The danger of being bedridden even if you are obese or thin

A study of about 7,200 elderly Japanese people found that the risk of "flail" (a state of physical and mental weakness), which is easily linked to the need for nursing care, increases in both people with low and high BMI, which indicates the degree of obesity. It became clear.

The relationship between flail and obesity in the elderly in Japan was unknown

In recent years, the word "Frailty" has been heard more and more. Frail is "a state in which the vulnerability to health disorders has increased due to various functional changes and a decrease in reserve capacity with aging." Specifically, weight loss, muscle weakness, fatigue, and walking speed. Indicates an increased risk of falls, depression, dementia, etc. due to decreased activity, decreased cognitive function, depressed mood, and social isolation.

The prevalence of flails increases with age. Since flails in the elderly are associated with an increased risk of death and disability (needing care), it is believed that a public health program is needed to prevent flails.

A study conducted in the United Kingdom showed that both people with low BMI and those with high BMI had high flails. However, because the mean and distribution of BMI differs between British and Japanese, it is not possible to apply such results directly to Japanese. Therefore, researchers such as the National Institute of Health and Nutrition are conducting BMI and flail prevalence among the elderly aged 65 and over who are participating in the prospective cohort study "Kameoka Study" conducted in Kyoto. I decided to investigate the relationship.

BMI = weight (kg) ÷ [height (m) x height (m)]

Underweight: less than 18.5

Normal weight: 18.5 or more and less than 25

Obesity: 25 or more and less than 35

Severe obesity: 35 and above

Of the 18,231 participants in the Kameoka study, 7,191 had all the information needed for this analysis. The average age was 73.4 years, with 52.7% of women and an average BMI of 22.7. BMI tended to be higher in men, hypertension, heart disease, diabetes, dyslipidemia, younger people, and nonsmokers. These people were stratified into the following 6 groups based on BMI: less than 18.5 (562), 18.5-19.9 (787), 20.0-22.4 (2195), 22.5-24.9 (2218) , 25.0-27.4 (1006 people), 27.5 or more (423 people).

Most of the elderly people targeted this time had a BMI of 30 or more, so 27.5 or more was analyzed as a group.

Two indicators, Fried et al.'S evaluation criteria (FP model, [Note 1]) and the Ministry of Health, Labor and Welfare's basic checklist (KCL, [Note 2]), were used to evaluate flail.

[Note 1] Fried et al.'S model: (1) Weight loss (2) Subjective fatigue (3) Decrease in activities of daily living (4) Decrease in physical ability (walking speed) (5) Decrease in muscle strength (grip strength) ――Of the 5 items, the case where 3 or more items are applicable is defined as flail.

[Note 2] Basic checklist of the Ministry of Health, Labor and Welfare: consists of 25 items. This time, if 7 or more items were applicable, it was flailed. "Manual for Life Function Evaluation for Care Prevention (Revised Edition)"

High prevalence of flails in both low and high BMI groups

When the prevalence of flails in each group was compared with reference to the BMI 22.5 to 24.9 groups, the prevalence of flails was high in the group with low BMI (less than 18.5 / 18.5-19.9) and the group with high BMI (27.5 or more). It became clear (Table 1).

When the relationship between the two is expressed with BMI on the horizontal axis and the odds ratio of flail on the vertical axis, the drawn curve is U-shaped in both the case of evaluation using FP and the case of evaluation using KCL. I did. Estimating based on these curves, the BMI with the lowest prevalence of flails was 24.7 to 25.7 with FP and 21.4 to 22.8 with KCL.

The results obtained this time suggest that it is necessary to evaluate the risk of flail and take preventive measures in both people with low and high BMI.