High Blood Sugar Linked to Depression in Type 1 Diabetes

High blood sugar may be the reason behind the increased risk of depression in people with type 1 diabetes, according to a new study.

Researchers suggested that connections between departments of the brain that control emotions are altered when a neurotransmitter associated with depression (glutamate) is elevated by high-blood sugar.
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The study included 19 non-depressed adults, 3 men and 5 women with type 1 diabetes at mean age of 26, and 6 healthy men and 5 healthy women with an average age of 29 years.

MRI was used to measure brain activity in the participants while magnetic resonance spectroscopy measured the glutamate level. Participants underwent brain imaging while blood sugar levels were between 90 to 110 mg/dL and after a consistent glucose infusion (180 to 200 mg/dL).

The results showed that the diabetic patients presented reduced connections throughout regions of the brain involved with emotions once blood sugar level was increased.

Additionally, diabetic participants with bad long-term glucose control yielded a high hemoglobin level (A1c) in comparison to the good control subjects with low hemoglobin A1c.

“It was traditionally thought that patients with type 1 or type 2 diabetes have higher rates of depression than their non-diabetic peers because of the increased stress of managing a complex chronic disease,” said the study co-investigators Nicolas Bolo, PhD, from Beth Israel-Deaconess Medical Center, and Donald Simonson, MD, MPH, ScD from Brigham and Women’s Hospital.

“Our results suggest that high blood glucose levels may predispose patients with type 1 diabetes to depression through biological mechanisms in the brain,” he concluded.

The results were presented at the 2014 joint meeting of the International Society of Endocrinology and the Endocrine Society.

Reference:

Newswise. High blood sugar cases brain changes that raise depression risk [press release]. June 22, 2014. http://www.newswise.com/articles/high-blood-sugar-causes-brain-changes-that-raise-depression-risk. Accessed June 24, 2014.