). Additionally, anxiety is negatively correlated with cognitive function (r=−0.128, p < 0.01), and depression is also negatively correlated with cognitive function (r=−0.208, p < 0.01). The significant negative correlation between anxiety, depression, and cognitive function suggests that mental health issues may be associated with decreased cognitive function, as shown in Table 2.

Table 2 Correlations between leisure activity, individual evaluation, anxiety, depression, and cognitive function.
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Mediation analysis of individual evaluation, anxiety and depression

On the basis of controlling for age, gender, place of residence, years of education, and marital status, this study conducted a multiple mediation model regression analysis with leisure activity as the independent variable, cognitive function as the dependent variable, and individual evaluation, anxiety, and depression as mediating variables.

The results of path analysis showed that the indirect effect of the path mediated by individual evaluation was 0.0269 (95% CI= [0.0209, 0.0334]), the indirect effect of the path mediated by anxiety was 0.0036 (95% CI= [0.0014, 0.0064]), the indirect effect of the path mediated by depression was 0.0061 (95% CI= [0.0026, 0.0099]), and the indirect effect of the path mediated by individual evaluation and anxiety was 0.0041 (95% CI= [0.0024, 0.0058]), The indirect effect of the pathway mediated by individual evaluation and depression is 0.0039 (95% CI= [0.0017, 0.0062]), so the total indirect effect is 0.0446 (95% CI= [0.0372, 0.0527]), the direct effect is 0.3780 (95% CI= [0.3459, 0.4101]), and the total effect is 0.4226 (95% CI= [0.3905, 0.4548]). The mediating effect of each pathway is significant, and the chain mediating effect of individual evaluation and anxiety, and individual evaluation and depression is also established, They play a partial mediating role in the impact of leisure activities on cognitive function, as shown in Table 3; Fig. 1 .

Table 3 Significance tests for mediating effects.
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Fig. 1
figure 1

The outcome model of the effect. *** p < 0.001 (two-tailed).

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Discussion

The direct effect of leisure activity on cognitive function

The results indicate that there is a positive correlation between leisure activities and cognitive function among elderly people in China, which is consistent with previous studies37,38,39. Cognitive dysfunction refers to a decline in memory, responsiveness, or other cognitive abilities, and severe cognitive impairment may progress to dementia40. Firstly, engaging in active leisure activities like reading, card gmes, and Tai Chi gives the aged brain extra workout and stimulus. By increasing their knowledge reserves, increased thought and brain activity help to prevent cognitive decline and preserve normal cognitive performance41,42. Secondly, Leisure activities are inherently fun experiences in which participants are able to experience pleasure while achieving learning and communication effects that are beneficial to cognitive function43.

The mediation effect of individual evaluation、anxiety and depression

Our study tried to reveal the potential mechanism between leisure activity and cognitive function among Chinese older adults.We demonstrated the indirect effect between leisure activity and cognitive function in Chinese older adults can be mediated by individual evaluation, anxiety and depression.

Firstly, this individual evaluation indicator in the current study is based on older people’s perceptions of their health and quality of life. Chinese people, influenced by ancient feudalism, are exceedingly self-respecting and adept at saving face, and they are very concerned about how they are perceived. Self-esteem is an appraisal of one’s subjective value, a positive or negative attitude toward oneself44, and it’s the individual evaluation in this study. Self-esteem was shown as a significant predictor of subjective well-being and life satisfaction45. It can be said that people with higher quality of life tend to have higher individual evaluations. Research confirms that active leisure activities are good for the health of older, and Christine et al. found that leisure activities were effective in inhibiting impairments in activities of daily living19. In addition, higher participation in leisure activities tends to be associated with a higher quality of life46, equivalent to better individual evaluation. Moreover, research has also confirmed the positive effects of better life satisfaction and health self evaluation, equivalent to a good individual evaluation in reducing anxiety and depression, thereby promoting cognitive function20.

Secondly, results indicated that the elderly who participated more leisure activity were less likely to feel anxiety or depression, which in turn prevented their cognitive decline13. Based on the results from previous studies, more frequent engagement in leisure activity was associated with a better mental health47,48. For example, one study found that more leisure time tended to be associated with lower rates of anxiety and depression49. Anxiety is often accompanied by nervousness, while depression often manifests itself as a low mood. Anxiety is a recurring problem among older adults, and people with anxiety disorders have control and attention deficits and impaired memory, leading to cognitive decline50. Depression linked to mild cognitive impairment and maybe a faster progression of cognitive decline51. Participation in leisure activities develops social connections and increases social participation, which benefits the mental health of older persons and in turn protects their cognitive function52.

The serial multiple mediation model

Finally, in addition to examining the independent mediating role of individual evaluation、anxiety and depression, we also tested whether there is a chain mediating role between leisure activity and cognitive function. The results of the present study demonstrated that leisure activity first had a positive correlation with individual evaluation and then reduced anxiety, which was in turn related to slow down the decline of cognitive function. Research confirms that leisure activities bring older adults better satisfaction with life and health, higher expectations, which in this study is called individual evaluation, thus inhibiting the emergence of anxiety, which in turn protects cognitive function52,53. Leisure activities can release the physical and mental stress of the elderly, while social exchanges are also conducive to the development of a good mindset among the elderly54. So in the same way, leisure activity first had a positive correlation with individual evaluation and then reduced depression, which was suppressed cognitive decline. A previous study found specific leisure activity participation was a significant correlate of higher levels of satisfaction with life and lower levels of depression47. Studies have shown that high life satisfaction in people with hypertension suppresses anxiety and depression55, and studies in women have found associations between life satisfaction and anxiety and depression56, and studies in military personnel have shown that people with high health satisfaction have less anxiety and depression57. Regardless of the group, at least we have found a role for individual satisfaction, and by analogy with the older adults, it can also be said that individual evaluation has an association with anxiety and depression.Many studies also have confirmed the correlation between anxiety and depression and poorer cognitive function, and anxiety and depression may have an interactive effect, while also causing varying degrees of damage to cognition and the brain58,59.

In summary, through these analyses, our study found that not only are individual evaluation, anxiety, and depression each associated with cognitive function, they also play a partially mediating role in the relationship between leisure activities and cognitive function. Higher individual evaluations reduce anxiety about the future, thereby suppressing anxiety and depression, and indirectly protecting the cognitive function of the elderly.

Limitations

This research had three main shortcomings. Firstly, the study’s cross-sectional design made it impossible to determine a cause-and-effect relationship between the factors it examined. Furthermore, the utilization of individual-reported questionnaire data raised the possibility of recall bias. Finally, the fact that the individual evaluation variable was created purely from the content of the questionnaire suggests that additional thorough and empirically supported measurements are required to confirm these results. More thorough and rigorous studies should be the main emphasis of future research projects in order to determine how these variables interact.

Conclusion

This study found that individual evaluation and anxiety, depression, they plays a mediating role in the association between leisure activity and cognitive function in older adults in China. Despite the shortcomings of our study, it also has certain guiding significance for the problems existing in older adults daily life. Based on the results of our study, The government should give the elderly more opportunities to participate in leisure activities, such as planning age-appropriate recreational facilities, furthermore, pay attention to the physical and mental health of the elderly, so as to improve their life expectancy and sense of well-being, and to reduce anxiety and depression among them.