Insulin resistance linked to larger brain grooves in adults
Estimated frontal groove-volume differences per unit of insulin resistance were 596 cubic millimeters on the left and 344 on the right.
Dose-response
Limit: Diet was unmeasured and could influence both insulin resistance and brain health
Edited by Boris Djordjevic · AgingResearch.News
An observational study examined insulin resistance and brain structure in 728 adults without diabetes: 518 men and 210 women, with a mean age of 61.4 years. Insulin resistance means cells respond less to insulin, a hormone that helps control blood sugar. Researchers measured the volume of grooves on the brain’s surface. Their analysis accounted for age, sex and the space inside the skull.
Higher insulin resistance was associated with larger grooves in the frontal part of the brain. The association appeared only in men and was strongest among participants younger than 70. The findings suggest that measuring these grooves may detect structural differences linked to metabolism in people without diabetes.
Why it matters
The findings identify insulin resistance as a potential modifiable target for preserving brain health, raising the question of whether addressing it could help maintain brain structure as people age.
Caveats
This observational study cannot establish that insulin resistance caused the brain differences or that reducing it would preserve brain health. The study did not include people with diabetes.
From the paper
- Participants
The study included 728 non-diabetic adults (518 men and 210 women) with a mean age of 61.4 ± 11.6 years (range 22–92).
- Result
Each unit increase in HOMA-IR was associated with an increase of 596.2 mm³ in left frontal sulcal volume (95% CI 372 to 821, FDR-corrected p < 0.001) and 343.5 mm³ in right frontal sulcal volume (95% CI 181 to 506, FDR-corrected p < 0.001).
Results, 3.2 Association between HOMA-IR and cerebrospinal fluid-related brain volumes
- Limitation
We cannot determine whether insulin resistance precedes sulcal enlargement or whether the two develop in parallel due to shared underlying factors.
Quoted word for word from the full text on direct.mit.edu.
- Insulin resistance
- Body mass index
- Cerebrospinal fluid-related regional volumes
- Frontal gray matter volume
- Frontal sulcal volume
- Humans
The paper
Insulin resistance and brain sulcal morphology in non-diabetic adults
Jikei University School of Medicine
Imaging Neuroscience, Oct 16, 2026, Open access
