ABO blood group system During the 1930s, connecting blood groups to personality types became popular in Japan and other areas of the world. Studies of this association have yet to confirm its existence definitively. Other popular but unsupported ideas include the use of a blood type diet, claims that group A causes severe hangovers, group O is associated with perfect teeth, and those with blood group A2 have the highest IQs. Scientific evidence in support of these concepts is nonexistent. ABO blood group system The ABO blood group system is used to denote the presence of one, both, or neither of the A and
Jehovah's Witnesses and blood transfusions and other blood-borne infections, or immune system reactions. Many physicians have expressed a willingness to respect patients' preferences and provide bloodless treatment and about 200 hospitals offer bloodless medicine and surgery programs for patients who wish to avoid or limit blood transfusions. Bloodless surgery has been successfully performed in significant procedures including open-heart surgery and total hip replacements. A 2012 study in "JAMA Internal Medicine" concluded that "Witnesses do not appear to be at increased risk for surgical complications or long-term mortality when comparisons are properly made by transfusion status. Thus, current extreme blood management strategies do not appear to