Maternal Diet Quality and Multivitamin Intake During Pregnancy Interact in the Association with Offspring Neurodevelopment at 2 Years of Age.

To comprehensively evaluate the interaction between diet quality and multivitamin intake during pregnancy on offspring neurodevelopment. This analysis was grounded in mother-child dyads from the 3D Cohort Study in Quebec, Canada. Among the 2366 participants initially enrolled in the 3D study, 1535 women successfully completed the 3-day food record during 20-24 weeks of gestation. A Canadian adaptation of the Healthy Eating Index (HEI-C) 2010 was used to quantify diet quality. The total HEI-C score was dichotomized into low and high diet quality by median split. Cognitive and motor development in childhood were assessed using the Bayley Scales of Infant and Toddler Development, Third Edition (Bayley-III). Language abilities were measured using the toddler short-form version of the MacArthur-Bates Communicative Development Inventories (MCDI) questionnaire, administered in either English or French. After excluding participants with missing covariate data, cognitive, motor, and language development scores at 2 years of age were available for 1066, 1040, and 981 children, respectively. Multiple linear regression models were employed to calculate adjusted effect estimates. The interaction on an additive scale was assessed by incorporating a product term into the linear regression model. Statistically significant interactions were detected between diet quality and multivitamin intake in relation to the cognitive and language development outcomes of the offspring (interaction -values were 0.018 and 0.023, respectively). The lowest cognitive and language scores were observed in the group of women who neither took multivitamins nor maintained a high-quality diet. Among women not taking multivitamins, a high-quality diet was associated with improved offspring cognitive and language scores (mean difference [95% CI] = 4.2 [0.1, 8.2], = 0.04; and 11.3 [3.1, 19.5], = 0.01, respectively). However, among women taking multivitamins, no such associations were identified. Conversely, in participants with a low-quality diet, multivitamin intake was associated with a 3.0-point increase in cognitive composite scores (95% CI: 0.3, 5.8, = 0.03), but this was not the case for those with a high-quality diet. No statistically significant interactions were observed between maternal diet quality and multivitamin intake for motor development outcomes. Adequate nutritional supply during pregnancy, achieved either through a high-quality diet or multivitamin supplementation, is fundamental for the neurodevelopment of children.