Thiamine deficiency in outpatients at a regional cancer centre in Japan: cross-sectional observational study

Objective To examine the prevalence of thiamine deficiency and its potential risk factors in cancer outpatients. Methods A cross-sectional study of cancer outpatients aged ≥20 years at a regional hospital in Kyoto, Japan (January–February 2022). Thiamine deficiency was defined as ≤23 ng/mL by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Multivariable logistic regression was used to estimate ORs and 95% CIs for potential risk factors for thiamine deficiency. Results A total of 106 patients were included in this study (mean age 68.3 years, 61% female). Of the 106 patients, 27 (25.5%) had low thiamine levels despite the absence of recognised deficiency symptoms. In multivariable logistic regression analysis, the adjusted OR was 4.05 (95% CI 0.88 to 18.60). Conclusions The prevalence of thiamine deficiency was 25.5% among cancer outpatients without recognised symptoms. An association between low dietary intake and thiamine deficiency was suggested, though further large-scale studies are needed to confirm risk factors and guide management strategies.