Prenatal Vitamin D Levels in Maternal Sera and Offspring Specific Learning Disorders

Abstract

<p>Recent evidence has suggested potential harmful effects of vitamin D deficiency during<br>pregnancy on offspring brain development, for example, elevated risks for neuropsychiatric disorders.<br>Findings on general cognition and academic achievement are mixed, and no studies have examined<br>the effect of prenatal 25-hydroxyvitamin D (25(OH)D) levels on diagnosed specific learning disorders,<br>which was the aim of this study. We examined a nested case–control sample from the source cohort<br>of all singleton-born children in Finland between 1996 and 1997 (n = 115,730). A total of 1607 cases<br>with specific learning disorders (mean age at diagnosis: 9.9 years) and 1607 matched controls were<br>identified from Finnish nationwide registers. Maternal 25(OH)D levels were analyzed from serum<br>samples collected during the first trimester of pregnancy and stored in a national biobank. Conditional<br>logistic regression was used to test the association between maternal 25(OH)D and offspring specific<br>learning disorders. There were no significant associations between maternal 25(OH)D levels and<br>specific learning disorders when vitamin D was examined as a log-transformed continuous variable<br>(adjusted OR 0.98, 95% CI 0.82–1.18, p = 0.84) or as a categorical variable (25(OH)D < 30 nmol/L:<br>adjusted OR 1.03, 95% CI 0.83–1.28, p = 0.77 compared to levels of >50 nmol/L), nor when it was<br>divided into quintiles (adjusted OR for the lowest quintile 1.00, 95% CI 0.78–1.28, p = 0.99 compared<br>to the highest quintile). This study found no association between low maternal 25(OH)D in early<br>pregnancy and offspring specific learning disorders.<br></p>