Determinants of Serum Biotin (Vitamin B7) Concentrations: Influence of Age, Sex, and Season in a Large Population Cohort: A Retrospective Cross-Sectional Study

Background/Objectives: Population-level data on serum biotin (vitamin B7), an essential carboxylase cofactor, remain limited, particularly in Middle Eastern populations. We described serum biotin distribution and examined demographic and seasonal correlates in a large Saudi cohort.

Methods

This retrospective cross-sectional study included 11,735 adults (79.0% female; mean age 36.5 ± 11.8 years) with serum biotin measurements from an institutionally supported outpatient clinical/laboratory testing program in Riyadh. Serum biotin was measured by competitive enzyme-linked immunosorbent assay (ELISA); results above the measuring range were recorded at its upper limit (1100 ng/L). Associations were evaluated using non-parametric tests and multivariable regression, including regression for censored data.