Table 1.
Characteristics of studies included in the meta–analysis.
| Author | Year | Study design | Location | Cases | Total participants | Follow–up period (years) | Sex | Age at baseline | Tumor site | Exposure | Effect Size (95%CI) Highest vs lowest consumption |
|---|---|---|---|---|---|---|---|---|---|---|---|
| Giovannucci (18) | 1994 | Cohort | USA | 205 | 47,949 | 6 | Male | 40–75 | Colon | Garlic | 0.77 (0.51–1.16) |
| Dorant (19) | 1994 | Case-cohort | Netherlands | 484 | 120,852 | 3.3 | Both | Lung | Onion | 0.80 (0.52–1.24) | |
| Leek | 1.08 (0.80–1.45) | ||||||||||
| Garlic supplements | 1.22 (0.81–1.86) | ||||||||||
| Steinmetz (20) | 1994 | Cohort | USA | 212 | 41,837 | 5 | Female | 55–69 | Colon | Garlic | 0.68 (0.46–1.02) |
| Dorant (21) (1) | 1996 | Case-cohort | Netherlands | 152 | 120,852 | 3.3 | Both | 55–69 | Stomach | Garlic supplements | 1.29 (0.62–2.67) |
| 139 | Stomach | Onion | 0.50 (0.26–0.95) | ||||||||
| Leek | 0.69 (0.42–1.14) | ||||||||||
| Dorant (22) (2) | 1996 | Case-cohort | Netherlands | 443 | 120,852 | 3.3 | Both | 55–69 | Colon | Garlic supplements | 1.36 (0.79–2.35) |
| (293 colon, 150 rectum) | Rectum | 1.28 (0.63–2.60) | |||||||||
| (243 male, 200 female) | Male | Colon | Onion | 0.87 (0.48–1.65) | |||||||
| Rectum | 0.66 (0.28–1.52) | ||||||||||
| Female | Colon | 1.49 (0.79–2.81) | |||||||||
| Rectum | 1.34 (0.55–3.31) | ||||||||||
| Male | Colon | Leek | 1.10 (0.71–1.70) | ||||||||
| Rectum | 0.72 (0.40–1.30) | ||||||||||
| Female | Colon | 1.18 (0.73–1.89) | |||||||||
| Rectum | 1.31 (0.60–2.85) | ||||||||||
| Schuurman (23) | 1998 | Case-cohort | Netherlands | 610 | 58,279 | 6.3 | Male | 55–69 | Prostate | Allium vegetables | 0.95 (0.69–1.33) |
| Onion | 0.93 (0.79–1.10) | ||||||||||
| Leek | 1.38 (1.08–1.76) | ||||||||||
| Li (24) | 2004 | Intervention | China | 142 | 5,033 | 5 | Both | 35–74 | All | Garlic supplements | 0.67 (0.43–1.03) |
| (107 male, 35 female) | (2,526 intervention, 2,507 control) | Stomach | 0.48 (0.21–1.06) | ||||||||
| (53 stomach, 48 liver) | - | Liver | 0.78 (0.35–1.74) | ||||||||
| (63 intervention, 79 control) | Male | All | Garlic supplements | 0.51 (0.30–0.85) | |||||||
| Stomach | 0.36 (0.14–0.92) | ||||||||||
| Liver | 0.71 (0.28–1.78) | ||||||||||
| Female | All | Garlic supplements | 1.50 (0.62–3.61) | ||||||||
| Stomach | 1.14 (0.22–5.76) | ||||||||||
| Liver | 1.17 (0.23–5.92) | ||||||||||
| Schulz (25) | 2005 | Cohort | Europe | 581 | 325,640 | 6.3 (mean) | Female | 19–98 | Ovary | Garlic/onion | 0.79 (0.62–1.01) |
| Lin et al. (26) | 2006 | Cohort | USA | 878 | 107,401 | 10 | Both | 30–75 | Colorectum | Onion | 1.03 (0.82–1.29) |
| 380 | 35,425 | Male | 40–75 | 0.92 (0.65–1.29) | |||||||
| 498 | 71,976 | Female | 30–55 | 1.13 (0.84–1.53) | |||||||
| Boeing (27) | 2006 | Cohort | Europe | 352 | 345,904 | 5.8 | Both | NA | Upper aero-digestive tract | Garlic/onion | 1.17 (0.73–1.86) |
| 255 | 130,633 | Male | 1.04 (0.79–1.36) | ||||||||
| 97 | 215,271 | Female | 1.20 (0.73–1.97) | ||||||||
| Gonzalez (28) | 2006 | Cohort | Europe | 65 | 481,518 | 6.5 | Both | 35–70 | Esophagus | Garlic/onion | 1.27 (0.59–2.73) |
| Larsson (29) | 2006 | Cohort | Sweden | 139 | 82,002 | 7.2 (mean) | Both | Stomach | Allium vegetables | 0.90 (0.58–1.41) | |
