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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. [ABSTRACT FROM AUTHOR]

Aims: Vulnerable older adults tend to decrease physical activity (PA) and increase sedentary time (ST). Previous research on the associations between ST and brain volume have yielded inconsistent findings, without considering the impact of cognitive engagement (CE) on cognitive function. We aimed to examine the association between ST with CE and brain volume. Methods: A structural magnetic resonance imaging survey was conducted among community‐dwelling vulnerable older adults. Brain volumetric measurements were obtained using 3T magnetic resonance imaging and pre‐processed using FreeSurfer. ST with low or high CE was assessed using a 12‐item questionnaire. PA was assessed by the frequency of light and moderate levels of physical exercise according to the Japanese version of the Cardiovascular Health Study criteria. Participants were categorized into a low PA group and a moderate‐to‐high PA group. Results: Among 91 participants (83.1 ± 5.2 years old, 61.5% female), 26 were low PA. The overall sample and moderate‐to‐high PA group did not show significant positive associations with brain volume for ST with high CE. In the low PA group, isotemporal substitution models showed that replacing ST with low CE by ST with high CE was significantly associated with increased brain volume in some areas, including the rostral and caudal anterior cingulate (β = 0.486–0.618, all P < 0.05, adjusted R2 = 0.344–0.663). Conclusions: Our findings suggest that replacing ST with low CE by ST with high CE is positively associated with brain volume in vulnerable older adults with low PA. Geriatr Gerontol Int 2024; 24: 82–89. [ABSTRACT FROM AUTHOR]

Aim: The present study aimed to examine whether dietary diversity is associated with cognitive impairment, including mild cognitive impairment (MCI), in community‐dwelling older Japanese adults. Methods: This cross‐sectional study was carried out in a general community setting. MCI and global cognitive impairment (GCI) were assessed using the Mini‐Mental State Examination and National Center for Geriatrics and Gerontology‐Functional Assessment Tool, which are multicomponent neurocognitive tests that include memory attention, executive function and processing speed. Dietary diversity was assessed using the diet variety score. The diet variety score assessed the 1‐week consumption frequency of 10 food groups, and either 0 or 1 point was allocated to each category based on the following responses: (i) "eat almost every day" (1 point); and (ii) "not eaten almost daily" (0 points). Older adults with a diet variety score of ≥3 points were defined as having high dietary diversity. Results: Data included 8987 older adults (mean age 73.9 ± 5.5 years; men 44.3%). The overall prevalences of MCI and GCI were 17.1% (n = 1538) and 8.4% (n = 753), respectively. The proportion of patients with a high dietary diversity was 69.9% (n = 6286). Multinomial logistic regression analysis revealed high dietary diversity was associated with MCI (OR 0.83, 95% CI 0.73–0.94) and GCI (OR 0.77, 95% CI 0.65–0.92) after adjusting for covariates. Conclusions: This study had a large sample size of older Japanese adults, and showed that high dietary diversity was associated with a lower proportion of MCI and GCI among older adults. Geriatr Gerontol Int 2024; 24: 75–81. [ABSTRACT FROM AUTHOR]

Background: This study aimed to examine whether physical activity measured using the International Physical Activity Questionnaire Short Form (IPAQ-SF) can predict incident disability in Japanese older adults. Methods: Community-dwelling older adults participated in a prospective cohort survey. The time spent in moderate- to vigorous-intensity physical activity was assessed at the survey baseline using the IPAQ-SF. The participants were categorized into those who spent ≥150 minutes per week (physically active) or <150 minutes per week (physically inactive) in moderate- to vigorous-intensity physical activity. Incident disability was monitored through Long-Term Care Insurance certification during a follow-up lasting 5 years. Results: Among the 4387 analyzable participants (mean age = 75.8 y, 53.5% female), the IPAQ-SF grouped 1577 (35.9%) and 2810 (64.1%) participants as those who were physically active and inactive, respectively. A log-rank test showed a significantly higher incidence of disability among the inactive group of participants (P <.001). The Cox proportional hazards model showed that physically inactive participants had a higher risk of incident disability than the physically active ones did, even after adjusting for covariates (hazard ratio, 1.24; 95% CI, 1.07–1.45, P <.001). Conclusions: Older adults identified as physically inactive using the IPAQ-SF had a greater risk of developing disabilities than those identified as physically active. The IPAQ-SF seems to be appropriate to estimate the incidence risk of disability. [ABSTRACT FROM AUTHOR]