Diabetes mellitus (DM) appears to be associated with an increased risk for Alzheimer’s Disease and other dementias. One possible pathway for this risk is through episodes of hypoglycemia, which may cause brain damage and harm the brain’s ability to use energy. It is difficult to assess the influence of hypoglycemia on the development of dementia, however, because individuals with dementia may be less able to successfully manage their DM treatments and to respond appropriately to the initial symptoms of hypoglycemia. Therefore, it is important to evaluate the long-term associations between dementia and hypoglycemia.
A recent study in JAMA Internal Medicine reported on a longitudinal, population-based study of 783 older adults with DM, which suggested that there is a bidirectional relationship between hypoglycemia and dementia. The researchers studied participants in a prospective cohort study (the Health, Aging and Body Composition Study) which, over a period of 12 years, followed the long-term health of black and white older adults living in Memphis and Pittsburgh, who were between 70 and 79 years of age at their entry to the study. Participants were, at baseline, able to independently perform activities of daily living, free of a diagnosis of dementia, and able to engage in moderate physical activity. The researchers were able to track DM diagnosis, insulin use, episodes of severe hypoglycemia (based on hospital data), cognitive ability and dementia onset, and a variety of demographic and health data throughout participants’ involvement in the study. The health and demographic data allowed the researchers to control for the effects of these related variables, and the cognitive and DM-related data allowed the researchers to examine the relationship between DM and dementia onset, all among a somewhat diverse population of older adults.
Over the 12 years for which data were collected, 7.8 percent of participants had a hypoglycemic event, and 18.9 percent developed dementia. Each of these was a risk factor for the other, as individuals who were initially without dementia were about twice as likely to develop dementia after a hypoglycemic event, while individuals who developed dementia were more likely to experience a hypoglycemic event after dementia onset. This study suggests that cognitive function is an important clinical consideration for individuals with DM, and that caregivers for individuals with dementia should be educated on the symptoms and treatment of hypoglycemia.
Yaffe K, Falvey CM, Hamilton N, et al. Association between hypoglycemia and dementia in a biracial cohort of older adults with diabetes mellitus. JAMA Internal Medicine. (2013). DOI: 10.1001/jamainternalmed.2013.6176