A recent study suggests that severe hypoglycemic episodes are associated with a greater risk of dementia.

It has long been understood that people who have diabetes also have an increased risk of dementia. For example, a study in 2004 found that diabetes mellitus was linked to a 65 percent increased risk of developing Alzheimer's disease. In that study, 824 people were followed for over 5 years; 151 of the participants developed Alzheimer's dementia, including 31 who had diabetes.

But that study didn't look at an intriguing issue: whether there's a relationship of hypoglycemia with subsequent development of dementia. A more recent study sheds some light on this issue. In this study, researchers studied hospital discharge and emergency department diagnoses of 16,667 older patients with type 2 diabetes. Hypoglycemic events from 1980-2002 were reviewed. Since they were looking at hospital and ER records, one can assume that these were all severe episodes (severe episodes of hypoglycemia are usually defined as those requiring assistance from someone else to be treated). The authors found that, compared with patients with no hypoglycemia, patients with single or multiple episodes had a graded increase in risk: the more episodes of hypoglycemia, the higher the risk: "In older patients with a history of one episode, they had a 26 percent greater risk of dementia. Patients with two episodes had a 115 percent greater risk of dementia. And patients with three or more episodes had a 160 percent greater risk of dementia," the lead author was quoted as saying.

Consider Hypoglycemia Severity

The authors concluded that a history of severe hypoglycemic episodes was associated with a greater risk of dementia. But whether minor hypoglycemic episodes might also increase the risk of dementia was not evaluated in this study. And whether the presumed relationship of occasional severe hypoglycemia and subsequent dementia is sufficient to explain the relationship of diabetes to dementia, as there are alternate explanations possible for why people with diabetes might develop dementia. The most worrisome would simply be that people with occasional episodes of severe hypoglycemia might also have multiple undocumented episodes of mild hypoglycemia. If this were true, then anybody with diabetes and frequent mild hypoglycemia might be at increased risk of developing dementia.

Also, the study did not evaluate younger people with diabetes; the average age of the patients in this study was 65 years. A much larger study, both in size and duration, would be needed to evaluate whether these results would have been found in younger people.

Review Guidelines for Hypoglycemia Prevention and Treatment

What do these studies indicate for people with diabetes who are struggling to get their blood glucose down, and occasionally overdo it? Well, for starters, be prepared for lows. They can occur to anyone on insulin, but also to folks on many oral diabetes medications. The standard guidelines for prevention and treatment of hypoglycemia should be understood. A comprehensive discussion is at this website, and if you are not yet aware of such guidelines, please be sure to review them: click here.

And if you are having hypoglycemic episodes that are severe enough to require assistance from another person, whether by them feeding you sugar-containing foods, or giving you a glucagon injection, or taking you to an emergency room, then a thorough reevaluation of your diabetes program would be in order.

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Also see:
Diabetes Linked to Increased Risk of Alzheimer's in Long-Term Study
NIH News, May 19, 2004 at the Diabetes Monitor: http://www.diabetesmonitor.com/pr38.htm

Diabetes Mellitus and Risk of Alzheimer Disease and Decline in Cognitive Function.
Arch Neurol. 2004;61(5):661-666.
http://archneur.ama-assn.org/cgi/reprint/61/5/661

Low Blood Sugar a Dementia Risk for Diabetics
ADA, "In Diabetes Today," April 14, 2009
http://www.diabetes.org/diabetesnewsarticle.jsp?storyId=19904386&filename=20090414/reuters20090414health00000011reutershealthewEDIT.xml

Hypoglycemic Episodes and Risk of Dementia in Older Patients With Type 2 Diabetes Mellitus
JAMA, April 15, 2009; 301: 1565 - 1572.
http://jama.ama-assn.org/cgi/content/abstract/301/15/1565