Diabetes may zap cognitive ability in middle age

While several studies have demonstrated poorer cognitive function in older adults with type 2 diabetes compared to older adults without diabetes, a new study in the current issue of Neurology extends this association to middle-aged adults with diabetes.

This is important for two reasons, study author Dr. Meena Kumari told Reuters Health. "Firstly, diabetes is associated with poorer cognitive performance in younger age groups, which suggests that diabetes itself is associated with cognitive decline. Secondly, as the incidence of diabetes in younger age groups is increasing, this has implications for the management of diabetes in these groups."

It is also worth noting, Kumari continued that, "we found a poorer cognitive function score in those that had been diagnosed (with diabetes) as early as two to five years previously and that it was explained by the metabolic abnormalities associated with diabetes."

For their research, Kumari and her colleague Dr. Michael Marmot, both from the International Centre for Health and Society in London, UK, examined ties between diabetes and cognitive performance in 4,020 men and 1,627 women whose average age was 56. These individuals were participants in a study that began in 1985-1988.

By 1997-1999, a total of 208 men (5 percent) and 101 women (6 percent) had developed diabetes while 405 men (10 percent) and 192 women (12 percent) had impaired glucose tolerance, a pre-diabetic condition.

Diabetes, but not impaired glucose tolerance, was associated with a significant decrement in cognitive function, Kumari and Marmot report.

For example, the odds of performing poorly on a test of inductive reasoning was 2.45 in men with diabetes and 1.83 in women with diabetes compared to those without. This relationship was not explained by confounding by age, health-related behaviors, or hypertension (high blood pressure).

SOURCE: Neurology November 22, 2005.