ABO system is not associated with proximal femoral fracture pattern in Southern Italy

Introduction: The mechanism that leads to a given fracture pattern is not understood. Heredity could act in this field through the ABO system. We investigated the relationship between ABO blood system and hip fracture pattern in a population from Southern Italy. Methods: Hip fractures were identified through a registry evaluation of the activity of a level I Hospital, and subsequently classified in 'intracapsular' or 'extracapsular' according to their anatomical location. Information on these patients' ABO blood type was collected and compared with general population data from the report on blood donors of the Salerno division of Italian Blood Volunteers Association (AVIS). Results: 590 hip fractures were included (414 extracapsular, 176 intracapsular) and compared with 709 blood donors. Fractured patients presented a blood group A more often and blood group O less often than the AVIS population (p A vs. non-A = 0.0033; p O vs. non-O = 0.0024). None of the ABO blood groups were associated with fracture pattern (p O vs. non-O = 0.5858, p A vs. non-A = 0.409; p B vs. non-B = 0.253; p AB vs. non-AB = 0.212). The rhesus factor was not associated the fracture pattern (p = 0.34). Conclusions: The ABO blood type could play a role as a risk factor for proximal femoral fractures, but in our population its relevance in influencing the fracture pattern is unclear.