There is a growing body of evidence that DM may increase the risk for developing cognitive impairment, including Alzheimer disease and vascular dementia, and there is research interest in whether DM treatment can prevent cognitive decline. When blood glucose declines to low levels, cognitive function is impaired and severe hypoglycemia may cause neuronal damage. Previous research on the potential association between hypoglycemia and cognitive impairment has produced conflicting results, the authors write in the study background.
Kristine Yaffe, M.D., of the University of California, San Francisco, and colleagues studied 783 older adults with DM (average age 74 years). During a 12-year follow-up, 61 patients (7.8 percent) had a reported hypoglycemic event and 148 (18.9 percent) developed dementia.
"Hypoglycemia commonly occurs in patients with diabetes mellitus (DM) and may negatively influence cognitive performance. Cognitive impairment in turn can compromise DM management and lead to hypoglycemia," according to the study.
Patients who experienced a hypoglycemic event had a two-fold increased risk for developing dementia compared with those who did not have a hypoglycemic event (34.4 percent vs. 17.6 percent). Older adults with DM who developed dementia had a greater risk for having a subsequent hypoglycemic event compared with patients who did not develop dementia (14.2 percent vs. 6.3 percent), according to the study results.
"Among older adults with DM who were without evidence of cognitive impairment at study baseline, we found that clinically significant hypoglycemia was associated with a two-fold increased risk for developing dementia ... Similarly, participants with dementia were more likely to experience a severe hypoglycemic event," the authors conclude. "The association remained even after adjustment for age, sex, educational level, race/ethnicity, comorbidities and other covariates. These results provide evidence for a reciprocal association between hypoglycemia and dementia among older adults with DM."