Dr. Margaret Gatz, a professor of psychology, gerontology and preventative medicine at the University of Southern California, conducts research on interventions that may reduce the risk of Alzheimer’s disease. In a recent study, published in the January 2009 issue of the journal Diabetes, Dr. Gatz and her team tracked rates of dementia and diabetes in Swedish twins and discovered that developing type 2 diabetes before the age of 65 was associated with a 125 percent increased risk of subsequently developing Alzheimer’s disease.

1. How did you become interested in the relationship between diabetes and dementia?

Our research began with the question why some people develop dementia, especially Alzheimer’s disease, in old age, whereas others do not. Alzheimer’s disease is the most common type of dementia, followed by vascular dementia, which is generally caused by the same things that are risk factors for stroke.

Recently, a number of researchers have begun to show that vascular risk factors are important not only for increasing risk of vascular dementia but also for increasing risk of Alzheimer’s disease. This observation is particularly interesting because vascular risk factors are potentially modifiable. In other words, people might be able to reduce their risk of Alzheimer’s disease by attending to the kinds of health behaviors that reduce vascular risk, such as controlling blood pressure, cholesterol and diabetes. What led our research group to be interested in diabetes was the search for potential ways to lower risk of Alzheimer’s disease.

We were fortunate to be able to launch the Study of Dementia in Swedish Twins, building on the Swedish Twin Registry, to identify a population of twins where one or both members of the pair have developed dementia. Because the participants are twins, they are genetically similar, and that permits us to ask specifically what is different in the lives of those twins when one has dementia and the other does not.