Higher Insulin levels may be related to impaired cognition in women
There is evidence to suggest that type2 diabetes mellitus and increased insulin levels may be associated with impaired cognition. How much of this impaired cognition is caused by diabetes and insulin levels is currently unknown. A new study published in the Archives of Internal Medicine is aimed at solving this question.
The study was conducted by Olivia Okereke MD and colleagues from various institutions including Channing Laboratory and Harvard Medical School. The study focused on non-diabetic patients to resolve the issue impaired cognition.
The researchers measured the C peptide level, representing insulin secretion, in blood samples. A total of 718 women participated in the study and the study was conducted during a period from June 14, 1989, to October 4, 1990. The range of age of these women who participated in the study ranged from 61 to 69 years.
The study was conducted through telephone interviews after an average of 10 years after blood collection, testing general cognition, verbal memory, category fluency, and attention. Olivia Okereke MD and colleagues conducted a second cognitive assessment 2 years after the initial interview. The primary outcomes were global cognitive function across all tests and verbal memory. The researchers used regression models to estimate multivariable-adjusted mean differences in cognitive function and cognitive decline, and odds of cognitive impairment, across C peptide levels.
The researchers found that cognitive function was worse among women in the fourth C peptide quartile compared with those in the first quartile (eg, on the global score combining all cognitive tests, the multivariable-adjusted mean difference was -1.7 standard units, the odds of cognitive impairment (defined as the worst 10% of the distribution) were 3-fold higher among women in the fourth vs first. On verbal memory, women in the fourth quartile scored significantly worse than those in the first quartile; the odds of impairment were 2.8-fold higher. Consistent findings were observed for cognitive decline.
From these findings the researches have concluded that higher insulin secretion may be related to worse cognition, even among those who have no diabetes.
Ref: Arch Intern Med. 2005;165:1651-1656.