Unexpected Weight Loss In Older Adults Could Be A Sign Of High Risk Dementia Onset

Weight loss is usually considered a good thing, unexpected and extreme weight loss can be a sign of something in your body going very wrong. There could be some underlying issues that are causing your body to pull weight and nutrition from your muscles and body fat to keep you going. As you grow old, your limbs grow weaker, and same for your muscles, so you do lose some weight as you age, but losing a lot of it too quickly could be a sign of something much worse, Dementia. A recent study published in JAMA Network Open 2025 Cardiometabolic Trajectories Preceding Dementia in Community-Dwelling Older Individuals, has identified potential early indicators of dementia, including significant weight loss and specific digestive changes, appearing years before noticeable cognitive decline.

The study showed that people who later got dementia had their Body Mass Index, or BMI, go down faster than those who stayed healthy. BMI is a way to see if someone's weight is healthy for their height. This drop in BMI started happening many years before they were told they had dementia, sometimes as early as 11 years ago. Also, these people often started with a lower BMI to begin with. So, even though everyone's weight might change a little as they get older, the people who developed dementia had a much bigger and faster weight loss.

What Are Some Other Indicators Of Dementia?

Along with their BMI, the size of their waist also changed. People who ended up with dementia had smaller waist sizes, and this difference was noticeable about 10 years before they were diagnosed. This means that their bodies were changing in ways that showed up long before they or their doctors noticed any problems. So, not only was there weight loss, but also a loss of abdominal fat. This measurement is important because fat around the waist can be related to other health issues.

The study also found changes in their blood. Specifically, the "good" cholesterol, called HDL, went up in people who developed dementia. This increase happened about five years before they were diagnosed. It's tricky because HDL is usually seen as a good thing for your heart. But in this case, it seems like it might be a sign of changes happening in the brain. Scientists are still trying to understand why this happens.

Weight Loss Doesn’t Cause Dementia, Dementia Causes Weight Loss

When we see that people with dementia lose weight, it's easy to think that the weight loss is what caused dementia. But experts think it's the other way around. They call this "reverse causation." This means that the brain changes that cause dementia also cause people to lose weight. The brain changes can affect things like appetite, how the body uses food, and how people go about their daily lives. For example, people might forget to eat, have trouble making meals, or move around less.

While the study revealed a lot about different indicators of dementia and bodily changes, there are many limitations to the study. Everyone loses some weight as they get older. So, it's hard to know when weight loss is just a normal part of aging and when it's a sign of dementia. The study found that people with dementia lost weight faster, but it's still tricky to tell the difference in everyday life. Doctors need to look at other things, like memory tests, to figure out if someone's weight loss is a cause for concern.

If someone is losing weight without trying, and they're also having problems with their memory or thinking, it's important to talk to a doctor. It's not just about the weight loss; it's about the whole picture.