This study examines the relationship between leisure activities and the risk of dementia in elderly individuals. The research involved 469 subjects aged 75 years or older who lived in the community and did not have dementia at baseline. Over a median follow-up period of 5.1 years, 124 subjects developed dementia, including 61 with Alzheimer's disease, 30 with vascular dementia, 25 with mixed dementia, and 8 with other types of dementia. The study found that participation in certain leisure activities, such as reading, playing board games, playing musical instruments, and dancing, was associated with a reduced risk of dementia. A one-point increase in the cognitive-activity score was significantly linked to a lower risk of dementia, while a one-point increase in the physical-activity score was not. The association between cognitive activities and dementia risk remained significant even after excluding subjects with possible preclinical dementia at baseline. The study also found that increased participation in cognitive activities was associated with a reduced rate of cognitive decline, particularly in memory. However, the protective effect of physical activities on dementia risk was not significant. The study suggests that participation in cognitive leisure activities may reduce the risk of dementia by improving cognitive reserve. However, the study acknowledges that observational data may not establish causality, and controlled trials are needed to confirm the protective effects of cognitive leisure activities on dementia risk. The study highlights the importance of cognitive activities in maintaining cognitive function and reducing the risk of dementia in the elderly.This study examines the relationship between leisure activities and the risk of dementia in elderly individuals. The research involved 469 subjects aged 75 years or older who lived in the community and did not have dementia at baseline. Over a median follow-up period of 5.1 years, 124 subjects developed dementia, including 61 with Alzheimer's disease, 30 with vascular dementia, 25 with mixed dementia, and 8 with other types of dementia. The study found that participation in certain leisure activities, such as reading, playing board games, playing musical instruments, and dancing, was associated with a reduced risk of dementia. A one-point increase in the cognitive-activity score was significantly linked to a lower risk of dementia, while a one-point increase in the physical-activity score was not. The association between cognitive activities and dementia risk remained significant even after excluding subjects with possible preclinical dementia at baseline. The study also found that increased participation in cognitive activities was associated with a reduced rate of cognitive decline, particularly in memory. However, the protective effect of physical activities on dementia risk was not significant. The study suggests that participation in cognitive leisure activities may reduce the risk of dementia by improving cognitive reserve. However, the study acknowledges that observational data may not establish causality, and controlled trials are needed to confirm the protective effects of cognitive leisure activities on dementia risk. The study highlights the importance of cognitive activities in maintaining cognitive function and reducing the risk of dementia in the elderly.