Our objective was to determine whether the consumption of green tea, coffee, or black tea influences the incidence of dementia and mild cognitive impairment (MCI) in older people. We conducted a population-based prospective study with Japanese residents aged >60 years from Nakajima, Japan (the Nakajima Project). Participants received an evaluation of cognitive function and blood tests. The consumption of green tea, coffee, and black tea was also evaluated at baseline. Of 723 participants with normal cognitive function at a baseline survey (2007–2008), 490 completed the follow up survey in 2011–2013. The incidence of dementia during the follow-up period (mean ± SD: 4.9±0.9 years) was 5.3%, and that of MCI was 13.1%. The multiple-adjusted odds ratio for the incidence of overall cognitive decline (dementia or MCI) was 0.32 (95% CI: 0.16–0.64) among individuals who consumed green tea every day and 0.47 (95% CI: 0.25–0.86) among those who consumed green tea 1–6 days per week compared with individuals who did not consume green tea at all. The multiple-adjusted odds ratio for the incidence of dementia was 0.26 (95% CI: 0.06–1.06) among individuals who consumed green tea every day compared with those who did not consume green tea at all. No association was found between coffee or black tea consumption and the incidence of dementia or MCI. Our results indicate that green tea consumption is significantly associated with reduced risk of cognitive decline, even after adjustment for possible confounding factors.

Background: An increasing elderly population in Japan requires effective cognitive intervention programs for dementia. This study demonstrates the effectiveness of such programs for older adults. Methods: The participants were local community-dwelling non-demented older adults and adults with mild cognitive impairment who underwent executive function and group aerobic training. In addition, a non-intervention group participated in activity sessions involving handicraft, Skutt ball matches, and cooking. The four criteria for assessment were cognitive function, instrumental activities of daily living, human relationships, and physical function. Results: The participants in both intervention groups showed a significant improvement in their memory function compared with the non-intervention group. Conclusion: Early rehabilitation intervention using executive function and aerobic training programs may improve memory.

ObjectiveWe aimed to evaluate a foot-care awareness program designed to improve foot morphology, physical functioning, and fall prevention among the community-dwelling elderly. Eleven independent community-dwelling elderly women (aged 61–83 years) were provided with foot-care advice and shown effective foot-care techniques to perform regularly for 6 months, and compared with a control group of 10 elderly women who did not receive any intervention. Measurements of foot form, functional capacity, subjective foot movement, and physical function were taken at baseline and 6-month follow-up.ResultsAt follow-up, improvements were seen in the intervention group in foot morphology, subjective foot movement, foot pressure, and balance. In the intervention group, 90% of women had maintained or improved foot form and none of them had fallen during the post-intervention period, compared to the control group where 30% improved foot form (p = 0.0075) and four (40%) of them had fallen. Therefore, a foot-care program may have the potential to prevent falls and improve mobility among the elderly. Trial Registration UMIN-CTR No. UMIN000029632. Date of Registration: October 19, 2017Electronic supplementary materialThe online version of this article (10.1186/s13104-017-2898-9) contains supplementary material, which is available to authorized users.

Significant differences exist in demographic characteristics between responders and non-responders in population-based studies on mental health and cognitive status, but much less is known regarding differences in the prevalence of dementia and cognitive dysfunction between them. Here we compared the prevalence of dementia and mild cognitive impairment between early responders of a mass brain function examination and delayed responders (non-responders of the mass brain function examination) in a survey of elderly Japanese citizens (≥65 years) to evaluate non-responder bias. All residents in an area of Nakajima, Japan, were considered as potential candidates (n = 783). Participants of a mass brain function examination were considered as "early responders." The cognitive functions of delayed responders were assessed by home visits. To assess the correlation between sociodemographic characteristics and cognitive functions, the early and delayed responders completed the same questionnaires and neuropsychological tests. Delayed responders (n = 320) were significantly older and less educated than the early responders (n = 307). The delayed responders also exhibited a higher frequency of dementia and mild cognitive impairment than the early responders, even when the groups were restricted to the age group 65-89 years. Our results suggest that population-based studies likely underestimate the prevalence of dementia and mild cognitive impairment, especially if the participation rate is low.

Our results demonstrate significant beneficial effects of vitamins C and E in reducing the risk of cognitive decline in women with APOE E4 and men without APOE E4, respectively.