Diabetes might be a significant risk factor for developing Alzheimer's disease and other forms of dementia, and could speed up the process of developing the neurological conditions by up to 40 percent. 

The first study was conducted by researchers at the Washington University in St. Louis who experimented on mice. They increased the blood sugar of the subjects into an abnormal level to determine if it will trigger changes on the beta-amyloid. Their findings showed that the production of the protein increased by 20 percent after increasing the blood sugar levels among middle-aged mice. The risk increased by 40 percent among older mice.

"Our results suggest that diabetes, or other conditions that make it hard to control blood sugar levels, can have harmful effects on brain function and exacerbate neurological conditions such as Alzheimer's disease," Shannon Macauley, study lead author and a postdoctoral research scholar, said in a press release. "The link we've discovered could lead us to future treatment targets that reduce these effects."

For the second study, researchers at the University of Pittsburgh Schools of the Health Sciences examined the brain scans, cognitive assessment results, physical exams, and medical histories of 178 participants, 97 of them were diagnosed with type 1 diabetes. The analysis showed that 33 percent of those with type 1 diabetes have severe levels of white matter damage compared to seven percent of the healthy individuals. White matter is a tissue in the brain linked to normal aging and neurological disorders.

"The clinical impact is huge over time," Dr. Caterina Rosano, senior study author and associate professor in Pitt Public Health's Department of Epidemiology, told the Wall Street Journal. "These abnormalities will impact the speed with which your brain works, and how quickly information travels from one part of your brain to another."

Both studies need further research but doctors say that the results prove that people with diabetes should be more mindful in controlling their blood sugar levels. Diabetes is becoming very common in the United States; the number of diagnosed cases has tripled between 1980 and 2011 and is affecting 20.9 million Americans.