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Diabetes may worsen cognitive function in middle age

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December 18, 2018

Middle-aged adults with diabetes performed worse on assessments of executive function, attention and memory when compared with adults without diabetes, independent of other cardiovascular risk factors and depression status, according to findings from a population-based study.

“Recently, attention has been given to modifiable risk factors to help curtail the increasing prevalence of dementia, and several trials have shown mixed results,” Leonardo Tamariz, MD, MPH, a clinician investigator in the division of general internal medicine at the University of Miami, and colleagues wrote in the study background. “At the same time, improvement in the control of diabetes decreases the cognitive impact on patients with diabetes. However, most of these data are derived from elderly adults. There is very limited information regarding the onset of cognitive changes and the prevalence of cognitive decline among middle-aged adults with diabetes.”

In a cross-sectional study, Tamariz and colleagues analyzed data from 309 adults aged 55 to 65 years with (n = 142; mean diabetes duration, 10.15 years) and without diabetes (n = 167) recruited from Guayaquil, Ecuador. Participants completed standardized neuropsychological tests including nine verbal and nonverbal tasks assessing three cognitive domains. Researchers also collected data on depression, education level, smoking status and alcohol use, and used analysis of variance to assess differences between participants with and without diabetes.

Compared with participants without diabetes, those with diabetes were more likely to be women (54.2% vs. 30.5%), attained less education (mean, 11.82 years vs. 13.32 years; P < .05) and had a greater mean waist circumference (98.31 cm vs. 93.57 cm; P < .01); however, control participants had higher total cholesterol, LDL cholesterol and HDL cholesterol vs. those with diabetes (P < .01 for all three).

Researchers found that people with diabetes performed significantly worse on all assessed measures of memory, attention, information processing and executive function when compared with controls.

“On memory tasks, patients with diabetes learned and recalled fewer number of words and fewer details of a complex figure on both immediate and delayed recall conditions,” the researchers wrote. “On tests of attention and information processing speed, they repeated fewer digits, read fewer words and named fewer colors than the control group.”

Additionally, participants with diabetes took more time vs. controls to complete simple, numerical sequences and make yes-or-no choices on the choice reaction time task, they wrote. On part B of the Trail Making Test, participants with diabetes both took longer to complete the task and committed more errors vs. controls (P = .002), according to researchers.

In multivariate analysis, diabetes status was a predictor of performance on most memory tasks, with results persisting after adjustment for education level, hypertension and depressive symptoms.

The researchers noted that they did not observe dementia or mild cognitive impairment in the cohort, but rather abnormal neuropsychological tests.

“The main implication of our study is that mild cognitive impairment is prevalent among middle-aged adults with diabetes; therefore, the scientific community needs to implement screening strategies to identify patients with cognitive impairment,” the researchers wrote. – by Regina Schaffer

Disclosures: The authors report no relevant financial disclosures.

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