Table 1.
Characteristics of included studies reporting on hepcidin levels and iron profiles in patients with type 2 diabetes (T2D) (n = 11).
| Study | Country | Study size | Male, n (%) | Age (years) BMI [kg/m2] |
Reported effect measures of iron metabolism in serum | Main findings |
|---|---|---|---|---|---|---|
| Jiang et al., 2011 [6] | China | 64 participants (34 T2D and 30 controls) | 35 (55%) | T2D (60.88 ± 10.99) [25.72 ± 3.28] Control (60.19 ± 6.74) [22.52 ± 2.44] |
Hepcidin, haemoglobin, ferritin and erythropoietin | The levels of hepcidin, ferritin and erythropoietin were elevated in T2D patients, whilst haemoglobin levels were lower than in healthy controls. The levels of hepcidin positively correlated with ferritin levels among T2D individuals and the controls. |
| Zheng et al., 2011 [10] | China | 238 participants (168 T2D and 70 controls) | 77 (32%) | T2D (62.7 ± 8.7) [25.4 ± 3.65] Control (52.94 ± 8.03) [24.28 ± 1.25] |
Hepcidin, iron, haemoglobin, and ferritin | Levels of hepcidin and iron were comparable between T2D patients and controls. However, the levels of ferritin and haemoglobin were elevated in patients with T2D. |
| Guo et al., 2013 [26] | China | 1259 participants (555 T2D and 704 controls) | 422 (34%) | T2D (64.45 ± 9.16) [25.3 ± 3.49] Control (58.55 ± 9.56) [24.46 ± 3.33] |
Hepcidin, ferritin and haemoglobin | The levels of hepcidin were comparable between patients with T2D versus controls. However, the levels of ferritin and haemoglobin were elevated in the T2D group. A significant positive correlation was found between hepcidin and haemoglobin levels in patients with T2D. |
| Sam et al., 2013 [29] | Finland | 66 participants (33T2D and 33 controls) | 46 (70%) | T2D (53.34 ± 3.69) [32.23 ± 1.09] Control (49.63 ± 6.50) [31.03 ± 1.82] |
Hepcidin, ferritin, hepcidin: ferritin ratio, haemoglobin | Patients with T2D had lower levels of hepcidin, hepcidin:ferritin ratio and haemoglobin levels when compared to controls. On the other hand, ferritin levels were increased in T2D patients when compared to controls. |
| Andrews et al., 2015 [25] | Chile | 312 participants (166 T2D and 146 controls) | 312 (100%) | T2D# (59.38 ± 9.04) [29.23 ± 3.73] Control (51.4 ± 15.7) [24.6 ± 2.2] |
Hepcidin, iron, ferritin and haemoglobin | Increased levels of hepcidin, iron and ferritin levels were reported in T2D patients in comparison to controls. These increments were further exacerbated by the presence of obesity in T2D patients. Haemoglobin levels were decreased in T2D patients compared to controls. Notably, increased hepcidin levels were associated with iron and increased risk of developing T2D independent of weight. |
| Suarez-Ortegon et al., 2015 [30] | Colombia | 304 participants (65 T2D and 239 controls) | 148 (49%) | T2D (53.1 ± 8.3) [30.4 ± 5.4] Control (45.5 ± 7.7) [26.0 ± 3.6] |
Hepcidin, hepcidin: ferritin ratio, ferritin | Hepcidin levels and hepcidin: ferritin ratio were significantly decreased in patients with T2D in comparison to controls. However, ferritin levels were comparable between T2D and control. |
| Vela et al., 2017 [27] | Not indicated | 80 participants (60 T2D and 20 controls) | 57 (71%) | T2D (55.6 ± 6.1) [28.4 ± 3.7] Control (58.1 ± 9.3) [27.2 ± 3.4] |
Hepcidin, hepcidin: ferritin ratio, ferritin, iron, haemoglobin, haematocrit, and red blood cell count | Hepcidin and hepcidin:ferritin ratios were comparable between T2D patients and control group. However, ferritin and iron levels were increased in T2D patients whilst the levels of haemoglobin, haematocrit and red blood cells count were decreased. There was no significant association between hepcidin levels and glucose or haematological parameters. |
| Altamura et al., 2017 [11] | Germany | 155 Participants (115 T2D and40 Controls) |
113 (73%) | T2D (60.2 ± 6.9) [33.1 ± 5.5] Control (57.9 ± 11.7) [28.0 ± 4.4] |
Hepcidin, iron, ferritin and haemoglobin and haematocrit. | Patients with T2D had reduced hepcidin levels when compared to control group. However, the levels of iron and ferritin were increased in T2D patients whilst haemoglobin and haematocrit levels were comparable. Notably, a significant positive association was found between iron and ferritin levels among patients with T2D. |
| Atyia et al., 2018 [5] | Egypt | 60 participants (40 T2D and 20 controls) | Not reported | T2D (49.23 ± 5.62) [Not reported] Control (48.55 ± 7.76) [Not reported] |
Hepcidin, ferritin, iron and hepcidin: ferritin ratio. | Hepcidin and ferritin levels were elevated in patients with T2D when compared to controls, whilst iron levels were comparable between T2D and control group with T2D patients exhibiting lower hepcidin: ferritin ratio. Elevated iron levels were associated with high risk of T2D. |
| Guo et al., 2018 [7] | China | 44 participants (22 T2D and 22 Controls) | 29 (73%) | T2D (56.45 ± 11.80) [25.48 ± 3.45] Control (52.45 ± 10.01) [24.43 ± 2.33] |
Hepcidin, ferritin and hepcidin: ferritin ratio | Hepcidin and ferritin levels were elevated whilst hepcidin: ferritin ratio was decreased in T2D patients in comparison to the controls. |
| Shalitin et al., 2018 [28] | Israel | 38 participants (18 T2D and 20 controls) | 25 (66%) | T2D (15.1 ± 3.1) [2.45 ± 0.43]∗ Control (13.1 ± 3.0) [2.39 ± 0.36] |
Hepcidin. | There were no differences in hepcidin levels between T2D the control group. |
#
T2D group comprised of lean [Age: 61.3 ± 10.0; BMI: 25.4 ± 2.1] and obese [Age: 58.3 ± 8.3; BMI: 31.4 ± 2.5] groups.
∗
: BMIZ scores.