Low-pigment skin type and predisposition for development of type I diabetes

To ascertain whether skin pigmentation type and sensitivity to ultraviolet (UV) light are associated with susceptibility to type I (insulin-dependent) diabetes, 55 type I diabetic patients were examined, 38 new-onset and 17 long-term cases. They were compared to 72 control subjects of the same geographic region and nationality. To evaluate the individual skin pigmentation type, a standardized questionnaire was developed. Reactivity to UV light was determined by a stepwise-graded UV irradiation. Significantly more diabetic patients in southern Germany had blue eyes than nondiabetic control subjects (55 vs. 26%, P less than 0.01), and significantly more diabetic patients had a low-pigment eye color (blue or green) than control subjects (66 vs. 38%, P less than 0.01). In addition, more fair skin color was noted among diabetic versus control subjects (84 vs. 60%, P less than 0.01). In response to UV irradiation, diabetic patients more often showed an increased UV-light sensitivity than control subjects (83 vs. 23%, P less than 0.001). The relative risk for susceptibility to type I diabetes in subjects with low-pigment eye color was 3.1, in subjects with fair skin type 3.4, and in subjects with increased UV-light sensitivity 5.8. The highest risk for the development of diabetes was seen in subjects who had low-pigment eye color and/or increased UV-light sensitivity (95 vs. 51%, P = 0.00002, odds ratio 17.4). We conclude that a low-pigment skin type may predispose for the development of type I diabetes.