A fat hormone is linked to Alzheimer’s disease

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Leptin, a hormone that is central to controlling metabolism and weight, also appears important in the development of dementia and Alzheimer’s disease, according to a growing body of research. In a study published today, researchers found people with higher levels of leptin had higher total cerebral brain volume and a lower incidence of dementia and Alzheimer’s disease.

Leptin is produced by fat cells. Normal levels promote a feeling of fullness and prevent overeating. People who are obese, however, develop resistance to the effects of leptin.

Previous studies, much of it in animals, has suggested that leptin also reduces the production of amyloid plaques found in the brains of people with Alzheimer’s disease and protects the brain in other ways. Moreover, studies in humans have shown that being overweight and obese in middle-age increases the risk of developing dementia later in life.

In the study, published in the Journal of the American Medical Assn., Boston University researchers measured leptin levels in 785 people (with an average age of 79) without dementia. A subset of 198 of those people had brain MRI scans approximately 7.7 years after leptin levels were measured. After 12 years of follow-up, the researchers concluded that people with the highest levels of leptin had a 6% risk of developing Alzheimer’s disease compared with a 25% risk for people with the lowest leptin levels. Higher leptin levels were also associated with higher total cerebral brain volume.

‘If our findings are confirmed by others, leptin levels in older adults may serve as one of several possible biomarkers for healthy brain aging and, more importantly, may open new pathways for possible preventive and therapeutic intervention,’ the authors wrote in the paper.

— Shari Roan