Adults aged 75 and older face a higher risk of death when their body weight fluctuates widely, according to a new study. Even when their first and last recorded weights were similar, those whose weight rose and fell sharply in between faced greater mortality risk — suggesting that long-term trends, not just current weight, deserve attention.
Seoul National University Hospital said on the 23rd that a research team led by professors Seo Ji-yeon and Choi Ji-min of the gastroenterology department at its Gangnam Center, together with professor Han Kyung-do of Soongsil University, reached the conclusion after analyzing health checkup data from 616,696 people aged 75 and older.
In old age, body weight can change easily because of illness, shifts in nutritional status or frailty. Previous research focused on how much weight was lost or gained over a set period, but this study examined how widely weight varied across multiple measurements. The aim was to capture health risks that cannot be detected from net weight change alone.
The team tracked deaths and causes of death through the end of 2022 among older adults whose weight was measured at least four times during health checkups from 2012 to 2015. The average age of participants was 78, and the median follow-up period was 7.5 years. A total of 195,585 participants died during that time.
Participants were divided into four groups by the degree of weight variability. Compared with the group with the smallest fluctuations, mortality risk was 12%, 26% and 62% higher in the other three groups, respectively. The figures were adjusted for age, sex, lifestyle habits, coexisting conditions and other factors affecting mortality risk.
Notably, among older adults whose first and last weights differed by less than 5%, those with large fluctuations in between still had a 41% higher risk of death. Among groups that ultimately lost or gained weight, those with wide swings showed 36% and 33% higher mortality risk, respectively. Large weight variability refers to older adults in the top 25% of fluctuation range among all participants.
The findings indicate that when assessing health in old age, the extent of fluctuation along the way matters as much as the net change in weight. Because illness, deteriorating nutrition and frailty can all alter body weight later in life, regular weight measurement and management are needed. The study was observational, however, and did not establish that weight fluctuation directly raises mortality risk.
"When the first and last weights are similar, it is easy to assume there was no significant change, but the shifts in between also need to be examined," professor Seo said. "Records of weight measured on multiple occasions can help assess the health status of older adults."
Professor Choi said: "For older adults whose weight changes substantially, it is worth paying attention to whether illness or changes in nutritional status lie behind it. It is important to measure weight regularly and review the trend during medical visits."
The findings were published in the international journal Scientific Reports.
