Feb 16 (Reuters) - Mothers who had low vitamin D levels while they were pregnant are more likely to have a child with a language impairment than mothers who had higher levels of the vitamin, according to an Australian study.
While the study, published in Pediatrics, did not show that low levels of the vitamin itself caused the issues, researchers said it pointed to a "plausible association" that warranted more attention.
Earlier studies had shown some links between low vitamin D during pregnancy and problems in children such as weaker bones, asthma and poor growth, said Andrew Whitehouse, lead author of the study, who was based at the University of Western Australia.
"The effects of lower maternal vitamin D levels on the developing offspring is not fully understand," he added.
Sunlight is a primary source of vitamin D.
Twenty years ago Whitehouse and his colleagues measured the vitamin D levels of more than 700 women who were about halfway through their pregnancy, seeking to determine whether levels of the vitamin might have anything to do with children's later behavioral and language development.
Five and 10 years later, they tested the children of these mothers to measure their behavioral and emotional development, and language skills.
The researchers split the mothers into four groups, from lowest to highest vitamin D levels, and found that the risk of having a child with emotional or behavioral issues was the same for each group.
When they looked at language skills, though, the team found that mothers in the group with the lowest vitamin D levels were more likely to have a child with a language impairment, as determined from scores on a vocabulary test, than mothers in the highest vitamin D category.
For instance, about 18 percent of mothers in the lowest group had a child with a language issue at age 10, compared to roughly eight percent of mothers in the highest group.
"The logical thought is that maternal vitamin D insufficiency during pregnancy is affecting the normal course of brain development," Whitehouse told Reuters Health by email.
"If vitamin D insufficiency during prenatal life is a cause of childhood language difficulties -- and this still needs to be determined conclusively -- then vitamin D supplementation of pregnant women may be an important next step."
He made clear, though, that the study does not show a cause-and-effect relationship between vitamin D and language problems.
Other researchers said that one factor that will be important to tease out in future studies is whether obesity might be involved.
"We know that obesity before pregnancy is associated with poor vitamin D status in pregnancy, and we know that obese moms are more likely to have children with developmental delays and cognitive impairments," said Lisa Bodnar, a professor at the University of Pittsburgh who was not involved in the study.
She added that it will be important for future studies to determine if vitamin D is in fact to blame for the language impairments, because it's a simple problem to fix with supplements. SOURCE: bit.ly/xyuOsR (Reporting from New York by Kerry Grens at Reuters Health; editing by Elaine Lies)