Thiamine status in Belgian adults assessed by volumetric absorptive microsampling: a nation-wide cross-sectional...

Nutritional intake in population studies is typically estimated via food consumption surveys. However, because dietary intake does not always reflect the actual nutritional status, additional biomarker data are essential. Volumetric absorptive microsampling (VAMS) offers a convenient tool for large-scale (dried) whole blood collection, enabling direct biomarker measurement and thereby also offering a potential improvement in nutritional assessment.

The study aims to determine thiamine status in Belgian adults via microsampling-at-home and to evaluate the feasibility of microsampling for the purpose of large-scale biomarker data collection.

Capillary VAMS samples from 656 of the 1047 adults participating to the Finger prick study as part of the Belgian National Food Consumption Survey 2022-2023 (a nation-wide cross-sectional study) were analyzed. Thiamine diphosphate (TDP) concentrations were measured using a previously validated liquid chromatography-tandem mass spectrometry method. Habitual thiamine intake was assessed to estimate the proportion of individuals meeting the average requirement (AR) for thiamine and this was compared with the proportion of individuals with TDP concentrations within the healthy reference range.

An overall successful participation-to-analysis rate of 63% (656/1047) was obtained with insufficient VAMS sample quality being responsible for 16% of the excluded samples (167/1047). The median TDP concentration derived for the adult Belgian population was 98.5 nmol/L [95% confidence interval (CI): 96.6, 100.8 nmol/L], with 11% (corresponding to the 11th percentile) having a TDP concentration below the lower limit of the healthy reference range (70-180 nmol/L). Dietary intake data indicated that <1% (mean of 0.24%, 95% CI: 0.08, 0.39%) of adults had a thiamine intake below the AR of 0.072 mg/MJ.

Although nearly all Belgian adults met thiamine intake requirements, 11% showed biomarker concentrations indicative of thiamine insufficiency, underscoring the importance of biomarker-based nutritional assessments. This study also demonstrates that at-home VAMS microsampling is a feasible and convenient tool for large-scale biomarker collection.