In recent years, a trend known as “Oshi-katsu” has become popular in Japan. “Oshi-katsu” refers to all activities involving supporting or stanning a person of interest (such as an idol, anime character, athlete, or artist), with “Oshi” refers to a fanʼs favorite. The purpose of this study was to examine the relationship between “Oshi-katsu”, sports fan activities and mental health. The subjects were 1,752 people (average age＝37.99 ± 16.19 years) obtained through an online survey company. As a result of multiple comparisons, the sense of happiness was highest in sports fans compared to the other groups, the sense of depression was highest in the Oshi-katsu group compared to the other groups, and the sense of authenticity was lowest in the non-fan group compared to the other groups. Next, as a result of exploratory factor analysis, the 28 items of the original “Oshi-katsu scale” were interpreted as a six-factor structure (life enrichment through Oshi-katsu, aversion toward same Oshi fans, overdependence on Oshi, overinvestment in Oshi-katsu, fulfillment through Oshi-katsu friendships, emotional damage by Oshi’s hiatus) and had sufficient internal consistency. The results of an unpaired t-test showed that Oshi-katsu group had higher total scores on the Oshi-katsu scale than sports fans. Analysis using covariance structure modeling revealed that positive paths to feelings of depression were observed for “dependence on Oshi” and “emotional damage caused by the Oshi’s hiatus” from the Oshi-katsu scale, while negative paths were observed for “life enrichment by Oshi-katsu”, “over-investment in Oshi-katsu”, and “number of years of Oshi-katsu”.

　This report describes the community implementation of “Cogniit,” a multi-dimensional exercise program combining physical activity and cognitive stimulation designed to prevent the development of dementia in older adults. Conducted in July 2025 in Kariya City, Aichi Prefecture, in collaboration with the local government office, the program involved 37 participants aged 65 years and older. The program, which aimed to stimulate both physical and cognitive functions, involved alternating short sessions of stretching exercises, origami crafting, and balloon-based activities with inter-sessional breaks. Observations revealed a positive and cooperative atmosphere with frequent smiles and interactions among the participants. All participants completed the program with no adverse events, such as falls or physical distress, demonstrating high feasibility. Responses obtained via feedback questionnaires indicated that 97% of the participants enjoyed the program, suggesting that the program was favorably received by the local elderly. Instructional videos and staff support ensured inclusivity, thereby accommodating individuals with diverse cognitive and physical abilities. Combining lectures with hands-on activities facilitated knowledge retention and experiential learning, further contributing to participant motivation. This program suggests that “Cogniit” is a promising model for integrating dementia prevention through enhancement of social connections within community-based care systems. The results of this initial trial provide a practical basis for dementia prevention and social engagement in community-based care. The flexible design and supportive environment of this program contribute to the further development of health promotion for older adults.