After adjusting for potential confounding variables, our study found that older adults who participated in leisure activities were significantly associated with better cognitive function. Productive activities in this study were defined as doing housework, which included meal preparation, medication management, shopping and handling finances. All of these things could improve memory and thinking abilities, which contribute to improving older adults’ cognitive function [14]. Participation in physical activities was positively associated with older adults’ quality of life, life satisfaction, and self-efficacy, contributing to positive moods and cognitive function [15]. When reading newspapers and books, older adults think positively about comprehension, which stimulates and improves cognitive function effectively [16]. Watching TV or listening to the radio could act as a positive cognitive stimulus for older adults’ brains [17]. There are several possible explanations for the relationship between social activities and cognitive function. Social activity participation maintains or expands the social network of older adults. Studies have indicated that extensive social networks seem to protect against dementia [18]. Individuals with an expanded social network have more chances to access various forms of material resources or health-related information, which may have a positive impact on cognitive function [19]. Additionally, participation in social activities will open a door for older adults to acquire new learning as an effective intellectual stimulation [20].

Influenced by Chinese specific cultural practices or norms, some Chinese older adults always engaged in playing Tai Chi, kungfu and majiang, which might have specific beneficial effects on cognition at the behavioral and neuroelectric levels [21]. Regarding the differences across gender, our study found that males enjoyed extra benefits from recreational activities compared with females. Females enjoyed extra benefits from productive activities and social activities compared with males. Previous studies found that there were significant gender differences in leisure activity participation. One study found that women were more active than men within the domain of domestic activities, while men were more active than women in self-improvement [7]. In traditional Chinese culture, men often seek significance and identity through being esteemed in their work unit, whereas women tend to pay more attention to the internal family. This finding was also consistent with the Chinese cultural context and our study findings.

Regarding the differences across age groups, this study found that older age enjoyed extra benefits from productive, physical, intellectual, recreational and social activities in comparison with younger age. Compared to younger older adults, the oldest old adults were more likely to sustain multiple types of neuropathology, and this increased burden was associated with decreased cognitive function. Factors such as a higher prevalence of sensory deficits, frequent comorbidities leading to polypharmacy, and a higher prevalence of social isolation make the oldest old population a unique group, differing from elderly individuals under 80 years of age (“young older adults”) [22]. This also highlighted the importance of participation in leisure activities among the older adults in their senior years.

This study indicated that participation in leisure activities is important for improving cognitive function in the older adults. This study also found a significant dose-response association between participation in increased leisure activities and reduced risk of dementia. Thus, in order to improve cognitive function, the older adults should increase not only the amount of time they participate in leisure activities, but also the types of leisure activities they participate in. Compared with other types of leisure activities, it’s more important for male to participate in recreational activities, and for female to participate in productive activities and social activities. The community could tailor different leisure activities for elderly of different genders and ages, for instance, organized social activities for older women, low to moderate intensity leisure activities for the oldest old adults. The government could provide more resources and venues for the elderly to participate in different types of leisure activities, strengthening the supportive environment across the whole society to improve cognitive function of the older adults effectively.

The limitations of this study are as follows. Firstly, all items were self-reported, which may lead to biased results. There may also be some other confounding factors that were not considered in this study, such as living status (alone or not) and depression. Future studies could take these potential confounding variables into consideration. Secondly, cross-sectional studies could not examine causal relationship, in other words, the present cross-sectional design could not exclude the possibility that older adults with better cognitive function tend to participate in more leisure activities. However, the data used is the most recent CLHLS data available, which could best reflect the current status of leisure activity participation and cognitive function of the Chinese older adults. Additionally, using cross-sectional data from 2018 was sufficient for this study to detect statistically significant associations between leisure activities and cognitive function, to explore the interaction effects of gender or age and different types of leisure activities on cognitive function in Chinese older adults. If using multi-stage panel data, there may be changes in survey methodology, question wording, or response options over time that could introduce bias or make it difficult to compare results across years. Thirdly, data during or after the COVID-19 pandemic were not available for this study. According to previous studies, COVID-19 could affect the participation in leisure activities, especially reducing the participation in physical and social activities while increasing the participation in indoor productive activities, recreational activities and intellectual activities [23]. China has optimized and adjusted the COVID-19 response measures for nearly two years, the lifestyle and leisure activity participation patterns of the elderly in China have been more similar to those before the COVID-19 pandemic. Based on this, the data of 2018 could reflect the current situation to a large extent. Due to no updated data available after the COVID-19 pandemic, we could not compare the differences before and after the COVID-19 pandemic in this study. Future studies can further explore the impact of the COVID-19 pandemic on the basis of this study.

The database used in this study, the Chinese Longitudinal Healthy Longevity Survey (CLHLS), is the earliest and longest-lasting social science survey in China, which makes the findings in this study more convincing. Although there are some limitations, our study is a large representativeness sampling study to decipher the relationship between leisure activity participation and cognitive function, which varies across activity types, gender and the age of the older Chinese population. This study found the significant positive association between five different types of leisure activities and cognitive function among older Chinese adults. The interaction between gender or age and different types of leisure activities on cognitive function in Chinese older adults was statistically significant. Future studies could expand the study population to the older adults in other countries, further explore the interaction effects of cultural backgrounds and different types of leisure activities on cognitive function in older adults across the world on the basis of this study.