Plasma 25-hydroxyvitamin D is positively associated with folate and vitamin B12 levels in adolescents

Abstract Vitamin D affects the absorption of folate in vitro, and perhaps of vitamin B12 (B12). However, epidemiological studies on the association of vitamin D with folate and B12 are inconclusive. We hypothesized a positive association of plasma 25-hydroxyvitamin D [25(OH)D] with folate and B12 levels in adolescents. This hypothesis was tested in a cross-sectional study of healthy adolescents (11–16 years-old; n = 1416), selected from public middle schools from across Kuwait, using stratified multistage cluster random sampling. Plasma 25(OH)D was measured by LC–MS/MS. Serum B12 and total folate in hemolyzed whole blood were analyzed with commercial kits; RBC and plasma folate were calculated from total folate. Data on potential confounders were collected from the parents and adolescents. In univariable model, 25(OH)D as a continuous variable was positively associated with each of total, RBC, and plasma folate (P