Photo/Illutration Elderly people raise their arms straight in an exercise to prevent physical frailty in Minami, Tokushima Prefecture, in December 2022. (Asahi Shimbun file photo)

Being obese may lead to a lower likelihood of death among elderly people with deteriorated mental and physical conditions called frailty, a team of researchers has found.

Those free from the age-associated frailty are at the least risk of mortality when they are a little overweight, the team reported.

The findings were announced by scientists from Waseda University, the National Institutes of Biomedical Innovation, Health and Nutrition, Biwako Seikei Sport College and Kyoto University of Advanced Science.

“Though elderly individuals are believed to less likely die if they are moderately overweight, the situation can be different, depending on whether they have frailty,” said Daiki Watanabe, an assistant professor of nutritional epidemiology at Waseda University, who was part of the research team.

“While being extremely thin may keep elderly people from living longer lives, it is true at the same time that being fatter does not necessarily ensure a longer life.”

The term “frailty” refers to an intermediate stage between the states of health and illness. This condition draws particular attention, as proper health management is important to stop nursing care from becoming necessary.

The team examined the health conditions, lifestyles and other factors of 10,912 residents who were 65 or older in Kameoka, Kyoto Prefecture. Their average age was 74.

Whether they have frailty was determined based on the 25-item checklist developed by the Ministry of Health, Labor and Welfare. A total of 4,763 were identified as frail because they met seven or more prerequisites.

Follow-up surveys whose median length was 5.3 years showed that 1,352 of the subjects had passed away, and the team examined how the fatality risk was influenced by their body mass index (BMI).

BMI is obtained by dividing weight expressed in kilograms by height expressed in meters, then dividing the result by the height again.

Levels of less than 18.5 mean people are “underweight,” while the figures of 18.5 through 24.9 are for those with normal weight. Showing 25 or higher readings indicate “overweight.”

The findings of the researchers’ analysis revealed that elderly individuals stricken by frailty can die more easily when they have lower BMI values. A 1-point increase in BMI contributes to a 9-percent decline in the mortality rate.

Still, frailty proved to be risky by itself. Elderly people with frailty were 1.43 times to 3.63 times more likely to die, compared with their healthy counterparts marked by BMI readings of 21.5 through 24.9.

Even among older people free of frailty, lower BMI values were apt to contribute to the higher possibility of death.

Those falling into the underweight category were at 1.89 times the risk of dying than people characterized by the 21.5-24.9 BMI window. The mortality rate was down 15 percent for each additional point up to 23.

It should be noted that the readings of 23 or higher were no longer helpful in lessening the likelihood of death anymore.

Any figures outside the BMI range of 23 to 24, regardless of whether being obese or underweight, led to a higher fatality risk, according to the outcome of an even closer analysis.

The lowest possibility of death among all surveyed individuals was reported for the group of non-frail people with BMI levels 23 through 24.

The BMI values of 23 to 24 are applied to 160-centimeter-tall people weighing around 60 kg. If they are 170 cm or 180 cm tall, their weight should be around 68 kg or 76 kg, respectively.

Watanabe stressed that staving off frailty is most important above all else.

“What is important is reviewing lifestyles such as doing physical activities daily, maintaining well-rounded diets and actively socializing with others, while other measures can differ given individuals’ differing circumstances,” he said.

The team’s results have been published in the specialized journal Clinical Nutrition at (https://doi.org/10.1016/j.clnu.2024.01.002).

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