Higher intraindividual fasting glucose (FG) variability during young adulthood below the threshold of diabetes was associated with worse processing speed, memory, and language fluency in middle adulthood, a new study found. Researchers studied 3,307 CARDIA (Coronary Artery Risk Development Study in Young Adults) participants (aged 18‒30 years; 1985-1986) at baseline and calculated 2 measures of long-term glucose variability: the coefficient of variation about the mean FG (CV-FG) and the absolute difference between successive FG measurements [average real variability (ARV-FG)] before the onset of diabetes over 25 and 30 years of follow-up. Cognitive function was assessed at 25 and 30 years. Among the findings:

• After multivariable adjustment, 1-SD increment of CV-FG was associated with worse cognitive scores at year 25.
• Findings were similar between CV-FG with each cognitive test score at year 30 and when an alternative measure of variability (ARV-FG) was used that captured variability in successive FG values.