Further evidence of relationship between thiamine blood level and cognition in chronic alcohol-dependent adults: Prospective Pilot Study of an inpatient detoxification with oral supplementation protocol

Background: The relationship between thiamine blood level (TBL) and cognition remains uncertain, including among alcohol-dependent persons (ADP). Aim: To evaluate this relationship during protocol-driven inpatient alcohol detoxification treatment including thiamine supplementation (AD + Th). Methods: Prospective 3-week study with 100 consecutively admitted detoxification-seeking ADP (47.7 +/- 11 years old, 21% females) without superseding comorbidities requiring treatment. TBL and Montreal Cognitive Assessment (MoCA) were measured at admission (t1, pre-AD + Th) and discharge (t3, post-AD + Th). Frontal Assessment Battery (FAB) was performed at t1. AD + Th included abstinence, pharmacological alcohol withdrawal syndrome treatment, and oral thiamine supplementation (200 mg/ day for 14 days). Regression and mediation analyses assessed TBL-cognition relationships. Results: We found no cases of Wernicke Encephalopathy (WE) and only one case of thiamine deficiency. Both MoCA and TBL significantly improved across AD + Th (with medium-to-large effect sizes). At t1, TBL significantly predicted MoCA and FAB sum scores (medium effect sizes; extreme and very strong evi-dence, respectively). The clear TBL-MoCA association disappeared at t3. In multivariate regression and mediation analyses exploring key influential factors of cognition (identified by LASSO regression), the TBL-MoCA interactions did not relevantly change at t1 and t3. Age, serum transaminases, vitamin D levels, drinking-years, and depression score weakly modified the relationship. Conclusion: TBL was a robust predictor of pre-detoxification cognitive impairment, and both TBL and cognition improved significantly during AD + Th (including abstinence) in our ADP population, sup-porting routine thiamine supplementation for ADP, even those at low WE-risk. The TBL-cognition relationship was minimally confounded by age, alcohol-toxicity proxies, mood, and vitamin D levels. (c) 2023 Elsevier Inc. All rights reserved.