Table 1.
Characteristics of included studies.
| Author | Year | Country | Sex(F/M) | Age(year) | BMI (kg/m2) | Leptin source | Assay approach | Study design | |||
|---|---|---|---|---|---|---|---|---|---|---|---|
| Case | Control | Case | Control | Case | Control | ||||||
| Galiniak S | 2022 | Poland | 17/21 | 10/6 | 19.85±7.9 | 19.25±7.3 | 19.89±2.8 | 22.47±2.5 | Serum | ELISA | Cross-sectional study |
| Granados A(NGT) | 2021 | USA | 4/5 | 8/7 | 16±3 | 17±4 | NA | NA | Plasma | RIA | Cross-sectional study |
| Granados A(AGT) | 2021 | USA | 17/20 | 8/7 | 15±3 | 17±4 | NA | NA | Plasma | RIA | Cross-sectional study |
| Granados A(CFRD) | 2021 | USA | 8/5 | 8/7 | 17±3 | 17±4 | NA | NA | Plasma | RIA | Cross-sectional study |
| Polito R | 2019 | Italy | 43/55 | 57/59 | 31.1±7.6 | 30.9±8.7 | 23.4±3 | 22.4±3.6 | Serum | ELISA | Case-control study |
| Nowak JK | 2020 | Poland | 29/27 | 19.09±7.99 | 18.25±3.80 | Serum | ELISA | ||||
| Monajemzadeh M | 2013 | Iran | 20/23 | 17/26 | 3.43±3.16 | 3.87±3.46 | 15.1±0.5 | 21.6±0.6 | Plasma | ELISA | Case-control study |
| Ziai S(NGT) | 2012 | Canada | 20/29 | 10/7 | 27.14±8.05 | 25.28±3.97 | 21.36±2.72 | 22.39±1.69 | Plasma | RIA | Case-control study |
| Ziai S(IGT) | 2012 | Canada | 11/10 | 10/7 | 29.59±9.11 | 25.28±3.97 | 21.61±3.29 | 22.39±1.69 | Plasma | RIA | Case-control study |
| Ziai S(CFRD) | 2012 | Canada | 6/5 | 10/7 | 30.82±8.56 | 25.28±3.97 | 21.36±3.12 | 22.39±1.69 | Plasma | RIA | Case-control study |
| Olveira G | 2012 | Spain | 50/50 | 23/20 | 32.7±4 | 25.1±8.4 | 21.3±3.6 | 22.9±1.8 | Serum | ELISA | Cross-sectional study |
| Speeckaert MM | 2008 | Belgium | 53/63 | 14.95±11.26 | NA | NA | Serum | ELISA | Case-control study | ||
| Cohen RI(mild) | 2008 | USA | 9/10 | 10/10 | 25.36±7.21 | 29.35±2.39 | 23.37±2.6 | 22.64±2.39 | Plasma | ELISA | Case-control study |
| Cohen RI(moderate) | 2008 | USA | 16/14 | 10/10 | 31.64±8.56 | 29.35±2.39 | 22.57±2.88 | 22.64±2.39 | Plasma | ELISA | Case-control study |
| Cohen RI(severe) | 2008 | USA | 10/15 | 10/10 | 36.15±17.29 | 29.35±2.39 | 20.28±4.72 | 22.64±2.39 | Plasma | ELISA | Case-control study |
| Boguszewski MC | 2007 | Brazil | 14/12 | 18/15 | 8.54±2.92 | 8.69±1.83 | NA | NA | Serum | RIA | Cross-sectional study |
| Stylianou C | 2006 | Greece | 7/7 | 10/10 | 19.06±5.08 | 19.05±5.69 | 18.26±2.24 | 22.21±2.77 | Serum | RIA | Case-control study |
| Schmitt-Grohe S(Mild) | 2006 | Germany | 8/14 | 8/14 | 1-43 | 1-40 | 18.94±3.8 | 19.74±2.85 | Serum | ELISA | Case-control study |
| Schmitt-GroheS(Moderate) | 2006 | Germany | 8/14 | 8/14 | 1-43 | 1-40 | 17.14±2.6 | 19.74±2.85 | Serum | ELISA | Case-control study |
| Ahme ML | 2004 | UK | 66/77 | 20/20 | 8.76±11.76 | 9.46±1.15 | NA | NA | Serum | RIA | Case-control study |
| Arumugam R | 1998 | USA | 17/10 | 6/6 | 24.76±5.22 | 25.45±3.57 | 20.71±2.72 | 21.5±2.19 | Serum | RIA | Case-control study |
F, female; M, male; NA, not available; RIA, radioimmunoassay; ELISA, enzyme linked immunosorbent assay; BMI, body mass index; NGT, normal glucose tolerance; AGT, abnormal glucose tolerance; CFRD, cystic fibrosis-related diabetes; IGT, impaired glucose tolerance.