When reporting the ethnicity of participants in studies, use the terminology used in the studies. If the terminology is obviously inaccurate or inappropriate, first mention the terminology used in the study, and follow it by the correct terminology in parentheses (e.g. 'The study included 843 Caucasian participants (understood to be white participants)'). When mentioning ethnic groups in other sections of the review use an acceptable contemporary term. There is no simple consensus on names, so where possible use precise descriptions rather than catch-all terms, being sure to distinguish between ethnicity and nationality (e.g. Croats versus Croatians).
These resources may be helpful: