Abstract
Multiple sclerosis has been reported to be very uncommon in the West Indies. In previous studies immigrants from the West Indies resident in Greater London had only one-eighth the likelihood of being diagnosed in hospital as having multiple sclerosis compared with those born in the United Kingdom. No studies of the incidence and prevalence of multiple sclerosis were available for London or South East England but there is evidence that it is much the same as occurs in Ireland. In the age groups studied the United Kingdom-born children of West Indian immigrants had an incidence and prevalence of probable multiple sclerosis of the same order as has been reported in Northern Ireland and in the Irish Republic. Although there is evidence that genetic factors play a part, our findings are strong evidence that the cause of the disease is mainly environmental and is therefore potentially preventable.