| (36,664 female, 45,338 male) | |||||||||||
| Kirsh (30) | 2007 | Cohort | USA | 1,338 | 29,361 | 4.2 (mean) | Male | 55–74 | Prostate | Garlic | 0.88 (0.76–1.03) |
| Onion | 1.01 (0.88–1.17) | ||||||||||
| Satia (31) | 2009 | Cohort | USA | 428 | 77,512 | 5 | Both | 50–76 | Colorectum | Garlic supplements | 1.35 (1.01–1.81) |
| 665 | 77,125 | Lung | Garlic supplements | 1.05 (0.83–1.34) | |||||||
| Epplein (32) | 2010 | Cohort | China | 206 | 73,064 | 12 | Female | 40–70 | Stomach | Allium vegetables | 1.10 (0.74–1.63) |
| 132 | 59,247 | 6 | Male | 40–74 | 0.92 (0.58–1.46) | ||||||
| Walter (33) | 2010 | Cohort | USA | 588 | 66,227 | 6.5 (mean) | Both | 50–76 | Hematologic malignancies | Garlic supplements | 0.55 (0.34–0.87) |
| Gonzalez (34) | 2011 | Cohort | Europe | 1,070 | 299,651 | 9 (mean) | Female | 35–70 | Cervix | Garlic and onions | 1.09 (0.85–1.40) |
| Brasky (35) | 2011 | Cohort | USA | 1,602 | 35,239 | 6.1 (median) | Men | 50–76 | Prostate | Garlic supplements | 1.00 (0.85–1.17) |
| Steevens (36) | 2011 | Case-cohort | Netherlands | 824 | 120,852 | 16.3 | Both | 55–69 | Esophageal squamous cell carcinoma | Allium vegetables | 1.64 (0.88–3.08) |
| Esophageal adenocarcinoma | 0.84 (0.50–1.43) | ||||||||||
| Gastric cardia adenocarcinoma | 1.55 (0.94–2.56) | ||||||||||
| Gastric noncardia adenocarcinoma | 0.97 (0.69–1.35) | ||||||||||
| Esophageal squamous cell carcinoma | Onion | 1.10 (0.79–1.53) | |||||||||
| Eesophageal adenocarcinoma | 0.84 (0.65–1.09) | ||||||||||
| Gastric cardia adenocarcinoma | 1.21 (0.95–1.53) | ||||||||||
| Gastric noncardia adenocarcinoma | 0.91 (0.78–1.06) | ||||||||||
| McCullough (9) | 2012 | Cohort | USA | 1,130 | 99,700 | 7 | Both | 69 | Colorectum | Garlic | 1.03 (0.77–1.37) |
| 579 | 42,824 | Male | 1.19 (0.79–1.79) | ||||||||
| 551 | 56,876 | Female | 0.87 (0.58–1.32) | ||||||||
| 764 | 89,921 | Both | Colorectum | Garlic supplements | 1.03 (0.74–1.44) | ||||||
| 390 | 38,053 | Male | 0.94 (0.57–1.53) | ||||||||
| 374 | 51,868 | Female | 1.09 (0.69–1.72) | ||||||||
| Gonzalez (37) | 2012 | Cohort | Europe | 683 | 477,312 | 11.02 (mean) | Both | 35–70 | Stomach | Garlic/onion | 0.97 (0.76–1.25) |
| Meng (38) | 2013 | Cohort | USA | 1,339 | 76,208 | 24 | Female | 30–55 | Colorectum | Garlic | 1.21 (0.94–1.57) |
| 1,029 | 45,592 | 22 | Male | 40–75 | 1.00 (0.71–1.42) | ||||||
| 578 | 76,208 | 4 | Female | 30–55 | Colorectum | Garlic supplements | 0.72 (0.49–1.07) | ||||
| 559 | 45,592 | 10 | Male | 40–75 | 1.22 (0.83–1.78) | ||||||
| Vogtmann (39) | 2013 | Cohort | China | 398 | 61,274 | 6.3 (median) | Men | 40–74 | Colorectum | Allium | 0.99 (0.77–1.27) |
| Maasland (40) | 2015 | Case-cohort | Netherlands | 415 | 120,852 | 20.3 | Both | 55–69 | Head and neck | Allium | 1.07 (0.76–1.50) |
| Onion | 0.93 (0.77–1.11) | ||||||||||
| Kim (41) | 2018 | Cohort | USA | 292 | 123,484 | Both | Stomach | Garlic | 1.39 (0.89–2.17) | ||
| 138 | 77,086 | 30 | Female | 1.34 (0.72–2.47) | |||||||
| 154 | 46,398 | 28 | Male | 1.45 (0.76–2.78) | |||||||
| Li (10) | 2019 | Intervention | China | 150 | 3365 | 14.7 | Both | 35–64 | Stomach | Garlic supplements | 0.81 (0.57–1.13) |
| (1678 intervention, 1687 control) | |||||||||||
| Yu (42) | 2020 | Cohort | China | 270 | 3199 | 10 | Both | 30–70 | Liver | Garlic | 0.62 (0.42–0.93) |