Research Suggests Genetic Predisposition, Not Maternal Deficiencies, Drives Previous Associations with ADHD and Autism
New Norwegian research has investigated whether maternal deficiencies in vitamin D and omega-3 fatty acids (DHA) during pregnancy causally affect offspring neurodevelopment, using Mendelian randomization (MR) and trio-MR analysis. Previous observational studies suggested a link between low maternal nutrient levels and neurodevelopmental traits like ADHD and autism, but these designs couldn’t separate causal effects from genetic confounding. By leveraging genetic data from the Norwegian MoBa cohort, the researchers found that associations between maternal vitamin D and ADHD traits in offspring disappeared once genetic predispositions were accounted for. Furthermore, no evidence supported the maternal effects of vitamin D or DHA on other neurodevelopmental traits or diagnoses. Instead, reverse causation was observed, with genetic predisposition to autism linked to lower vitamin-D levels and ADHD predisposition tied to lower DHA levels. The authors suggest their findings indicate that prior associations were likely driven by shared genetics rather than direct maternal influence, indicating that supplementation during pregnancy is unlikely to impact offspring neurodevelopment significantly.
