Assessment of iron overload impact over type 1 diabetes mellitus

Objective: To assess the relation between iron overload and age at diagnosis, insulin secretion and glycemic control on a cohort of patients with type 1 diabetes. Methods: Caucasian patients with type 1 diabetes and no other significant comorbidities were included. They were characterized on what concerns to gender, age at diagnosis, current age, disease's duration, C-peptide, A1C, transferrin saturation and ferritin. Correlations among different parameters were sought. Patients with maintained iron kinetics abnormalities underwent HFE testing. Results: We included 166 patients. The average age at diagnosis was of 17.1 +/- 11.1 years, current age of 30.8 +/- 12.7 years and disease's duration of 13.4 +/- 9.1 years. The laboratory study revealed an average C-peptide of 0.16 +/- 0.33 ng/mL, A1C of 9.0 +/- 2.0%, transferrin saturation of 29.0 +/- 11.4% and ferritin of 84.0 +/- 81.5 ng/mL. C-peptide correlates inversely with disease's duration and directly with ferritin and transferrin saturation. Ferritin correlates directly with age at diagnosis and current age. An inverse correlation between A1C and current age was attained. Conclusions: Iron overload is related with greater maintenance of insulin secretion and older age at diagnosis, without harmful influence over glycemic control. Considering that iron overload may be an environmental trigger for late-onset type 1 diabetes, iron kinetics evaluation in patients with type 1 diabetes might be helpful to settle an early diagnosis of hemochromatosis and therefore ensure preservation of quality of life in these patients. (C) 2015 Sociedade Portuguesa de Endocrinologia, Diabetes e Metabolismo. Published by Elsevier Espana, S.L.U. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).