OBJECTIVE: Recently, we reported increased cardiovascular disease mortality among supplemental vitamin C users with type 2 diabetes in a prospective cohort study. Because vitamin C may cause oxidative stress in the presence of redox active iron, we hypothesized that non-transferrin-bound iron (NTBI), a form of iron susceptible to redox activity, may be present in patients with type 2 diabetes. RESEARCH DESIGN AND METHODS: We measured serum NTBI levels using high-performance liquid chromatography in 48 patients with known diabetes (at least 5 years duration since diagnosis), 49 patients with newly diagnosed diabetes, and 47 healthy control subjects (frequency matched on age and sex). RESULTS: NTBI was commonly present in diabetes: 59% in newly diagnosed diabetes and 92% in advanced diabetes. Mean NTBI values varied significantly between the three groups, with the highest values being observed in patients with known diabetes and the lowest in the control subjects (0.62 +/- 0.43 vs. 0.24 +/- 0.29 vs. 0.04 +/- 0.13 micromol/l Fe). Serum total iron or percent transferrin saturation were very similar among the three groups, yet NTBI was strongly associated with serum total iron (r = 0.74, P < 0.01) and percent transferrin saturation (r = 0.70, P < 0.01) among the patients with known diabetes. CONCLUSIONS: Consistent with our hypothesis, these data demonstrate the common existence of NTBI in type 2 diabetic patients with a strong gradient with severity. Prospective cohort studies are required to clarify the clinical relevance of increased NTBI levels.
OBJECTIVE: Recently, we reported increased cardiovascular disease mortality among supplemental vitamin C users with type 2 diabetes in a prospective cohort study. Because vitamin C may cause oxidative stress in the presence of redox active iron, we hypothesized that non-transferrin-bound iron (NTBI), a form of iron susceptible to redox activity, may be present in patients with type 2 diabetes. RESEARCH DESIGN AND METHODS: We measured serum NTBI levels using high-performance liquid chromatography in 48 patients with known diabetes (at least 5 years duration since diagnosis), 49 patients with newly diagnosed diabetes, and 47 healthy control subjects (frequency matched on age and sex). RESULTS:NTBI was commonly present in diabetes: 59% in newly diagnosed diabetes and 92% in advanced diabetes. Mean NTBI values varied significantly between the three groups, with the highest values being observed in patients with known diabetes and the lowest in the control subjects (0.62 +/- 0.43 vs. 0.24 +/- 0.29 vs. 0.04 +/- 0.13 micromol/l Fe). Serum total iron or percent transferrin saturation were very similar among the three groups, yet NTBI was strongly associated with serum total iron (r = 0.74, P < 0.01) and percent transferrin saturation (r = 0.70, P < 0.01) among the patients with known diabetes. CONCLUSIONS: Consistent with our hypothesis, these data demonstrate the common existence of NTBI in type 2 diabeticpatients with a strong gradient with severity. Prospective cohort studies are required to clarify the clinical relevance of increased NTBI levels.
Authors: Clara Podmore; Karina Meidtner; Matthias B Schulze; Robert A Scott; Anna Ramond; Adam S Butterworth; Emanuele Di Angelantonio; John Danesh; Larraitz Arriola; Aurelio Barricarte; Heiner Boeing; Françoise Clavel-Chapelon; Amanda J Cross; Christina C Dahm; Guy Fagherazzi; Paul W Franks; Diana Gavrila; Sara Grioni; Marc J Gunter; Gaelle Gusto; Paula Jakszyn; Verena Katzke; Timothy J Key; Tilman Kühn; Amalia Mattiello; Peter M Nilsson; Anja Olsen; Kim Overvad; Domenico Palli; J Ramón Quirós; Olov Rolandsson; Carlotta Sacerdote; Emilio Sánchez-Cantalejo; Nadia Slimani; Ivonne Sluijs; Annemieke M W Spijkerman; Anne Tjonneland; Rosario Tumino; Daphne L van der A; Yvonne T van der Schouw; Edith J M Feskens; Nita G Forouhi; Stephen J Sharp; Elio Riboli; Claudia Langenberg; Nicholas J Wareham Journal: Diabetes Care Date: 2016-02-09 Impact factor: 19.112