Suspected autoimmune disorders and left-handedness: evidence from individuals with diabetes. Crohn's disease and ulcerative colitis.

This study tested the theory that left-handedness is associated with certain disorders that may have an autoimmune aetiology. To accomplish this, we compared the handedness patterns of people with either Type I or Type II diabetes, Crohn's disease, or ulcerative colitis with a normal control group. Consistent with earlier findings, a significantly higher incidence of left-handedness was observed in people with either Crohn's disease or ulcerative colitis. In addition, there was evidence that males with Type I diabetes were more likely to be left-handed than males with Type II diabetes.