Stress Responses and Memory Abnormal in Type 2 Diabetes

Many patients with type 2 diabetes have hypothalamic-pituitary-adrenal (HPA) hyperactivity and declarative memory deficits, researchers report.

Dr. Antonio Convit of New York University School of Medicine and colleagues studied 30 middle-aged diabetics and a like number of controls to compare HPA axis function and cognition. The average time since diagnosis of diabetes was 7.5 years.
Compared with the controls, the diabetic group had elevated plasma cortisol levels basally and after dexamethasone suppression, and a greater response to corticotropin-releasing hormone (CRH).
Cortisol levels during the dexamethasone/CRH test were positively associated with HbA1c. This was independent of age, body mass index and other factors.

A neuropsychological battery assessing declarative and working memory, attention, and executive function showed that cognitive impairment in the diabetics was restricted to declarative memory.

Moreover, across all subjects, declarative memory was inversely associated with cortisol levels. However, say the investigators, "these associations were subsumed by glycemic control (glycosylated hemoglobin)."

The authors call for further study of the role of the HPA axis in cognition in diabetic patients. In particular, they conclude, "improvements in glycemic control might lead to improvement in cognition."

Commenting on the findings, Dr. Convit pointed out in remarks that "most cases of type 2 diabetes are associated with weight problems and a staple of diabetes treatment is weight control."

He added, "A speculative interpretation of the data presented in the article is that given the dysregulation of the stress system, it may be a good idea to institute stress reductions strategies, such as relaxation or meditation, as part of the weight reduction plan in individuals with type 2 diabetes."
J Clin Endocrinol Metab 2007;92:2439-2445.

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FACT:

Mediterranean Diet Works For Those With Diabetes: Eating a traditional Mediterranean diet — more vegetables, fruits, and fish, and fewer animal products — does seem to ward off heart disease, an Australian study shows, and it can be especially beneficial for people with diabetes. Mediterranean-born immigrants in Australia have lower death rates from heart disease than native-born Australians, note Dr. Linton R. Harriss, from Monash University in Melbourne, and colleagues. This prompted them to investigate dietary patterns in relation to heart-related mortality "in an ethnically diverse population." “Our results suggest that the Mediterranean diet may lower mortality from ischemic heart disease."  See This Week’s Item #5