Unexplained Weight Loss May Be an Early Sign
Unintentional weight loss is often considered a normal part of aging, but new research suggests it may be an early warning sign of cognitive decline. A recent study found that older adults who experienced unexplained weight loss in their seventies were more likely to develop dementia compared to their peers with stable weight. These findings highlight the potential link between metabolism, brain health, and dementia risk.
Key Highlights:
- Older adults in their seventies who experienced unexplained weight loss had a higher likelihood of being diagnosed with dementia than those who maintained a stable weight.
- Researchers suggest that changes in metabolism, appetite, and mobility may indicate underlying neurodegenerative processes.
- Lower levels of high-density lipoprotein (HDL), commonly known as “good” cholesterol, were also associated with an increased risk of developing dementia.
This study underscores the importance of monitoring weight fluctuations in older adults, as they could serve as an early indicator of cognitive decline.
Signals for Dementia Risk
Aging brings many changes, some of which are expected, such as a gradual decline in muscle mass and metabolism. However, new research suggests that unexplained weight loss in older adults may be an early warning sign of dementia. The study, published in JAMA Network Open, highlights a potential link between neurodegeneration and metabolic changes that occur long before cognitive symptoms become evident.
Weight Loss as a Possible Early Indicator of Dementia
“While intentional weight loss can be beneficial for health, unintentional weight loss, especially in older adults, may reflect underlying neurodegeneration or other health conditions,” explains Zimu Wu, PhD, a research fellow at Monash University in Australia and the study’s lead author.
Brain changes associated with dementia can begin years before noticeable cognitive symptoms appear. These changes may affect metabolism, appetite, mobility, and daily function, leading to unexplained weight loss, Dr. Wu notes. “Rather than causing dementia, it may be an early warning sign of dementia,” he adds.
Adults Who Developed Dementia Experienced Faster Weight Loss
To investigate the connection between weight loss and dementia, researchers followed 5,390 cognitively healthy older adults for more than a decade. The participants were, on average, 77 years old at the beginning of the study and were monitored for key dementia risk factors, including body weight, waist circumference, blood pressure, and cholesterol levels.
Over the course of the study, 1,078 participants were diagnosed with dementia. The researchers found that those who eventually developed dementia had experienced more rapid declines in both body weight and waist circumference compared to their peers who remained cognitively healthy.
Interestingly, the study revealed that not only did dementia patients lose weight at a faster rate, but their waist circumference also shrank significantly more in the years leading up to their diagnosis. This suggests that changes in body composition may be an early indicator of cognitive decline.
Mika Kivimaki, PhD, an epidemiology professor at University College London who was not involved in the study, explains how these findings fit into existing knowledge about dementia risk. “Obesity in middle age is a known risk factor for dementia. However, lower weight in late life does not necessarily indicate protection against neurodegeneration if it results from unintended weight loss due to preclinical neurodegeneration,” Dr. Kivimaki says. “That said, maintaining a healthy weight in midlife is protective, as it reduces the risk of diabetes and vascular diseases, which are both known contributors to dementia.”
Cholesterol Levels Also Shift Before Dementia Diagnosis
Beyond weight loss, the study identified another potential early indicator of dementia: changes in cholesterol levels. Specifically, individuals with lower levels of high-density lipoprotein (HDL), often referred to as “good” cholesterol, were more likely to develop dementia. HDL cholesterol is known to help maintain cardiovascular health by keeping blood vessels free of harmful deposits, but its potential role in neurodegenerative diseases is still being explored.
Additionally, researchers noted that participants with lower blood pressure had a slightly increased likelihood of developing dementia. However, this connection was not statistically significant, meaning it could have been due to chance rather than a direct causal relationship.
Unexpected Findings Challenge Existing Assumptions
The study wasn’t designed to prove that weight loss or low HDL cholesterol directly cause dementia, nor did it investigate the specific mechanisms underlying these changes. However, the findings have raised questions among experts.
“The results of this study are surprising,” says Andrew Budson, MD, chief of cognitive behavioral neurology at the VA Boston Healthcare System and associate director of the Boston University Alzheimer’s Disease Research Center.
Dr. Budson points out that, based on existing research, lower body mass index (BMI), higher HDL cholesterol, and lower blood pressure are generally considered protective against dementia. “It’s possible that dementia patients in the study were losing weight and experiencing lower blood pressure because they were sick with some type of chronic illness,” he suggests.
“Many illnesses, including but not limited to infectious diseases, increase the risk of dementia,” Dr. Budson explains. “These are the only reasons that I can see as to why the results should have come out this way.”
How to Maintain Cognitive Health as You Age
While weight loss and metabolic changes may serve as early warning signs of dementia, there are proactive steps that older adults can take to support their cognitive health.
Dr. Wu emphasizes the importance of maintaining a balanced diet, staying physically active, engaging in social and intellectual activities, managing stress, and maintaining a positive outlook on life. These lifestyle factors are known to promote brain health and may help reduce the risk of cognitive decline.
The study findings also reinforce the importance of monitoring changes in weight, particularly if the loss is unexplained. “Unexpected weight loss may be an early sign of dementia, so it is important to seek medical advice if it occurs,” Dr. Wu advises.
By paying attention to these early signs and making healthy lifestyle choices, older adults and their families may be able to take proactive steps toward preserving brain function and overall well-being.