Iron overload and diabetes mellitus. Forest plot illustrating the results of univariable and multivariable logistic models assessing associations between various measures of iron overload duration and degree and development of diabetes mellitus. Multivariable logistic models were controlled for sex, years of life lived since diagnosis of iron overload, and underlying congenital hemolytic anemia (sickle cell disease, beta-thalassemia major, or other congenital hemolytic anemias).