We agree that it is helpful to emphasise that we do not know whether vascular factors are the primary aetiology behind the increased prevalence of dementia in this population. We considered literacy to be a risk, and this (like our earlier study) controlled for education ^{Reference Livingston, Leavey, Kitchen, Manela, Sembhi and Katona1} and found no difference between ethnic groups. Similarly, depression rates in older Black and minority ethnic populations have not been found to be raised; ^{Reference Livingston, Leavey, Kitchen, Manela, Sembhi and Katona1} nor has the prevalence of apolipoprotein 4 when compared with their White counterparts.

However, there are contradictory findings about whether the expression may be the same. ^{Reference Stewart, Russ, Richards, Brayne, Lovestone and Mann2–Reference Murrell, Price, Lane, Baiyewu, Gureje and Ogunniyi5} Thus, although all these factors may relate to the rates of Alzheimer’s dementia, there was no clear evidence to suggest they are responsible for the increased rate in the African–Caribbean group. Finally, there is no evidence that the prevalence of dementia in the participant’s country of birth (Caribbean Islands) is lower than that for the UK. A Delphi consensus study estimated that the rates for Latin America and the Caribbean are at least as high as for Western Europe. ^{Reference Ferri, Prince, Brayne, Brodaty, Fratiglioni and Ganguli6} We agree, however, that more research is needed to consider the possible aetiology and modifiable risk factors.