Type 1 Diabetes Increases Dementia Risk

WASHINGTON, DC—Patients in late life with type 1 diabetes have an approximately 93% increased risk of dementia, compared with patients who do not have diabetes, according to data from a 12-year observational study described at the 2015 Alzheimer’s Association International Conference. The risk appears similar to that for those with type 2 diabetes, said Rachel Whitmer, PhD, Senior Scientist at the Kaiser Permanente Division of Research in Oakland, California.

Rachel Whitmer, PhD

Prior studies had examined dementia risk for patients with type 2 diabetes, but researchers had not examined risk for patients with type 1 diabetes. Patients with type 1 diabetes are living longer, and understanding how cognition changes in those patients is important. “Even a small problem with your cognitive function could interfere with your ability to self-care,” Dr. Whitmer said. Older people with type 1 diabetes are different from those with type 2 diabetes in that they have a younger age of diabetes onset, continuous insulin treatment, more frequent severe hypoglycemic episodes, and fewer vascular risk factors, she said.

To evaluate dementia risk in older people with type 1 diabetes, Dr. Whitmer and her research colleagues followed the health histories of 490,344 people in the Kaiser Permanente health system. The patients were older than 60 with no prior dementia. The investigators identified 334 patients with type 1 diabetes in that group, and 53 of those patients (16%) received diagnoses of dementia over 12 years.

The researchers evaluated risk using a Cox proportional hazard model. Controlling for vascular risk factors (ie, stroke, peripheral arterial disease, and hypertension) those with type 1 diabetes had a 73% increased risk, compared with those who did not have diabetes. When researchers included patients with type 2 diabetes in the overall comparison group, those with type 1 diabetes were approximately 83% more likely to receive a diagnosis of dementia, or 61% more likely after researchers considered vascular risk factors.

Investigators plan to follow a cohort of patients with type 1 diabetes to examine cognitive function over five years, said Dr. Whitmer. “People with type 1 diabetes are living longer than ever before,” she said. “More research is needed to identify risk and protective factors for Alzheimer’s and other dementias in this group that is newly entering the aging population.”

—Jake Remaly