Diabetes mellitus is associated with increased risk for developing Alzheimer’s disease. As with many areas of science, the data are inconsistent. Few studies have explored the impact of using diabetic medications and the development of Alzheimer’s disease. One study, Rotterdam study, showed that diabetics treated with insulin had a greater risk for developing Alzheimer’s disease. On the other hand, another study demonstrated that diabetics treated with insulin or oral antidiabetic drugs had a lower density of neuritic plaques (associated with Alzheimer’s disease) than individuals who do not have diabetes.

A recently published study (Journal of the American Geriatric Society, 2012, 60, 916-921) explored the association between diabetes and the use of Metformin (a popular antidiabetic drug). The data were gathered from the United Kingdom General Practice database that was established in 1987. The study was completed by assessing the data banks for individuals aged 65 and older who had a first-time diagnosis of Alzheimer’s disease between the years 1998 and 2008. The final analysis was completed on 7,086 individuals and an equal number of individuals who did not have a diagnosis of Alzheimer’s disease. The average age of cases was about 81.

On the whole, there was no increased risk of developing Alzheimer’s disease in individuals who were diabetic when compared to those who were not diabetic. Also, the risk of developing diabetes was not different for those controlling their diabetes with medications versus those who controlled their diabetes through life style.

The diabetics who used metformin to control their blood sugars had a greater risk of developing Alzheimer’s disease than those using other medications. On the other hand, those who controlled blood sugars by the use of sulfonylureas did not show increased risk of developing Alzheimer’s disease. The use thiazolidinediones (diuretics such as HCTZ) did not increase risk of developing Alzheimer’s disease.

Simply, treatment of diabetes with Metformin may increase the risk of developing Alzheimer’s disease whereas treatment with sulfonylureas, insulin (when necessary), or other diabetic drugs did not increase the risk of Alzheimer’s disease. Although not the final word, these data are encouraging as they did not show an overall association between diabetes and Alzheimer’s disease and they suggest one factor that needs to be considered when choosing the best medication for diabetes.

Unfortunately, these data do not indicate reduction of risk for Alzheimer’s disease in treated diabetics. Diabetes appears to pose a greater risk for contributing to vascular dementia (dementia due to stroke) than for developing Alzheimer’s disease. Both forms of dementia can be quit disabling and produce overlapping symptoms. Furthermore, many dementias have mixed etiology (multiple causes). Still the greatest risk factor for Alzheimer’s disease is age. Aggressive screening for management of diabetes needs to be in everyone’s life plan.