Prevalence of vitamin B12 deficiency and its association with cognitive performance among adolescents

Background

Vitamin B12 is required for one-carbon metabolism, myelin maintenance and normal neurologic function.Adolescence is a period of rapid growth and increasing academic demands, yet Indian data linking vitamin B12 status withcognitive performance remain limited. The study is designed to estimate the hospital-based prevalence of vitamin B12deficiency among adolescents and examine its association with cognitive performance and selected nutritional factors.Materials and Methods: A cross-sectional study was conducted in the Department of Pediatrics, Apollo Institute ofMedical Sciences and Research, Hyderabad, from June 2025 to May 2026. Adolescents aged 10-19 years were enrolled.Serum vitamin B12 was measured by chemiluminescence. Deficiency was defined as <200 pg/mL, borderline status as 200-299 pg/mL, and sufficient status as >=300 pg/mL. Cognitive performance was assessed using age-standardized Raven'sStandard Progressive Matrices and a standardized Digit Span task. A composite cognitive z-score was derived. Groupdifferences were tested with chi-square and one-way ANOVA, and multivariable logistic regression was used to identifyfactors associated with lower cognitive performance.