Vitamin B-12 status in infancy is positively associated with development and cognitive functioning 5 y later in Nepalese children.

Background: Poor vitamin B-12 (cobalamin) status is widespread in South Asia. Insufficient vitamin B-12 status has been linked to poor neurodevelopment in young children. Objective: We measured the associations between vitamin B-12 status in infancy (2-12 mo) and the development and cognitive functioning in Nepalese children 5 y later. Design: Vitamin B-12 status was assessed in infancy with the use of plasma cobalamin, total homocysteine (tHcy), and methylmalonic acid (MMA). At 5 y of age, we measured development with the use of the Ages and Stages Questionnaire, 3rd edition (ASQ-3), and cognitive functioning by using the Developmental Neuropsychological Assessment, 2nd edition (NEPSY II), in 320 children. In regression models, we estimated the associations between vitamin B-12 status, including a combined indicator of vitamin B-12 status (3cB12) and scores on the ASQ-3 and NEPSY II subtests. Results: All markers of vitamin B-12 status with the exception of plasma cobalamin were significantly associated with the total ASQ-3 scores in the multiple regression models. A 1-unit increase in the 3cB12 score was associated with an increase in the total ASQ-3 score of 4.88 (95% CI: 2.09, 7.68; P = 0.001). Increases in both plasma tHcy and MMA (indicating poorer status) were associated with a decrease in scores on the NEPSY II affect recognition and geometric puzzle subtests. Each unit increment in 3cB12 scores was associated with increases of 0.82 (95% CI: 0.49, 1.14; P < 0.0005), 0.59 (95% CI: 0.10, 1.09; P = 0.020), and 0.24 (95% CI: 0.02, 0.47; P = 0.035) in the affect recognition, geometric puzzle, and block construction scores, respectively. Conclusions: Vitamin B-12 status in infancy is associated with development and performance on social perception tasks and visuospatial abilities at 5 y of age. The long-term effects of poor vitamin B-12 status in infancy need further investigation in randomized controlled trials.