[dijit]

That is one hypothesised cause for the disparity, social factors in those cases need to be controlled for.

A better discussion is around sickle cell anaemia[0] which is exclusively carried by people of African or Afro-Caribbean descent.

[0]: https://en.wikipedia.org/wiki/Sickle_cell_disease

[PartiallyTyped]

That's a better example, thank you. Reminded me that I know quite a few people with Thalassemia/Mediterranean anemia.

[pessimizer]

Sickle cell disease is exclusively caused by genetics, not race. The vast majority of people of African or Afro-Caribbean descent aren't carriers, so have the same likelihood as everyone else who is not a carrier to develop it.