Child plasma vitamin B12 concentrations and executive functions at age 7-11 years: the GUSTO study

We examined the associations of plasma vitamin B12 concentrations with executive functions (EFs) in children aged 7-11 years from the Growing Up in Singapore Towards healthy Outcomes (GUSTO) cohort.

Plasma vitamin B12 concentrations were measured at age 8 years. Selected subtests from the Developmental Neuropsychological Assessment (NEPSY-II), Wisconsin Card Sorting Test (WCST-64), Delis-Kaplan Executive Function System (D-KEFS), and the Wechsler Intelligence Scale for Children (WISC-V) were used to assess EFs components- inhibition, working memory and cognitive flexibility at 8.5 and 10.5 years. Brain-network functional connectivity (FC) at 7.5 years were acquired through magnetic resonance imaging. Linear regressions adjusting for key confounders (e.g. socio-demographics, growth and lifestyle factors) examined associations of plasma vitamin B12 concentrations at 8 years with FC at 7.5 years, and with EFs at 8.5 and 10.5 years, respectively.

Higher vitamin B12 concentrations at 8 years were associated with better cognitive flexibility at 8.5 years [β (95%CI): 3.23 (0.03, 6.43) for WCST-64 perseverative responses (n = 254)], and better working memory at 10.5 years [0.42 (0.04, 0.8) for WISC-V Letter-Number-Sequencing (n = 304)]; no associations with NEPSY-II and D-KEFS subtests. Higher vitamin B12 concentrations was associated with lower Dorsal Attention and Frontoparietal networks FC (β -0.125, SE: 0.06381, t-value: -2.03, n = 234) linked to better working memory and cognitive flexibility.

Higher vitamin B12 concentrations in later childhood may be beneficial for EFs and brain-networks FC but require confirmation in studies using similar EF tests for comparability, and prospective, longitudinal measure of brain-network FC.