People with high levels of vitamin D in their blood have shown a lower risk of developing multiple sclerosis, according to results of a Swedish study released Monday.

The new study adds to a growing body of research suggesting a link between vitamin D and MS, an autoimmune disease that affects the brain and spinal cord that is believed to afflict more than a quarter-million Americans. The research will be published in Tuesday's edition of the medical journal Neurology.

Vitamin...