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. 2022 Feb 17;12:2679. doi: 10.1038/s41598-022-06636-3

Table 1.

Summary of general characteristics of the included studies.

References Country Group Sample size (male/female) Age (year) BMI (kg/m2) Meal test Out-come Sampling time Sample origin Sample procedure Technique
Baranowska62 Poland Control 0/45 26.0 ± 7.6 21.5 ± 0.3 NA AG Fasting Plasma NR RIA
Obese 0/37 41.6 ± 12.4 32.7 ± 0.8
Homaee39 Iran Control 19/0 26.9 ± 1.3 18.5 ± 0.5 NA AG Fasting Plasma EDTA, Aprotinine, HCL ELISA
Obese 19/0 27.5 ± 1.3 31.0 ± 0.8
Iceta75 France Control 0/29 37.0 ± 2.0 21.5 ± 0.4 NA AG, DAG Fasting Plasma Parahydroxymercuribenzoic acid, HCL ELISA
Obese 0/55 38.0 ± 1.5 41.5 ± 0.8
Kołodziejski43 Poland Control 0/15 42.9 ± 5.3 22.3 ± 0.5 NA AG, TG Fasting Serum PMSF, HCL RIA
Obese 0/15 42.2 ± 3.3 39.8 ± 1.0
Nakahara65 Japan Control 0/11 25.7 ± 6.7 21.8 ± 3.1 NA AG, DAG Fasting Plasma EDTA, Aprotinine, HCL ELISA
Obese 0/10 27.7 ± 8.2 28.4 ± 2.7
Ezquerro74 Spain Control 11/19 44.0 ± 2.0 23.1 ± 0.5 NA AG, DAG Fasting Plasma NR ELISA
Obese-NG 16/28 39.0 ± 2.0 46.4 ± 1.3
Obese-IGT 17/25 44.0 ± 2.0 43.2 ± 1.0
Haluzíková69 Czech Republic Control 0/15 44.1 ± 2.8 22.2 ± 0.5 NA AG Fasting Serum DPP-IV inhibitor, Aprotinine MILLIPLEX MAP
Obese 0/17 39.9 ± 2.0 43.2 ± 1.7
Tamboli42 USA Control 0/9 36.0 ± 4.0 22.0 ± 1.0 NA AG, TG Fasting Plasma ETDA, Aprotinine, HCl ELISA
Obese 0/9 41.0 ± 4.0 44.0 ± 2.0
Savage71 USA Control 0/8 44.2 ± 5.5 22.7 ± 1.7 NA AG Fasting Plasma Aprotinine, HCL RIA
Obese 0/19 36.5 ± 1.5 38.6 ± 1.3
Arafat68 Germany Control 6/7 25.1 ± 0.6 21.7 ± 0.6 NA AG, TG Fasting Plasma NR RIA
Obese 5/6 28.4 ± 2.6 34.4 ± 1.7
Rodríguez40 Spain Control 25/30 56.0 ± 2.0 23.1 ± 0.3 NA AG, DAG Fasting Plasma NR ELISA
Obese-NG 41/25 55.0 ± 1.0 32.5 ± 0.5
Obese-IGT 21/16 59.0 ± 1.0 33.5 ± 0.8
Dunn67 USA Control 0/8 40.0 ± 3.2 23.0 ± 0.7 NA AG Fasting Plasma Aprotinine, HCL RIA
Obese 0/14 40.0 ± 2.1 40.0 ± 1.3
Carroll66 USA Control 5/12 NR 22.3 ± 0.5 NA AG Fasting Plasma EDTA, Aprotinine, DPP-IV inhibitor RIA
Obese 12/22 NR 43.4 ± 0.9
Marzullo58 Italy Control 10/10 31.7 ± 1.3 22.4 ± 0.6 NA AG, TG Fasting Plasma EDTA, HCL RIA
Obese 10/10 32.4 ± 1.6 41.3 ± 1.1
Suematsu61 Japan Control 16/1 36.0 ± 1.9 22.2 ± 0.6 NA AG Fasting Plasma NR RIA
Obese 16/1 35.5 ± 1.8 28.7 ± 1.2
Bik63 Poland Control 0/45 26.0 ± 7.6 21.5 ± 0.3 NA AG Fasting Plasma Aprotinine RIA
Obese 0/37 31.6 ± 8.2 32.7 ± 0.8
Marzullo37 Italy Control 8 NR 22.1 ± 1.2 NA AG, TG Fasting Plasma NR RIA
Obese 8 NR 33.7 ± 1.5
Yunker76 USA Control 25 NR NR NA AG Fasting Plasma NR MILLIPLEX MAP
Over weight 24 NR NR
Obese 20 NR NR
Nogueira80 France Control 5/16 33.0 ± 1.3 22.1 ± 0.6 NA DAG Fasting Serum NR ELISA
Obese-low HDL-c 6/15 34.0 ± 2.0 48.4 ± 1.8
Obese-MetS 6/11 38.0 ± 2.7 43.3 ± 1.1
Obese 4/17 37.0 ± 1.1 41.4 ± 0.9
Lopez-Aguilar77 Mexico Control 24/26 26.4 ± 0.8 22.7 ± 0.2 NA AG Fasting Serum Parahydroxymercuribenzoic acid, EDTA, ELISA
Obese 26/54 29.2 ± 0.70 35.4 ± 0.6
Ozkan79 Turkey Low weight 16/15 28.8 ± 2.9 17.6 ± 0.1 NA AG Fasting Serum Aprotinine ELISA
Normal weight 14/14 40.8 ± 3.9 21.7 ± 0.3
Over weight 15/15 52.2 ± 2.3 27.4 ± 0.4
Obese 16/15 52.1 ± 2.8 34.9 ± 0.4
