Table 2.
General information of the non-alcoholic fatty liver disease and control groups (n (%)).
| Author, publication year, country | Sample size | NAFLD, n (%) | Non-NAFLD, n (%) | Odds ratio | Confidence interval | Adjusting | Diagnostic methods | Study design |
|---|---|---|---|---|---|---|---|---|
| Hamabe et al., 2011, Japan25 | 1553 | A, R, CC | Abdominal ultrasonography | Retrospective cohort | ||||
| Total smoker | 93 (5.99) | 216 (13.90) | 2.683 | (2.00–3.59) | ||||
| Light | 24 (1.55) | 57 (3.67) | 0.94 | (0.59–1.48) | ||||
| Heavy | 69 (4.44) | 159 (10.24) | 2.7 | (1.95–3.74) | ||||
| Non-smoker | 172 (11.1) | 1072 (69) | ||||||
| Liu et al., 2013, China23 | 2426 | A, I, R, Z, AA, BB, CC, DD, EE, FF | Ultrasonography | Cross-sectional | ||||
| Total smoker | 420 (17.31) | 962 (39.65) | 1.047 | (0.88–F1.25) | ||||
| Light | 162 (6.67) | 421 (17.35) | 0.92 | (1.39–1.30) | ||||
| Heavy | 258 (10.63) | 541 (22.30) | 1.14 | (3.98–7.98) | ||||
| Current | 420 (17.31) | 962 (39.65) | 1.05 | (0.87–1.25) | ||||
| Former | 106 (4.36) | 204 (8.40) | 1.25 | (0.95–1.63) | ||||
| Passive | 5 | 70 | 1.364 | |||||
| Non passive smokers | 4 | 225 | ||||||
| Non-smoker | 294 (12.12) | 705 (29.06) | ||||||
| Zhang et al., 2015, China26 | 800 | A, B, D, E, G, I, L, M, N, O, P, Q, T, U, W, Y | Ultrasonography | Case-control | ||||
| Total smoker | 408 (51) | 55 (6.87) | 5.602 | (3.93–7.98) | ||||
| Light | 171 (21.38) | 31 (3.87) | 4.24 | (2.68–6.46) | ||||
| Heavy | 237 (29.63) | 24 (3.00) | 7.71 | (4.66–11.95) | ||||
| Non-smoker | 192 (24.00) | 145 (18.13) | ||||||
| Chavez-Tapia et al., 2006, Mexico20 | 885 | Not mention | Ultrasonography | Cross-sectional | ||||
| Total smoker | 87 (9.83) | 232 (26.21) | 0.888 | (0.66–1.21) | ||||
| Non-smoker | 168 (18.98) | 398 (44.97) | ||||||
| Caballería et al., 2010, Spain22 | 766 | A, E, G (male), S | Ultrasonography | Cross-sectional | ||||
| Total smoker | 92(12.01) | 250(32.63) | 0.104 | (0.80–1.53) | ||||
| Current | 39(5.09) | 150 (19.58) | 0.78 | (0.40–0.93) | ||||
| Former | 53(6.91) | 100 (13.05) | 1.59 | (0.83–1.87) | ||||
| Non-smoker | 106 (13.83) | 318 (41.51) | ||||||
| Oniki et al., 2013, Japan24 | 696 | A, G, B, EE, DD, R | Ultrasonography | Cross-sectional case-control | ||||
| Total smoker | 61 (8.76) | 221 (31.75) | 1.38 | (0.94–2.02) | ||||
| Current | 21 (3.01) | 57 (8.18) | 1.84 | (0.86–1.18) | ||||
| Former | 40 (5.74) | 164 (23.56) | 1.22 | (0.79–1.87 | ||||
| Non-smoker | 69 (9.91) | 345 (49.56) | ||||||
| Zatu et al., 2014, South Africa41 | 195 | A, G | Not mentioned | Cross-sectional | ||||
| Total smoker | 17 | 44 | 0.629 | (0.33–1.22) | ||||
| Non-smoker | 51 | 83 | ||||||
| Zhang et al., 2015, China34 | 1800 | A, G, HH | Based on guidelines for the diagnosis and treatment of NAFLD revised by the Fatty Liver and Alcoholic Liver Disease Study Group of the Chinese Liver Disease Association in 201042 | Case-control | ||||
| Total smoker | 447 (49.67) | 207 (23) | 3.303 | (2.70–4.05) | ||||
| Light | 144 (16.00) | 116 (12.89) | 1.899 | (1.37–2.55) | ||||
| Heavy | 303 (33.67) | 91 (10.11) | 5.0937 | (3.02–8.35) | ||||
| Non-smoker | 453 (50.33) | 693 (77.00) | ||||||
| Wu et al., 2015, China35 | 587 | H, J, Q, X | Diagnosis of NAFLD was made according to criteria proposed by the fatty liver and alcoholic liver disease study group of the Chinese Liver Disease Association43,44 | Case-control | ||||
| Total smoker | 129 (52.43) | 124 (36.47) | 1.275 | (0.93–1.75) | ||||
| Non-smoker | 177 (49.57) | 217 (63.53) | ||||||
