JMIR Publications

ABSTRACT

Fat-soluble vitamins (FSVs), including vitamins A, D, E, and K, are essential micronutrients that play critical roles in maintaining human health. Deficiencies or excessive intake of these vitamins can influence clinical decisions regarding nutritional status and the risk of associated diseases. In China, current clinical practice often relies on reference intervals (RIs) derived from Western studies, and no large-scale study has comprehensively analyzed all four FSVs in a healthy Chinese adult population. This study aims to establish RIs for the four FSVs in healthy Chinese adults, providing clinicians with improved tools for assessing vitamin status and preventing related diseases. This cross-sectional study will recruit 100,000 adults aged ≥18 from 20 participating hospitals across China. The data collection process will involve administering a questionnaire and a comprehensive physical examination, including blood sample collection for laboratory testing. FSVs levels in blood samples will be quantitatively analyzed using liquid chromatography-tandem mass spectrometry (LC-MS/MS). Rates will be compared using χ² test or Fisher test. Nested ANOVA will be employed to evaluate reference values across subgroups, and RIs will be determined as the central 95% range. The 2.5th and 97.5th percentiles of reference values for each final reference group will be calculated using non-parametric methods to define the lower and upper reference limits, respectively.