Having diabetes or prediabetes in midlife is associated with a greater risk for cognitive decline later in life, according to a study published in Annals of Internal Medicine.

Approximately 10 percent of the U.S. population has type 2 diabetes, putting them at risk for several adverse health outcomes, including dementia. Cognitive decline is a precursor to dementia. Hemoglobin A1c (HbA1c) level is a measure of the average circulating glucose level in the blood over the preceding 2 to 3 months and studies have shown an association between HBA1c level and cognitive scores in those with diabetes.

Researchers studied 13,351 adults aged 48 to 67 years to determine whether diabetes in midlife is associated with 20-year cognitive decline and to characterize long-term cognitive decline across clinical categories of HbA1c. Diabetes status and cognitive function were established at baseline and cognitive function was assessed periodically during the 20-year follow-up. The researchers found significantly greater cognitive decline among adults with diabetes and prediabetes than those without diabetes at baseline, and those with longer-duration diabetes were found to have greater cognitive decline.

Article: Diabetes in Midlife and Cognitive Change Over 20 Years: A Cohort Study, A.M. Rawlings, A.R. Sharrett, A.L.C. Schneider, J. Coresh, M. Albert, D. Couper, M. Griswold, R.F. Gottesman, L.E. Wagenknecht, B.G. Windham, and E. Selvin, Annals of Internal Medicine, doi: 10.7326/M14-0737, published 1 December 2014.