Adult-onset diabetes slows mental functioning in several ways, with deficits appearing early

Jan 05, 2009

Adults with diabetes experience a slowdown in several types of mental processing, which appears early in the disease and persists into old age, according to new research. Given the sharp rise in new cases of diabetes, this finding means that more adults may soon be living with mild but lasting deficits in their thought processes.

A full analysis appears in the January issue of Neuropsychology, which is published by the American Psychological Association.

Researchers at Canada's University of Alberta analyzed a cross-section of adults with and without adult-onset Type 2 diabetes, all followed in the Victoria Longitudinal Study. At three-year intervals, this study tracks three independent samples of initially healthy older adults to assess biomedical, health, cognitive and neurocognitive aspects of aging. The Neuropsychology study involved 41 adults with diabetes and 424 adults in good health, between ages 53 and 90.

The research confirmed previous reports that diabetes impairs cognition and added two important findings. First, it teased out the specific domains hurt by diabetes. Second, it revealed that the performance gap was not worse in the older group. Thus, the reductions in executive function and processing speed seem to begin earlier in the disease.

Healthy adults performed significantly better than adults with diabetes on two of the five domains tested: executive functioning, with significant differences across four different tests, and speed, with significant differences or trends across five different tests. There were no significant differences on tests of episodic and semantic memory, verbal fluency, reaction time and perceptual speed.

When researchers divided participants into young-old and old-old, with age 70 as the cutoff, they found the same pattern of cognitive differences between young-old and old-old in the diabetes and control groups. Thus, the researchers concluded, the diabetes-linked cognitive deficits appear early and remain stable.

"Speed and executive functioning are thought to be among the major components of cognitive health," says co-author Roger Dixon, PhD. With Type 2 diabetes a growing concern among adults of all ages, but especially those above age 30, Dixon says that public health programs could check the cognitive status of people with more advanced or severe cases; ensure that diet and medications are effectively employed in all early diagnosed cases; and enact possible cognitive monitoring or training programs for people with diabetes. According to the U.S. Centers for Disease Control and Prevention, new cases of diabetes nearly doubled in the past decade, with nearly one new case for every 100 adults between the years 2005 and 2007.

The normal age-related slowing of thought processes could be exacerbated by diseases such as Type 2 diabetes, says Dixon. But, he continues, "There could be some ways to compensate for these declines, at least early and with proper management." The level of impairment detected, he adds, should not make it hard for people to manage their condition.

Diabetes is a known risk factor for late-life neurodegenerative diseases such as Alzheimer's. Although the deficits detected in the current sample were not clinically significant, they appear (according to subsequent research by the authors) to foreshadow additional deficits. Only further study would reveal whether it's possible to "connect the dots" between mild early deficits in speed and executive function, and later signs of a progressive cognitive impairment.

Article: "Exploring Effects of Type 2 Diabetes on Cognitive Functioning in Older Adults," Sophie E. Yeung, PhD, Ashley L. Fischer, PhD, and Roger A. Dixon, PhD, University of Alberta; Neuropsychology, Vol. 23, No. 1.

Source: American Psychological Association

Explore further: Treatment of substance abuse can lessen risk of future violence in mentally ill, study finds

add to favorites email to friend print save as pdf

Related Stories

Recommended for you

Lift weights, improve your memory

1 hour ago

Here's another reason why it's a good idea to hit the gym: it can improve memory. A new Georgia Institute of Technology study shows that an intense workout of as little as 20 minutes can enhance episodic ...

Fat chats: The good, the bad and the ugly comments

3 hours ago

Cyberbullying and hurtful 'fat jokes' are disturbingly prevalent in the social media environment, especially on Twitter, says Wen-ying Sylvia Chou of the National Institutes of Health in the US. Chou is lead ...

Omega-3 fatty acids may prevent some forms of depression

5 hours ago

Patients with increased inflammation, including those receiving cytokines for medical treatment, have a greatly increased risk of depression. For example, a 6-month treatment course of interferon-alpha therapy ...

Ethical behavior can be contagious, study says

6 hours ago

A new study from Penn State Smeal College of Business faculty members Steven Huddart and Hong Qu examines the power of social influence on managers' ethical behavior. The Department of Accounting researchers find that managers ...

User comments : 0