USA Today - People with diabetes are at significantly higher risk of developing all types of dementia, including Alzheimer's disease, finds a new study that bolsters previous research connecting the two illnesses. The study of more than 1,000 people in Japan found that 27 percent of those with diabetes developed dementia, compared to 20 percent of people with normal blood sugar levels. Further, the study showed that pre-diabetes -- higher than normal blood sugar levels -- also raised the risk of dementia.

USA Today article