Table 4.
Summary of study topic ordered by the year of publication.
| Manuscript | Sample size | Sample type | Duration |
| Najafi et al (2010) [44] | 38 | 17 diabetic and 21 healthy; gender undefined; and age undefined | Not described |
| Grewal et al (2013) [56] | 39 | 31 diabetic and 8 healthy; gender undefined; and aged 56.9 (SD 8.2) years | Not described |
| Luštrek et al (2014) [36] | 10 | 0 diabetic and 10 healthy; gender undefined; and age undefined | Not described |
| Luštrek et al (2015) [37] | 5 | Health status undefined; 1 female and 4 males; and age undefined | 14 days |
| Cvetković et al (2016) [47] | 9 | 0 diabetic and 9 healthy; 1 female and 8 males; and aged 24-36 years | 14 days |
| Calbimonte et al (2017) [38] | Not described | External data set | Not described |
| Fraiwan et al (2017) [48] | Not described | Healthy; gender undefined; and age undefined | Not described |
| McLean et al (2017) [49] | 22 | 22 diabetic and 0 healthy; gender undefined; and age undefined | Not described |
| Razjouyan et al (2017) [57] | 25 | 25 diabetic and 0 healthy; gender undefined; aged 59.3 (SD 8.3) years | 21 (SD 4) days |
| Reddy et al (2017) [39] | 100 | 50 diabetic and 50 healthy; gender undefined; and aged 34 (SD 10) years (diabetic) and 41 (SD 13) years (healthy) | 5 mnin |
| Turksoy et al (2017) [50] | 26 | 26 diabetic and 0 healthy; 14 females and 12 males; and aged 24.2 (SD 5.41) years | 6 days |
| Bartolic et al (2018) [40] | Not described | Health status undefined; gender undefined; and age undefined | Not described |
| Faccioli et al (2018) [45] | 6 | 6 diabetic and 0 healthy; gender undefined; and age undefined | 5 days |
| Groat et al (2018) [51] | 12 | 12 diabetic and 0 healthy; 8 females and 4 males; and aged 48 (SD 13.4) years | 30 days |
| McMillan et al (2018) [46] | 1 | 1 diabetic and 0 healthy; 0 female and 1 male; and aged 68 years | 1 day |
| Merickel et al (2018) [32] | 36 | 20 diabetic and 16 healthy; gender undefined; and aged 21-59 years | 28 days |
| Nguyen Gia et al (2019) [41] | 4 | 0 diabetic and 4 healthy; gender undefined; aged 30 years | Not described |
| Rescio et al (2019) [33] | 5 | Health status undefined; gender undefined; and aged 47.2 (SD 12.3) years | Not described |
| Sarda et al (2019) [52] | 46 | 46 diabetic and 0 healthy; 17 females and 29 males; and aged 35 (SD 12) years | 140 days |
| Ramazi et al (2019) [34] | 50 | 50 diabetic and 0 healthy; gender undefined; and aged 33-78 years | 7 days |
| Garcia et al (2019) [35] | 100 | 50 diabetic and 50 healthy; 58 females and 42 males; and aged 20-87 years | Not described |
| Sevil et al (2019) [42] | 2 | 2 diabetic and 0 healthy; gender undefined; and age undefined | 1 day |
| Zherebtsov et al (2019) [43] | 55 | 18 diabetic and 37 healthy; gender undefined; and aged 53.2 (SD 11.4) years (diabetic), 19.6 (SD 0.6) years (16 healthy), and 53.2 (SD 11.4) years (21 healthy) | 10 min |
| Rodriguez-Rodriguez et al (2019) [53] | 25 | 25 diabetic and 0 healthy; 11 females and 14 males; and aged 18-56 years | 14 days |
| Sanz et al (2019) [54] | 6 | 6 diabetic and 0 healthy; gender undefined; and aged 36.7 (SD 8.9) years | Not described |
| Whelan et al (2019) [55] | 45 | 0 diabetic and 45 healthy; 27 females and 18 males; and aged 56 (SD 9) years | 42 days |