Medicina (Kaunas, Lithuania)Jun 26, 2026

Clinical and Inflammatory Signs Linked to Thinking Problems in Long COVID Over Two Years

Long Covid Weekly Brief ↗PubMed ↗DOI ↗OA ↗

Updated Jun 27, 2026

Abstract

In a study of 108 long COVID patients, cognitive decline was significantly associated with COVID-19 severity and autoimmune conditions.

Significant predictors of cognitive decline in patients with MoCA scores ≥23 included severe COVID-19, autoimmune comorbidities, and elevated neutrophil-to-lymphocyte ratio (NLR).
For those with MoCA scores <23, independent predictors of cognitive decline were diabetes mellitus, autoimmune comorbidities, and NLR.
Serum vitamin D levels were significantly associated with MoCA scores in both cognitive groups.
Findings suggest that COVID-19 severity, autoimmune conditions, NLR, and vitamin D may be important risk factors for neurocognitive decline in long COVID.

Simplified

Background and Objectives: Neurological complications of SARS-CoV-2 infection frequently impair patients' long-term quality of life. This study aimed to identify clinical and laboratory risk factors-including inflammatory markers and micronutrients-for the occurrence or worsening of neurocognitive disorders in long COVID patients. Materials and Methods: In this prospective observational study, patients presenting with long COVID neurological manifestations were stratified by baseline MoCA score into two groups (≥23 and <23). Clinical, laboratory (inflammatory markers, 25-hydroxy vitamin D, vitamin B12, folic acid), and neuroimaging assessments (global cortical atrophy scale, Fazekas score) were performed over 24 months. Propensity score matching (PSM) for age, gender, and neurological comorbidities yielded 54 patients per group. Results: In the MoCA ≥ 23 group, significant predictors of cognitive decline included severe COVID-19 (OR = 2.211, 95% CI = 1.819-5.973, p = 0.012), autoimmune comorbidities (OR = 1.676, 95% CI = 1.191-2.390, p = 0.043), and elevated neutrophil-to-lymphocyte ratio (NLR; OR = 1.586, 95% CI = 1.431-2.122, p = 0.011). In the MoCA < 23 group, independent predictors were diabetes mellitus (OR = 3.021, 95% CI = 2.65-14.004, p = 0.016), autoimmune comorbidities (OR = 4.987, 95% CI = 1.412-6.033, p = 0.021), and NLR (OR = 5.944, 95% CI = 2.353-19.321, p = 0.015). Serum vitamin D levels were significantly associated with MoCA scores in both groups. Conclusions: COVID-19 severity, autoimmune comorbidities, NLR, and serum vitamin D represent key risk factors for neurocognitive decline in long COVID, highlighting potential targets for early intervention.