Plasma vitamin B 12 concentration is positively associated with cognitive development in healthy Danish 3-year-old children: the SKOT cohort studies.

Adequate vitamin B (B) and folate concentrations are essential for neural development in early childhood, but studies in well-nourished children are lacking. We investigated the relation between plasma B and folate at 9 and 36 months and psychomotor development at 36 months in well-nourished Danish children. Subjects from the SKOT cohorts with B measurement and completed Ages and Stages Questionnaire, 3rd edition (ASQ-3) at 36 months were included ( 280). Dietary intake, B and folate concentrations were collected at 9 and 36 months, and ASQ-3 was assessed at 36 months. Associations between B and folate at 9 and 36 months and ASQ-3 were analysed using regression models. Associations between diet and B were also investigated. No children had insufficient B (<148 pmol/l) at 36 months. B at 36 month was positively associated with total ASQ-3 corresponding to an increase of 100 pmol/l B per 1·5 increase in total ASQ-3 score ( = 0·019) which remained significant after adjustment for potential confounders including 9 months values. B at 9 months or folate at any time point was not associated with total ASQ-3. Intake of milk products was associated with B at 36 months ( = 0·003) and showed a trend at 9 months ( = 0·069). Intake of meat products was not associated with B. In conclusion, B was positively related to psychomotor development at 3 years in well-nourished children, indicating that the impact of having marginally low B status on psychomotor development in well-nourished children should be examined further.