A new Australian study suggests that an adequate maternal vitamin D status during pregnancy is important for optimal language development in offspring.
Over a 2-year period, investigators measured serum 25(OH)-vitamin D concentrations in venous blood samples drawn from 743 pregnant white women at 18 weeks' gestation. They divided maternal vitamin D concentration levels into 4 quartiles ranging from the lowest at 46 nmol/L or less (quartile 1) to the highest at 72 nmol/L or more (quartile 4). Behavior was measured with the Child Behavior Checklist at 2, 5, 8, 10, 14, and 17 years. Language was assessed with the Peabody Picture Vocabulary Test at 5- and 10-year follow-ups.
At 5 years, investigators saw a significant linear-by-linear association between vitamin D quartiles and the proportion of offspring with language difficulties, with the proportion of mothers who had offspring with mild or moderate to severe language difficulties decreasing as maternal vitamin D levels during pregnancy increased. Women in quartile 1 were more than twice as likely as women in quartile 4 to have a child with clinically significant language difficulties, even after accounting for a range of confounding variables.
For this study, investigators used blood samples collected from 1989 to 1991 and developmental data collected since. Some evidence exists that vitamin D levels in the US population dropped between 1988 and 2004 (Arch Intern Med. 2009;169:626-632). Should we expect to see an increase in language impairment over the next several years? We still have a lot to learn about vitamin D. -Michael Burke, MD
DR BURKE, section editor for Journal Club, is chairman of the Department of Pediatrics at Saint Agnes Hospital, Baltimore, Maryland. He is a contributing editor for Contemporary Pediatrics. He has nothing to disclose in regard to affiliations with or financial interests in any organization that may have an interest in any part of this article.