Skeletal muscle function and need for long-term care of urban elderly people in Japan (the Bunkyo Health Study): a prospective cohort study

Abstract

PurposeThe proportion of elderly individuals (age ≥65 years) in Japan reached 27.7% in 2017, the highest in the world. A serious social problem in a super-aged society is the rise in the number of elderly people who need long-term care (LTC), which is mainly due to cerebrovascular disease, dementia, age-related frailty, falls and fractures, and joint disease. We hypothesised that decreased muscle mass, muscle strength and insulin sensitivity are the common risk factors for these diseases related to needing LTC. We developed a prospective cohort study of elderly subjects in an urban community to test this hypothesis. The primary objective is to prospectively investigate associations between muscle mass, muscle strength, and insulin sensitivity and incidence of main disease and risk factors of needing LTC. The primary outcomes are the incidence of cerebrovascular disease and cognitive decline.ParticipantsParticipants were 1629 people aged 65–84 years living in 13 communities in an urban area (Bunkyo-ku, Tokyo, Japan). Average age was 73.1±5.4 years.Findings to dateWe obtained baseline data on cognitive function, cerebral small vessel disease (SVD) determined by brain MRI, body composition, bone mineral density, arteriosclerosis, physical function, muscle mass, muscle strength and insulin sensitivity. Mild cognitive impairment and dementia were observed in 18.1% and 3.3% of participants, respectively. The prevalence of cerebral SVD was 24.8%. These characteristics are similar to those previously reported in elderly Japanese subjects.Future plansWe will ask participants about their health status, including incidence of cerebrovascular disease, falls, fractures and other diseases every year by mail. We plan to re-evaluate cognitive function, brain MRI parameters and other parameters at 5 and 10 years after the baseline evaluation. We will evaluate whether low muscle function (muscle mass, muscle strength or insulin sensitivity) is a risk factor for cognitive decline or cerebrovascular disease.

Age-Related Changes in Relaxation Times, Proton Density, Myelin, and Tissue Volumes in Adult Brain Analyzed by 2-Dimensional Quantitative Synthetic Magnetic Resonance Imaging

“…Subjects 65 years or older were recruited as part of the Bunkyo Health Study lasting over 10 years that included 1629 older people aimed at the prevention of disease requiring long-term care. 43 Subjects recruited from April 2017 until September 2018 in the Bunkyo Health Study were included in the current study. We classified white matter (WM) hyperintensity on fluid-attenuated inversion recovery (FLAIR) imaging using the Fazekas scale 44 and excluded subjects with a scale score of 3 or higher.…”

Insulin resistance and muscle weakness are synergistic risk factors for silent lacunar infarcts: the Bunkyo Health Study

“…The Bunkyo Health Study is a prospective cohort study designed to clarify how muscle mass, muscle strength, and insulin sensitivity are associated with multiple diseases that necessitate long-term care 38 . In this study, we recruited elderly subjects aged 65–84 years living in Bunkyo-ku, an urban area in Tokyo, Japan.…”

An Investigation of Water Diffusivity Changes along the Perivascular Space in Elderly Subjects with Hypertension

“…The Bunkyo Health Study is a prospective cohort study that has been running for .10 years. 16 We recruited elderly subjects 65-84 years of age who were living in Bunkyo-ku, an urban area in Tokyo. Our cohort comprised 1629 elderly people.…”