A sharp drop in body weight among dementia patients may significantly increase their risk of death, according to a new study. In contrast, patients who maintained relatively stable weight or gained weight within an appropriate range showed a lower mortality risk.
A joint research team led by Professor Nam Ga-eun of the Department of Family Medicine at Korea University Guro Hospital, Professor Heo Yeon of the Department of Family Medicine at Seoul St. Mary's Hospital, and Professor Han Kyung-do of the Department of Statistics and Actuarial Science at Soongsil University announced the findings on Tuesday. The team used data from the National Health Insurance Service to identify approximately 37,000 dementia patients and tracked the association between body mass index (BMI) before and after dementia diagnosis and mortality risk over an average of 4.1 years.
According to the analysis, underweight patients after a dementia diagnosis had about a 1.6-fold higher risk of death compared with those of normal weight. The gap in mortality risk based on weight changes before and after diagnosis was also pronounced. Patients who shifted from obese to underweight showed the highest increase in mortality risk, at roughly twofold, while those who moved from normal or overweight to underweight also saw their mortality risk rise. In contrast, patients who maintained obesity or gained weight from normal or overweight to obese showed a relatively lower risk of death.
Dementia is a progressive disease linked to various health risks, including elevated mortality. While weight changes in older adults are known to be associated with deteriorating health, insufficient research has been conducted on how weight changes before and after a dementia diagnosis affect mortality. The findings suggest that weight loss itself may be a critical signal reflecting disease progression or declining nutritional status.
"Weight change is not simply a lifestyle issue but an indicator that reflects overall health status," Professor Nam said. "Especially after a dementia diagnosis, nutritional management and continuous monitoring are needed to prevent weight loss."
Weight loss in dementia patients can be linked to reduced food intake due to swallowing disorders, worsening cognitive function, and overall physical decline. These changes may also contribute to an increased risk of death.
"In subgroup analysis, the association between BMI changes and mortality risk was more pronounced in middle-aged patients than in older patients, and in the case of Alzheimer's disease, this phenomenon was even more evident in female patients," Professor Heo said. "This can be interpreted as the effect of differences in body composition and hormones, as well as vascular risk factors."
