The Study

According to a April 2008 Swedish Study, men who develop diabetes in middle age may be at greater risk of Alzheimer's disease.

The study included nearly 2,300 Swedish men who had glucose testing at age 50 to check for diabetes, a metabolic disease caused by abnormal insulin levels. The men were then followed for 32 years.

Results

The results: 102 were diagnosed with Alzheimer's disease, 57 with vascular dementia, and 235 with other types of dementia or cognitive impairment, the researchers said. The study also found that the men with low insulin levels at age 50 were nearly one-and-a-half times more likely to develop Alzheimer's disease than men who didn't have insulin problems. The risk of Alzheimer's increased, regardless of blood pressure, cholesterol, Body Mass Index (BMI) and education.

Conclusions

The results suggest a link between insulin problems and the origins of Alzheimer's disease and emphasize the importance of insulin in normal brain function.

According to the researchers, "It's possible that insulin problems damage blood vessels in the brain, which leads to memory problems and Alzheimer's disease, but more research is needed to identify the exact mechanisms."

The findings were published in the April 9 online issue of Neurology.

Other Studies

Another study, published in the April 8 print issue of Neurology, found that depression appears to more than double the risk of developing Alzheimer's. Depression has been linked to an increased risk of Alzheimer's, and many researchers have suspected that risk is tied to changes in the brain caused by depression. The theory has been that depression shrinks specific areas, leaving the brain vulnerable to the development of Alzheimer's.

Other researchers have proposed that depression leads to a loss of cells in the areas of the brain called the hippocampus and the amygdala, thereby increasing the risk for Alzheimer's disease.

More Studies Needed

More studies are needed to understand the relationship between depression and dementia since it is not yet knownwhether depression contributes to the development of Alzheimer's disease or whether another unknown factor causes both depression and dementia.

SOURCES: April 9, 2008, news release, American Academy of Neurology