Background The relationship between thiamine blood level (TBL) and cognition remains uncertain including amongst 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 evidence, 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, supporting routine thiamine supplementation for ADP, even those at low WE-risk. TBL-cognition relationship was minimally confounded by age, alcohol-toxicity proxies, mood, and vitamin D levels.
Clinical trials registration https://osf.io/b54eh/