Impact of elevated body mass index (BMI) on cognitive functioning and inflammation in persons with post-COVID-19 condition: a secondary analysis

Background: Individuals who have recovered from the acute stage of SARS-CoV-2 infection may be at risk of developing post-COVID-19 condition (PCC), characterised by a spectrum of persisting, non-specific, and functionally impairing symptoms across multiple organ systems. Obesity has been implicated as a risk factor for PCC, mediated by chronic systemic inflammation. The foregoing has also been separately reported to mediate cognitive dysfunction in PCC. Methods: This is a post-hoc analysis of a randomised, double-blinded, placebo-controlled clinical trial evaluating vortioxetine treatment for cognitive impairments in persons with PCC who received vortioxetine or placebo for eight weeks. This analysis comprises baseline data, examining the impact of BMI on cognitive functioning measured by the Digit Symbol Substitution Test (DSST) and Trails Making Tests (TMT)-A/B, as well as inflammation, via serum c-reactive protein (CRP) and erythrocyte sedimentation rate (ESR). Results: Complete data from 70 participants were statistically analysed and adjusted for age and sex. BMI was negatively correlated with performance on the DSST (beta = -0.003, p = 0.047), TMT-A (beta = -0.006, p = 0.025), and TMT-B (beta = -0.006, p = 0.002). BMI was positively correlated with serum CRP (unstandardized beta = 0.193, standardized beta = 0.612, p < 0.001) and ESR (beta = 0.039, p < 0.001) levels. Conclusion: We observed a significant negative correlation between BMI and cognitive functioning, and a significant positive correlation between BMI and inflammation in persons with PCC, suggesting a bidirectional interplay between BMI, PCC, and cognitive function; individuals with an elevated BMI may be at a greater risk of developing PCC and/or presenting with greater cognitive deficits mediated by chronic systemic inflammation.