Two recent studies shed light on dementia risk factors and its diagnosis. The first study, published in the Archives of Neurology, found that Adiponectin, a hormone derived from visceral fat, could play a role in the development of all-cause dementia and Alzheimer’s disease (AD) in women.

“Adiponectin…sensitizes the body to insulin, has anti-inflammatory properties, and plays a role in the metabolism of glucose and lipids,” the study says.

Thomas van Himbergen, PhD, from the Human Nutrition Research Center on Aging, Tufts University, Boston, and colleagues measured levels of glucose, insulin, and glycated albumin, as well as C reactive protein, lipoprotein-associated phospholipase A2, and adiponectin in the plasma of patients at the 19th biennial examination of the Framingham Heart Study.

The 840 patients (541 women, median age of 76 years) were followed up for an average of 13 years and evaluated for signs of the development of AD and all-cause dementia. During that time, 159 patients developed dementia, including 125 cases of AD.

After adjusting for other dementia risk factors, only adiponectin in women was associated with an increased risk of all-cause dementia and AD.

“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,” the authors wrote. “Our data, however, indicate that elevated adiponectin level was associated with an increased risk of dementia and AD in women.”

In a second study, researchers found that combining the use of positron emission tomography (PET) with an injected biomarker known as 18F-FDG to pinpoint key areas of metabolic decline in the brain is an effective method of detecting dementia, according to research published in the January issue of The Journal of Nuclear Medicine.

Having physiological evidence of neurodegenerative disease by imaging patients with PET could give clinicians the information they need to make more accurate diagnoses earlier than ever before, the study says.

“The new data support the role of 18F-FDG PET as an effective addition to other diagnostic methods used to assess patients with symptoms of dementia,” says Nicolaas Bohnen, MD, PhD, lead author of the study and professor of radiology and neurology at the University of Michigan, Ann Arbor, Mich.

“The review also identified new literature showing the benefit of this imaging technique for not only helping to diagnose dementia but also for improving physician confidence when diagnosing a patient with dementia. This process can be difficult for physicians, especially when evaluating younger patients or those who have subtle signs of disease.”

Physicians can use FDG-PET with high accuracy to not only help diagnose dementia but also differentiate between the individual disorders. The role molecular imaging plays in the diagnosis of dementia has expanded enough that the official criteria physicians use to diagnose patients now includes evidence from molecular imaging studies.

“For the first time, imaging biomarkers of Alzheimer’s disease are included in the newly revised clinical diagnostic criteria for the disease,” says Bohnen. “This is a major shift in disease definition, as previously an Alzheimer’s diagnosis was based mainly on a process of evaluating patients to exclude possible trauma, hemorrhage, tumor, or metabolic disorder. Now it is becoming a process of inclusion based on biomarker evidence from molecular imaging.”

This review presents the most up-to-date and salient evidence of FDG-PET’s usefulness for the evaluation of patients with suspected dementia.

The objective of the study was to replace prior retrospective reviews that were performed as the technique was just emerging and that suggested methodological improvements. The new review includes studies with better methodology, including confirmation of diagnoses with autopsy, more expansive recruitment of subjects, and use of multi-center studies.

After reviewing 11 studies that occurred since the year 2000 and that met more stringent study review standards, researchers conclude that 18F-FDG is highly effective for detecting the presence and type of dementia.