Morbidly obese 15/15 45.8 ± 2.3 44.8 ± 0.8
Gelisgen81 USA Control 7/9 33.0 ± 1.6 23.0 ± 1.7 NA AG Fasting Plasma EDTA, Aprotinine, ELISA
Morbidly obese 9/12 35.2 ± 1.6 49.4 ± 5.3
Karcz-Socha82 Control 22/24 51.2 ± 1.0 23.4 ± 0.2 NA AG, TG Fasting Plasma EDTA, Aprotinine, DPP-IV inhibito, PMSF RIA
Moderately obese 21/22 50.5 ± 0.9 32.5 ± 0.2
Morbidly obese 27/26 52.3 ± 0.9 37.5 ± 0.2
Krzyzanowska-Swiniarska83 Poland Control 0/32 28.8 ± 0.8 21.3 ± 0.3 NA AG Fasting Serum Aprotinine, HCL, PMSF RIA
Obese without insulin resistance 0/30 32.5 ± 1.2 34.4 ± 0.7
Obese with insulin resistance 0/30 32.3 ± 1.2 37.8 ± 1.0
Zwirska-Korczala64 Poland Control 0/8 33.9 ± 3.7 23.2 ± 0.7 Standard mixed breakfast (527 kcal) AG,TG Fasting and postprandial 30, 60, 120 min Plasma EDTA, PMSF, HCL, DPP-IV inhibitor RIA
Moderately obese-MetS 0/12 37.1 ± 2.2 34.9 ± 0.9
Morbidly obese-MetS 0/17 32.3 ± 1.7 46.9 ± 1.6
Rizi44 Singapore Control 9/0 23.2 ± 0.2 22 ± 0.2 High-protein test, high-fat test, high-carbohydrate test (isocaloric 600 kcal) AG Fasting and postprandial 30, 60, 90, 120, 180 min Plasma EDTA, DPP-IV inhibitor, Aprotinine ELISA
Obese 9/0 28.6 ± 1.4 30.1 ± 0.7
Brede73 Germany Control 20/0 24.1 ± 3.7 22.4 ± 1.5 Ad libitum test buffet (1500 kcal) AG,TG Fasting and postprandial 30 minites Plasma Aprotinine RIA
Obese 20/0 25.2 ± 3.7 34.9 ± 3.6
Douglas78 UK Control 10/10 37.5 ± 3.4 22.4 ± 0.3 Standard breakfast (643 kcal for males and 513 kcal for females) AG, DAG Fasting and postprandial 30, 60, 90 min Plasma Aprotinine ELISA
Obese 12/11 45 ± 2.6 29.2 ± 0.6
Seyssel72 Spain Control 20/0 27.0 ± 1.0 22.0 ± 0.3 Standard mixed breakfast (706 kcal) AG Fasting and postprandial 60 minites Plasma Parahydroxymercuribenzoic acid, EDTA, HCl ELISA
Obese 17/0 29.0 ± 2.0 31.9 ± 0.4
Dardzińska41 Poland Control 1/12 37.2 ± 2.6 23.0 ± 1.0 Mixed-meal (300 kcal) AG, DAG Fasting and postprandial 120 minites Plasma EDTA, Parahydroxymercuribenzoic acid ELISA
Obese 7/17 35.4 ± 1.9 43.8 ± 0.7
Heden70 USA Control 14 26 ± 1.6 22.9 ± 0.5 Mixed meal (600 kcal) AG Fasting and postprandial 5, 10, 15, 20, 30, 40, 50, 60, 75, 90, 120, 150, 180, 210, 240 min Plasma EDTA, Aprotinine MILLIPLEX MAP
Obese 14 25.1 ± 1.3 34.8 ± 1.2
Ueda38 Japan Control 7/0 22.4 ± 1.6 22.4 ± 0.9 Standard breakfast (560 kcal) AG Fasting and postprandial 60, 90, 120, 150, 180 min Plasma EDTA, Aprotinine ELISA
Obese 7/0 22.9 ± 1.3 30 ± 1.2
Tentolouris59 Greece Control 0/8 40.2 ± 4.0 21.8 ± 0.8 Carbohydrate-rich meal (546 kcal), fat-rich meal (532 kcal) AG Fasting and postprandial 60, 120, 180 min Plasma NR RIA
Obese 0/8 39.9 ± 5.3 35.51 ± 1.6
Foschi60 Italy Control 3/3 26.2 ± 0.7 22.5 ± 0.7 Liquid test meal (504 kcal) AG Fasting and postprandial 60, 120, 180 min Plasma EDTA RIA
Obese 1/11 41.1 ± 3.8 42.9 ± 1.3

Age and BMI are presented as the means ± SEM; MetS metabolic syndrome, HDL-c high-density lipoprotein-cholesterol, NG normoglycemia, IGT impaired glucose tolerance, AG acyl ghrelin, DAG des-acyl ghrelin, ELISA enzyme-linked immunosorbent assay, RIA radioimmunoassay, MILLIPLEX MAP magnetic bead-based quantitative multiplex immunoassay, EDTA ethylene diamine tetraacetic acid, PMSF phenylmethylsulfonyl fluoride, HCL hydrogen chloride, NA not applicable, NR not reported.