The findings also suggest that the risk-effect of FTO-AA on dementia is further elevated to 100 percent increased risk in the presence of APOE epsilon4, which is the highest risk variant of the APOE gene. The effect of the FTO-AA genotype on Alzheimer's and dementia risk remained after additional adjustment for diabetes, BMI, cardiovascular disease and physical inactivity.

"One of the intriguing aspects of the results is that the increased risk was independent of the traits previously associated with FTO, such as obesity and diabetes measured at baseline," Graff said. "Our results suggest that the mechanism by which FTO is associated with an increased risk for Alzheimer's and dementia may be different from how it increases the risk for obesity."

"This is a fascinating early finding, which fits with the known connections between heart health and brain health," Carrillo said. "However we do need to see these results confirmed by other researchers. In fact, we desperately need to know more, in general, about the genetics and other causes of Alzheimer's so that we have additional targets for therapies and preventions. One major positive step in that direction would be for the federal government to address its chronic underfunding of Alzheimer's disease research."

SOURCE Alzheimer's Association