People who develop diabetes prior to turning 65 years old may have an increased risk of Alzheimer's disease.
Dr Margart Gatz, who contributed to the study, found the increased risk was particularly strong in people who found they were diabetics during middle age, which corresponded to a 125 percent increased risk for dementia.
The finding comes from an ongoing study of 13,693 Swedish twins aged 65 or older that began in 1998.
The results point to adult choices such as exercise, diet and smoking in affecting the risk for Alzheimer's disease and diabetes.
"Our results highlighted the need to maintain a healthy lifestyle during adulthood in order to reduce the risk of dementia late in life," Gatz said.
The number of senior citizens suffering from diabetes and Alzheimer's disease is expected to increase in the coming years due to more baby boomers reaching retirement age.
Approximately 21 million people in the U.S. have diabetes, according to the American Diabetes Association. There are about 30 percent of older adults with diabetes who have not been diagnosed.