For years researchers weren’t sure what to make of studies that showed people who were overweight in middle age were at a higher risk of developing Alzheimer’s disease, yet later in life a lower body mass index could be an early indicator of the disease.
Last week, the American Academy of Neurology published a study from Kansas University’s Alzheimer’s Disease Center that explored the connection between BMI and Alzheimer’s.
“We looked into it a little further to try to tease out why we see those sort of contradictions in literature,” said Jeffrey Burns, author of the study and co-director of KU Alzheimer’s Disease Center.
The study showed that the seemingly logical conclusion that people with early Alzheimer’s had a lower BMI because they weren’t remembering to eat wasn’t actually the case. Instead, Burns said the findings suggest that Alzheimer’s could be more than just a brain disease and affect the whole body, including metabolic change.
The study examined more than 500 people with advanced brain imaging techniques that can look for biomarkers for Alzheimer’s disease. Those biomarkers can be present in the brain years before the first symptoms appear.
The study found that people with Alzheimer’s biomarkers — both those with no memory or thinking problems and those with mild cognitive impairment — have a lower BMI than those who did not have the biomarkers.
“These people don’t have problems like forgetting to eat or putting a recipe together,” Burns said. “More is going on.”
Not enough is known yet to say whether Alzheimer’s disease affects areas of the brain that control caloric intake and metabolism or whether it involves a larger systemwide change in the body. But finding those answers could help develop strategies to intervene in and delay the disease.
“If we maintain our body weight through diet and increased calories, can we reduce the risk or reverse the process?” Burns asked.
That study will have to wait. Right now, Burns is working on a study that looks at the role exercise plays in Alzheimer’s.