Falling Glucose, Foggy Thinking

Hypoglycemia may raise dementia risk in aging diabetes patients

/ Author:  / Reviewed by: Joseph V. Madia, MD

(RxWiki News) Balanced blood sugar keeps energy circulating through the brain. Several studies have explored the effect of blood sugar levels on that major organ, which controls every other organ and aspect of the human body.

A new study has concluded that low blood sugar levels can greatly impair diabetes patients' thinking skills.

This study also showed that impaired thinking can hinder diabetes management, sometimes driving blood sugars dangerously down.

Hypoglycemia — that dip in levels of blood sugar, or glucose — may double the risk that older adults will develop dementia, the researchers concluded.

"Control your blood sugar to help prevent diabetes."

The study's lead author was Kristine Yaffe, MD, of the psychiatry department at the University of California San Francisco.

Dr. Yaffe and her research team selected 783 diabetes patients from the Health, Aging, and Body Composition (Health ABC) study. The study ran for 12 years, beginning in 1997.

Of the 783 people studied, 47 percent were black and 53 percent were white. Females accounted for 47.6 percent of the group, while men comprised the remainder. The average age within the group was 74.

The researchers tracked hospital admissions in which dementia was diagnosed and periods when dementia medication was prescribed. 

Sixty-one patients, or 7.8 percent of study participants, experienced a hypoglycemic event during those dozen years. Dementia developed in 148 people, or 18.9 percent of the study pool.

Almost 35 percent of those who experienced a hypoglycemic event developed dementia, and almost 18 percent of those who did not experience a hypoglycemic event developed dementia.

Also, the diabetes patients who developed dementia were at three times greater risk for having a hypoglycemic event after that cognitive impairment was reported: 14.2 percent of dementia patients had future hypoglycemic events, while 6.3 percent of those without dementia had subsequent hypoglycemic events.

"Recurrent severe hypoglycemia has been shown to result in brain damage," the researchers wrote. "Our findings emphasize the importance of cognitive function in the clinical management of older adults with [diabetes]."

"Certain medications known to carry a higher risk for hypoglycemia, such as insulin secretagogues and some sulfonylureas, may be inappropriate for older patients with or at risk for cognitive impairment."

Physicians and other health professionals, as well as non-medical caregivers of people with diabetes, should be aware of the higher risk for hypoglycemia in patients with dementia, the researchers added. That, in part, is because symptoms of hypoglycemia in older adults sometimes are misinterpreted, which can delay treatment.

This study included those who had diabetes from the start of the investigation and those who developed diabetes during the study’s follow-up period.

Alzheimer’s disease is the most common type of dementia. Vascular dementia, which occurs after a stroke, is the second-most common. The researchers cited what they described as growing evidence of the link between those two forms of extreme cognitive impairments and diabetes. Not all studies in that area have concluded there was an association, they added.

Now, the researchers wrote, there needs to be more scientific evidence of possible long-term effects of hypoglycemia on older adults with diabetes. The brain itself, they wrote, is more vulnerable as people age.

The study was published June 10 in the Journal of the American Medical Association.

Dr. Yaffe has been a consultant to or sat on data monitoring boards for several pharmaceutical companies.

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Review Date: 
June 9, 2013
Last Updated:
August 7, 2013