Elevated Risk of Dementia Diagnosis in Older Adults with Low Frequencies and Durations of Social Conversation

Abstract

Background: Social networks and social participation have protective effects on cognitive function maintenance and Alzheimer’s disease and general dementia development. Objective: We aimed to investigate the association between conversations and dementia incidence in older adults. Methods: This longitudinal prospective cohort study used population data from the National Center for Geriatric and Gerontology–Study of Geriatric Syndromes (NCGG–SGS) from September 2015 to February 2017. The database included 4,167 individuals in Japan aged ≥60 years who were generally healthy and without major cognitive impairment. Participants were classified into two groups according to six daily conversation measures at baseline. The conversation index was calculated as a composite score for these measures. Participants were tracked monthly over 60 months for new-onset dementia. Results: Data from 2,531 participants were analyzed (72.7±6.7 years; range: 60–96 years). Dementia incidence per 1,000 person-years was 15.7 (95% confidence interval, 13.6–18.1). The Youden index determined the cut-off point for dementia incidence, with a conversation index of 16/17 points. The low conversation group included more participants with new-onset dementia. Cox proportional hazards regression crude models showed remarkable relationships between dementia onset and specific conversation measurements, including conversation index. According to the Cox regression adjusted model, the cut-off point of the conversation index showed only a remarkable relationship with dementia onset. Conclusions: Dementia risk was extensively associated with low daily conversation statuses. The assessment of conversational factors may be useful as a risk indicator for the development of Alzheimer’s disease and general dementia.