Hepatic iron stores are increased as assessed by magnetic resonance imaging in a Chinese population with altered glucose homeostasis

Abstract

Background: Emerging scientific evidence has disclosed a correlation between iron metabolism and type 2 diabetes (T2D). Objective: The objective of this study was to test the hypothesis that body iron stores are higher in a Chinese population with altered glucose homeostasis. Design: Serum iron, ferritin, and soluble transferrin receptor concentrations were measured in 298 subjects, including 70 subjects with normal glucose tolerance (NGT group), 60 subjects with prediabetes (prediabetes group), and 168 subjects with T2D (T2D group). Hepatic iron stores in 88 subjects were assessed by using a magnetic resonance imaging (MRI) T2*gradient-recalled-echo technique. A general linear model ANOVA was performed for comparisons between groups after adjustment for age and BMI. Stepwise multiple linear regression analysis was used to identify factors associated with the MRI-estimated hepatic iron concentration (M-HIC). Results: Mean (±SD) M-HIC and R2*values in the prediabetes and T2D groups were significantly higher than in the NGT group (M-HIC: 40.6 ± 8.6 and 39.3 ± 10.7 μmol/g compared with 27.8 ± 9.1 μmol/g; R2*values: 47.9 ± 11.9 and 47.3 ± 11.5 s -1 compared with 34.9 ± 7.0 s -1; all P < 0.01). No significant difference was shown in M-HIC and R2*values between prediabetes and T2D groups. The M-HIC independently contributed to 43.3% of the glycated hemoglobin variance after adjustment for main clinical indexes (P < 0.001). The proportions of subjects with mild hepatic iron overload in the NGT, prediabetes, and T2D groups were 12.5%, 70.6%, and 63.6%, respectively. Conclusions: To our knowledge, our findings provide novel evidence to support the hypothesis of a mild iron overload in patients with prediabetes and T2D. A cohort study concerned with the effect of the attenuation of excess iron on glucose metabolism in a prediabetic population is warranted. © 2011 American Society for Nutrition.