Poorly controlled midlife diabetes could lead to increased cognitive decline, study finds

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diabetesA new study suggests that diabetes prevention and glucose control in middle age may protect against cognitive decline. The study, from Johns Hopkins Bloomberg School of Public Health, was published December 2nd in Annals of Internal Medicine.

The researchers, led by Johns Hopkins associate professor of epidemiology Dr. Elizabeth Selvin, analyzed data on over 13,000 adults aged 48 to 67 years at the beginning of the study. The health of study participants was assessed over four visits that took place between 1987 and 2013. Diabetes was defined as physician diagnosis, medication use, or HbA1c (a form of hemoglobin used to identify glucose control over prolonged periods of time) level of 6.5% or greater. The participants cognitive function was assessed on three of the visits occurring between 1990-1992, 1996-1998, and 2011-2013. Delayed word recall, digit symbol substitution, and word fluency tests were used to assess cognitive performance.

Participants who had diabetes at the beginning of the study had a 19 percent greater decline in cognitive function over 20 years than those who did not. Furthermore, the duration of diabetes correlated with the magnitude of cognitive decline over the 20 year period. Participants with prediabetes (HbA1c level of 5.7% to 6.4%.) also experienced greater cognitive decline. The researchers also added that participants with poorly controlled diabetes had greater cognitive decline than participants with controlled diabetes.

"Diabetes and glucose control are potentially modifiable and may offer an important opportunity for the prevention of cognitive decline, thus delaying progression to dementia," Dr. Selvin said.

ACSH s Dr. Gil Ross had this comment: While a 19 percent benefit over the course of decades does not rise to the miraculous level, the goal of better control of diabetes and close monitoring of HbA1C levels seems like a valid public health goal. The cognitive benefits, of whatever specific degree, are also welcome.