| Koehler et al., 2012, Netherland33 | 2811 | Not mention | Ultrasonography | cross-sectional | ||||
| Total smoker | 660 (23.48) | 1123 (40.00) | 1.266 | (1.08–1.49) | ||||
| Current | 75 (2.67) | 165 (2.31) | ||||||
| Former | 585 (20.81) | 958 (34.08) | ||||||
| Non-smoker | 326 (11.60) | 702 (24.97) | ||||||
| Chang et al., 2013, Korea36 | 43,166 | G, AA, BB, HH | Abdominal ultrasonography | Cohort | ||||
| Smoker | 5133 (44) | 8068 (25.6) | 2.288 | (2.19–2.39) | ||||
| Non-smoker | 6519 (56) | 23,446 (74.4) | ||||||
| Hung et al., 2013, Taiwan37 | 521 | B-mode ultrasonography | Cross-sectional | |||||
| Smoker | 32 (12.3) | 54 (20.8) | 0.533 | (0.33–0.86) | ||||
| Non-smoker | 229 (87.7) | 206 (79.2) | ||||||
| Yang et al., 2012, China38 | 903 | A, B, G | B-mode ultrasonography | Case-control | ||||
| Smoker | 82 (19.2) | 55 (11.8) | 1.735 | (1.20–2.51) | ||||
| Non-smoker | 354 (80.8) | 412 (88.2) | ||||||
| Arslan et al., 2014,Turkey39 | 145 | G, HH | Based on biochemical, radiological, and histological criteria | Cohort | ||||
| Smoker | 29 (29) | 20 (44.4) | 0.511 | (0.25–1.06) | ||||
| Non-smoker | 71 (71) | 25 (55.6) | ||||||
| Koch et al., 2015, Germany30 | 354 | A, G | MRI | Cohort | ||||
| Smoker | 95 (50.8) | 91 (54.5) | 0.862 | (0.57–1.31) | ||||
| Non-smoker | 92 (49.2) | 76 (45.5) | ||||||
| Singh et al., 2015, India32 | 645 | Not mentioned | Ultrasonography and histological confirmation whenever possible | Case–Control | ||||
| Smoker | 49 (10.6) | 12 (6.6) | 1.663 | (0.86–3.20) | ||||
| Non-smoker | 415 (89.4) | 169 (93.4) | ||||||
| Zhang et al., 2014, China31 | 17,920 | Confounding factors | Abdominal ultrasonography | Prospective cohort | ||||
| Smoker | 2178 (66.4) | 11,716 (80) | 0.494 | (0.46–54) | ||||
| Non-smoker | 1101 (33.6) | 2925 (20) | ||||||
| Otgonsuren et al., 2013, United States27 | 10,565 | A, G,L, EE, DD, II | Ultrasonography | Cross-sectional | ||||
| Total smoker | 2241 (89.3) | 7137 (88.6) | 1.072 | (0.93–1.24) | ||||
| Heavy/moderate smoker | 733 (29.2) | 2658 (33) | ||||||
| Light smoker | 1508 (60.1) | 4479 (55.6) | ||||||
| Never smoker | 269 (10.7) | 918 (11.4) | ||||||
| Lin et al., 2014, United States29 | 304 | A | Abdominal ultrasonography | Cross-sectional | ||||
| Smoking exposure | 5 (55.6) | 70 (23.7) | 4.018 | (1.05–15.07) | ||||
| No smoking exposure | 4 (44.4) | 225 (76.3) | ||||||
| Ozturk et al., 2016, Turkey28 | 74 | A, B, C, D, E, F, I, K, L, M, O, P, X, Y, HH, MM,NN, OO | Liver biopsy | Cross-sectional | ||||
| Smoker | 20 (27.03) | 4 (5.40) | 2.353 | (0.69–8.03) | ||||
| Non-smokers | 34 (45.45) | 16 (21.62) |
NAFLD: non-alcoholic fatty liver disease; MRI: magnetic resonance imaging.
A: age; B: body mass index; C: uric acid; D: aspartate transaminase; E: alanine transaminase; F: alkaline phosphatase; G: gender; H: high-density lipoprotein cholesterol; I: fasting serum insulin; J: white blood cell; K: glucose; L: waist circumference; M: hip circumference; N: waist-to-hip ratio; O: systolic blood pressure; P: diastolic blood pressure; Q: fasting blood glucose; R: dyslipidemia; S: metabolic syndrome; T: triglyceride; U: total cholesterol; W: low-density lipoprotein cholesterol; X: homeostatic model assessment (HOMA-IR); Y: high-sensitivity C-reactive protein; Z: education status; AA: alcohol consumption; BB: physical activity; CC: obesity; DD: hypertension; EE: diabetes; FF: use of anti-diabetic medication; HH: smoking status; II: race/ethnicity; MM: ferritin; NN: 2-h oral glucose tolerance test; OO: lipids.