Children later diagnosed with multiple sclerosis had far lower levels of vitamin D than other youngsters, Canadian researchers reported yesterday in studies showing more links between the "sunshine" vitamin and disease.
These were the first studies to show the effects in children, although others have shown that adults who live in northern latitudes, who get less sun exposure, may have a higher risk of MS.
They also support a growing body of studies linking low vitamin D levels with disease, including cancer, heart disease, diabetes and tuberculosis.
Vitamin D, produced by the body when skin is exposed to sunlight, and also found in fatty fish, is added to other foods in many countries. Evidence suggests it helps lower blood pressure and boost the immune system.
Several studies presented at a meeting on MS in Montreal showed that children had low levels of vitamin D when they began to show evidence of the disease.
"Three-quarters of our subjects were below optimal levels for vitamin D," said Heather Hanwell, a graduate student in nutritional sciences at the University of Toronto, who led one study.
Hanwell's team studied 125 kids who had evidence of MS symptoms such as numbness. Twenty of the children were diagnosed with MS within the next year, Hanwell said. Blood tests showed 68 per cent of those children had vitamin D insufficiency.
On average, the children with MS had much lower levels of the vitamin than children who did not experience any other MS-like symptoms.
A study led by Brenda Banwell of Toronto's Hospital for Sick Children showed similar results.
"Seventeen of 19 children who had been diagnosed with MS had vitamin D levels below the target level," Banwell said.
The next step is to see if giving vitamin D supplements prevents MS or helps relieve symptoms, Banwell said. She said it was not clear how lacking vitamin D might be linked with MS.