ABO blood group and social class: a prospective study in a regional blood bank.

STUDY OBJECTIVE The aim of the study was to investigate an association previously reported in a retrospective study between the A phenotype and social classes I and II. DESIGN The study was a prospective survey using a cohort of blood donors. SETTING Participants were donors at a regional blood bank in southern Ireland servicing a population of approximately 380,000. PARTICIPANTS Of 2442 donors considered for inclusion in the study, 21 refused to participate, 33 provided insufficient information, and 184 were excluded because they were not wholly of Irish extraction, leaving a total of 2204 subjects, 64% of whom were male. MEASUREMENT AND RESULTS Occupation, age and birth place were obtained from a short questionnaire given to all potential donors during the study period. Social class was defined according to the United Kingdom Registrar General's criteria. No association between the ABO phenotype and social class could be found, either on the whole sample, or on currently employed persons, or on separate analysis of the sexes. CONCLUSIONS The balance of current evidence is against a variation in ABO distribution by social class designation.