A recent study found that the two diseases were each tied to an increased risk of dementia. Among people with both diabetes and depression, dementia risk was even higher.
The authors of this study looked at more than 2 million older adults to determine this link between depression, diabetes and dementia.
In an editorial about this study, Charles F. Reynolds III, MD, of the University of Pittsburgh Medical Center, said he was in favor of preventing and treating depression and diabetes in an effort to help prevent dementia.
“Finally, we need lifestyle interventions, such as coaching in healthy dietary practices, in addition to [more medication options] to improve human health during aging,” Dr. Reynolds wrote.
Dimitry Davydow, MD, of the University of Washington School of Medicine in Seattle, led the current study on dementia risk factors.
These researchers studied more than 2.4 million adults ages 50 or older for about six years.
About 19 percent of the patients had been diagnosed with depression. Nine percent had type 2 diabetes. Four percent of the patients had both diseases.
Over the course of the study, 59,663 patients (2.4 percent) developed dementia. Dementia is a slowing in brain function marked by problems with memory, thinking and reasoning, as well as personality changes.
About a quarter of those patients had depression, and more than 10 percent had type 2 diabetes, Dr. Davydow and team found. Type 2 diabetes occurs when the body cannot properly process insulin. Insulin is a hormone that regulates blood sugar. Untreated type 2 diabetes can lead to health problems like heart disease and kidney damage.
Seven percent of the dementia patients in this study had both depression and diabetes.
Depression patients had an 83 percent higher risk of dementia than those who were not depressed, Dr. Davydow and team found. Diabetes appeared to increase the risk of dementia by 20 percent.
Having both illnesses increased the risk of dementia by 117 percent, Dr. Davydow and colleagues found.
“The interaction between [diabetes] and depression tended to be particularly strong for individuals younger than 65 years,” Dr. Davydow and team wrote.
In his editorial, Dr. Reynolds noted that the health challenges that come with age are interconnected. He suggested that a multifaceted approach is necessary “to meet the challenge of promoting healthy brain aging and cognitive fitness into the last years of life.”
The study and editorial were published April 15 in JAMA Psychiatry.
The Lundbeck Foundation and the National Institutes of Health funded this research. Dr. Reynolds had ties to several pharmaceutical companies, such as Pfizer and Lilly.