Studies have observed that vitamin D plays a significant role in the development of the central nervous system, with some data supporting a correlation between vitamin D deficiency during pregnancy and offspring attention-deficit/hyperactivity disorder (ADHD) symptoms per parent or teacher ratings. Studies have not examined the relationship between early pregnancy 25-hydroxyvitamin D (25[OH]D) levels and the risk of an ADHD diagnosis in offspring. In this nationwide, population-based, case-control study, the researchers explored how 25(OH)D levels during early pregnancy impact offspring ADHD risk.
Patients with ADHD who were born between 1998 and 1999 (n=1,067) and diagnosed per the International Classification of Diseases were identified using Finnish registers. These patients were matched 1:1 to a control group. Levels of 25(OH)D were determined with a quantitative immunoassay from maternal sera that was gathered during the first trimester and stored in the national biobank. The correlation between maternal 25(OH)D and offspring ADHD was analyzed using conditional logistic regression.
Decreasing log-transformed maternal 25(OH)D levels were predictive of offspring ADHD in unadjusted analyses (odds ratio [OR], 1.65; 95% confidence interval [CI], 1.33-2.05; P<0.001) and when adjusting for the mother’s socioeconomic status and age (OR, 1.45; 95% CI, 1.15-1.81; P=0.002). When evaluating by quintiles of maternal 25(OH)D levels in the lowest quintile compared with the highest, the adjusted OR for offspring ADHD was 1.53 (95% CI, 1.11-2.12; P=0.010). The study authors noted that the data presented a correlation between low prenatal 25(OH)D levels and an increased risk for offspring ADHD.