Could Insulin Resistance Increase Women’s Risk of Cognitive Decline?

Insulin resistance could be linked to worse verbal cognitive function in women, according to a recent study.

“Insulin resistance occurring during mid-life may increase the risk of cognitive decline later in life. We hypothesized that insulin resistance is associated with poorer cognitive performance and that sex and apolipoprotein E Ɛ4 allele (APOE*E4) might modulate this association,” explained the study’s authors.
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For the nationwide, Finnish population-based study, researchers evaluated insulin resistance in 5935 participants (mean age 52.5 years) using Homeostasis Model Assessment-Insulin Resistance (HOMA-IR).

To test cognitive function, researchers used word-list learning, simple and visual-choice reaction-time tests, and word-list delayed-recall, and used linear regression analysis to compare results between HOMA-IR and cognitive testing.

The study showed that HOMA-IR results were linked to poorer verbal fluency in women, but not in men (P<0.0001 vs. P=0.56).

Further, while higher HOMA-IR scores yielded poorer verbal fluency in individuals that were APOE*E4 negative (P=0/0003), they were not associated to poorer verbal function in APOE*E4 carriers (P=0.28).

“To our knowledge, this is the first comprehensive, population-based study, including both young and middle-aged adults, to report that female sex impacts the association of HOMA-IR with verbal fluency. Our study was cross-sectional, so causal effects of HOMA-IR on cognition could not be evaluated,” they concluded.

The complete study published in the August issue of Diabetologia.

-Michelle Canales Butcher

Reference:

Ekblad LL, Rinne JO, Puukka PJ, et al. Insulin resistance is associated with poorer verbal fluency performance in women. Diabetologia. 2015 August [epub ahead of print] doi:10.1007/s00125-015-3715-4.