A recent study by Japanese researchers reveals that diabetics are more than twice as likely to develop Alzheimer’s disease, and they are at increased risk of developing some form of dementia, reported the Los Angeles Times.
While more than 8 percent of American adults have diabetes, according to the National Institutes of Health, more than 16 percent of American Indians and Alaska Natives (aged 20 years and older who are served by the Indian Health Service) have been diagnosed with the metabolic disorder that causes a life-threatening buildup of blood sugar or glucose. Diabetes rates vary by region, and American Indians in southern Arizona suffer the highest rates of the disease at 33.5 percent.
While other researchers have found an association between diabetes and dementia, the link was never widely confirmed. So researchers from Kyushu University in Japan analyzed "1,017 community-dwelling dementia-free subjects" over the course of 15 years. The result, Alzheimer disease and vascular dementia (caused by impaired blood flow to the brain) "were significantly higher in subjects with diabetes than in those with normal glucose tolerance."
Even after taking other risk factors into account, such as age, body mass index and lifestyle factors, those who had been diagnosed with diabetes had a 74 percent increased risk of being diagnosed with some type of dementia over the course of the 15-year study, which was published in the September 20 edition of the journal Neurology. Non-diabetics with "impaired glucose tolerance"—potentially prediabetic—were 35 percent more likely to develop dementia, the researchers found.
While it is still unclear why diabetes increases susceptibility to dementia, researchers suggested four possible explanations: artherosclerosis (hardening of the arteries) and microvascular disease would limit blood flow to the brain, and glucose intolerance could also increase oxidative stress and metabolism problems in the brain, researchers stated.