Relationship between body mass index, gray matter volume and peripheral inflammation in patients with post-COVID...

Obesity, a condition associated with low-grade peripheral inflammation, is an independent risk factor for severe COVID-19 and has been linked to structural brain alterations. Given that post-COVID condition (PCC) is also associated with structural brain abnormalities and lingering immunological alterations, this study aimed to assess whether obesity contributes to these neural and immunological differences in PCC patients.

We investigated a previously established cohort of PCC patients (n = 61), recruited between April 2021 and June 2022. Whole-brain comparison of gray matter volume (GMV) was conducted by voxel-based morphometry (VBM). Obesity, as measured by body mass index (BMI), as well as age, sex, and total intracranial volume (TIV), were included as regressors in a linear model. Signature immunological markers were quantified in 50 participants using a LEGENDplex™ multiplex bead-based assay.

A significant negative association was found between BMI and GMV in the right thalamus (p(FWE) = 0.039, k = 209, TFCE = 1037.97, x = 18, y = -21, z = 8). Moreover, BMI and thalamic GMV were significantly associated with immunological markers in PCC. Specifically, BMI was positively associated with Interleukin-6 (p = 0.021) and negatively with Interleukin-7 (p = 0.021), while GMV showed positive associations with Interleukin-8 (p = 0.05).

The results suggest that BMI contributes to GMV alterations in PCC patients, with both BMI and GMV demonstrating correlations with peripheral immunological markers. These findings indicate that converging mechanisms involving inflammation and structural brain alterations may contribute to obesity and PCC.