There is a growing and compelling body of evidence that Alzheimer’s and Type 2 diabetes are linked by a common factor: insulin resistance. Earlier this year, researchers at the University of Pittsburgh proved it for the first time.

If further study continues to support this finding, the implications for the growing ranks of overweight individuals at risk for type 2 are staggering. They, and their families, may well be facing the pain and expense associated with Alzheimer’s as well. According to a press release from Penn Medicine, the risk of developing Alzheimer’s disease increases by 50% for people with diabetes. Type 2 diabetes is due to insulin resistance and accounts for 90% of all diabetes cases, says the same source.

Insulin is a hormone important to many bodily functions, including the health of brain cells. The University of Pittsburgh team identified extensive abnormalities in the activity of two major signaling pathways for insulin and insulin-like growth factor in nondiabetic people with Alzheimer’s disease. These pathways could be targeted with new or existing medicines to potentially resensitize the brain to insulin and possibly slow down or even improve cognitive decline.

The study, now online in the Journal of Clinical Investigation (122 [4], 1316–38), is the first to demonstrate directly that insulin resistance occurs in the brains of people with Alzheimer’s disease.