Monthly mortality from Alzheimer’s disease and other dementia in Japan

AbstractBackgroundThe aim of this study is to research seasonal changes in dementia mortality in Japan and to pursue the excess death on COVID‐19. COVID‐19 excess mortality were higher in homes providing nursing services to older people with dementia in England by Marciano, 2021. We have been researched the temperature‐mortality associations. The optimum temperature with the lowest mortality rate is the 84th percentile of the maximum temperature. We compared the changes in monthly mortality between 2019 and 2020, and examined whether there is an indirect effect on dementia associated with COVID‐19, considering the effects of temperature so far. For comparison, the total deaths of the elderly and accidental deaths such as falls were used.MethodFrom the monthly death from dementia (G30, Alzheimer disease, F01‐03, Vascular Dementia and Other) extracted from the vital statistics in Japan from 2019 to 2020, the dementia mortality rate by sex‐age group aged 65 and over was obtained. We estimated excess mortality using estimates from the optimal curves of monthly temperatures and monthly mortality rates for NCD since 2001, which the author has already announced.ResultSeasonal changes in dementia in 2019‐2020 were assessed to be consistent with estimates from optimal curves for monthly temperature and mortality. However, the 2020 mortality by gender‐age‐class based on 2019 increased sharply in June, August and October for ages 65‐69 and in October (10.2‐43.8 percent) for ages 70‐74. From May to August, falls and traffic accidents decreased, the total mortality of the elderly excluding accidents decreased during the same period, and the mortality of aged 70 and over increased by 8 percent after October. Discussion: The effect of COVID‐19 on dementia in 2020 could not be detected. Since the number of clusters of geriatric medical facilities in Japan has increased significantly since January 2021, long‐term inactivity of physical activity as a factor of immune function decline may increase the mortality from dementia. There are limits based on vital statistics.ConclusionExcess mortality from Dementia was undetectable in 2020, but an increased mortality was observed in certain age groups after the autumn.