TUESDAY, Jan. 3, 2012 (HealthDay News) -- Rising levels of a hormone associated with sensitizing the body to insulin appears to raise the risk for developing dementia and Alzheimer's among women, new research reveals.
The hormone in question, adiponectin, is derived from visceral fat. It is known to play a role in regulating the metabolism of glucose and lipids, while also carrying certain anti-inflammatory characteristics.
So, the finding is therefore somewhat unexpected, given that insulin resistance and inflammation are considered to be hallmarks of both type 2 diabetes and Alzheimer's disease (AD). The logical presumption would have been that anything that lowers insulin resistance and inflammation might also reduce the risk for dementia.
Study leader Thomas van Himbergen, of the Lipid Metabolism Laboratory with the Human Nutrition Research Center on Aging at Tufts University in Boston, and his colleagues report their finding online Jan. 2 in the Archives of Neurology.
"It is well established that insulin signaling is dysfunctional in the brains of patients with AD, and since adiponectin enhances insulin sensitivity, one would also expect beneficial actions protecting against cognitive decline," van Himbergen said in a journal news release. "Our data, however, indicate that elevated adiponectin level was associated with an increased risk of dementia and AD in women."
The authors note that the global incidence of dementia is projected to double over the next two decades, at which point it will affect roughly 72 million people.
To get at possible mechanism and indicators of the onset of Alzheimer's, the team took blood samples from 541 women over the course of 13 years. The samples were measured for levels of a number of markers, including glucose, insulin and adiponectin. All patients were simultaneously monitored for dementia symptoms.
During the study, 159 patients went on to develop dementia, of which 125 were Alzheimer's cases.
In the end, the investigators concluded that only a rise in adiponectin signaled an increased risk for both all-cause dementia and/or Alzheimer's.
For more on dementia, visit the Alzheimer's Association.