Certain blood groups, like type B, are more common among people from the African, Caribbean and South Asian communities.

I'm glad this singer is urging black and Asian people to give blood because, as the mail says "some medical conditions requiring regular blood transfusions, like sickle cell anemia,have higher prevalence within these communities".

Actually the mail is bending the truth somewhat as, only black and south Asians(especially blacks) suffer from sickle cell.

Who Gets SCDs? http://www.mcr-sicklecellandthalassaemia.co.uk/sickle_disease.html
"The different kinds of SCD and the different traits are found mainly in people whose families come from Africa, the Caribbean, the Eastern Mediterranean, Middle East and Asia.* In Britain SCD is most common in people of African and Caribbean descent (at least 1 in 10-40 have sickle cell trait and 1 in 60-200 have SCD).

It is estimated there are over 6,000 adults and children with SCD in Britain at present. There are other inherited conditions that mainly affect other groups, e.g. Cystic Fibrosis in Europeans, and Tay-Sachs disease in Jewish people."