Dr. Solomon, who wasn't involved in the Swedish study, recommends his patients take 2, 000 to 4, 000 international units a day of vitamin D.

WSJ: Swedish Study Links Multiple Sclerosis to Vitamin D Levels

In his study they tend to use terms which are not in themselves abusive, but take on an extra dimension when the group in question is stigmatised.

BBC: Refugee: today's playground insult?