Frequency of lupus in people of African origin.

The epidemiology of SLE in people of African origin clearly varies from one geographical setting to another. It appears to be very rare in West Africa, increasing in frequency in Central and Southern Africa, and of high frequency in America, the Caribbean and Europe. Whether this is predominantly genetic or environmental may be difficult to unravel. Most African-Americans and Caribbeans came from West Africa, where SLE is now rare. This might suggest that environmental factors are more important. However, in the generations since the first Africans arrived in the Americas there has been considerable genetic admixture and this may have lead to increased susceptibility to lupus. Conversely, the increase in SLE may be explained by a reduction in exposure to malaria in most parts of the world except West Africa.