London, Oct 8 (IANS): Mothers who take vitamin D during pregnancy may reduce the risk of their children developing attention-deficit hyperactivity disorder (ADHD) -- one of the most common neurobehavioural disorders.

A study, which monitored 1,233 children, showed that mothers who had taken vitamin D, and had a vitamin D level (25OHD) in their umbilical blood over 25 nmol/L, had children with lower ADHD scores.

The higher the level of the vitamin D in the umbilical blood, the lower were the symptoms of ADHD at the age of two-and-a-half years.

"And for every 10 nmol/L increase in the vitamin D concentration in umbilical blood, the risk of being among the 10 per cent highest score on the ADHD symptom scale fell by 11 per cent," said Niels Bilenberg, Professor at the University of Southern Denmark.

Previously, it was not known that the link between vitamin D and early ADHD symptoms could be identified at such an early age.

However, the study offers no explanation as to how vitamin D can protect against ADHD, but other studies have shown that it plays an important role in the early development of the brain, the researchers observed.

The findings were published in The Australia & New Zealand Journal of Psychiatry.