Iron and glucose homeostasis: new lessons from hereditary haemochromatosis

Excerpt

Interest in the relationship between systemic iron stores and glucose homeostasis has existed since the early descriptions of hereditary haemochromatosis [1, 2]. Diabetes is also prevalent in transfusional iron overload and African iron overload, which resembles haemochromatosis clinically but has a different genetic mechanism. These findings, and studies showing that glucose intolerance in iron overload states can sometimes be prevented or ameliorated by iron removal, have left little doubt that increased tissue iron can contribute to glucose intolerance and diabetes. The actual prevalence of diabetes in haemochromatosis is unknown, with a broad range of estimates reported by different studies. Prevalence assessments have been confounded by selection bias, in that diabetes is considered a diagnostic feature of haemochromatosis. To date, studies of the mechanism(s) of haemochromatosis-associated diabetes have been limited. Thus, discussions of its pathogenesis have drawn heavily on findings in transfusional iron overload, and have been influenced by extensive and elegant studies of type 2 diabetes [3, 4]. In this issue of Diabetologia, McClain et al. provide a combined report of an extensive chart review and a prospective study of newly diagnosed patients with haemochromatosis, to address both the prevalence and mechanism of impaired glucose tolerance and diabetes in this disorder [5]. …