Studies evaluating the relationship between soluble transferrin receptor (sTfR), a biomarker inversely related to body iron stores, and risk of type 2 diabetes mellitus (T2DM) are scarce and inconclusive. Furthermore, sTfR concentrations have been observed to be significantly higher in obese than in non-obese individuals. Therefore, the aim of the present study was to assess the relationship between sTfR and the risk of T2DM in obese and non-obese subjects.
A nested case-control study of 153 cases of newly diagnosed diabetic subjects, 73 obese and 80 non-obese, and 306 individually matched-controls, 138 obese and 166 non-obese, who did not develop T2DM for a median 6-year follow-up (interquartile range: 3.9-6.5) was conducted using data from the PREDIMED (PREvention with MEDiterranean Diet) cohort (http://www.controlled-trials.com/ISRCTN35739639). Cases and controls were matched for age (≤67 vs. >67years), gender, dietary intervention group, and BMI (≤27 vs. >27kg/m(2) ).
Waist circumference is the main determinant of sTfR concentrations in the whole sample (β=0.476, P<0.001), in the obese (β=0.802, P<0.001) and the non-obese (β=0.455, P=0.003). Furthermore, sTfR is directly associated with the risk of T2DM in obese individuals (OR=2.79; 95% CI:1.35-5.77, P=0.005) and inversely associated in non-obese individuals (OR=0.40; 95% CI:0.20-0.79, P=0.015).
The association between sTfR levels and risk of T2DM in a population at high cardiovascular risk depend on the presence or absence of obesity. While in non-obese subjects elevated sTfR levels are associated with a decreased risk of developing T2DM, in obese subjects the risk increases. This suggests that obesity alters the relationship between sTfR and T2DM incidence. This article is protected by copyright. All rights reserved.