Details of the cohort studies meeting the inclusion criteria
| Cohort study | Country | Population characteristics (age) | Cohort (% men) | Baseline exposure ascertainment | Outcome | Outcome ascertainment | Follow-up years | Cases (rate/1000) | NOS quality score |
| Inoue et al 36 | Japan | Gen pop (40–69)* | 90 452 (48) | FFQ | HCC | Cancer registry, death records, medical records | 9.7 (average) | 334 (3.7) | 7 |
| Kurozawa et al 35 | Japan | Gen pop (40–79)*; HCC deaths within first 2 years excluded | 110 688 (42) | FFQ | HCC death | Death records | 9–11 (total) | 258 (2.3) | 7 |
| Shimazu et al (cohort 1)39 | Japan | Gen pop (≥40)* | 22 404 (47) | FFQ | PLC | Cancer registry, death records, medical records | 9 (total) | 70 (3.1) | 6 |
| Shimazu et al (cohort 2)39 | Japan | Gen pop (40–64)* | 38 703 (49) | FFQ | PLC | Cancer registry, death records, medical records | 7 (total) | 47 (1.2) | 6 |
| Hu et al 38 | Finland | Gen pop (25–74)* | 60 323 (49) | FFQ | PLC | Cancer registry | 19.3 (median) | 128 (2.1) | 8 |
| Johnson et al 41 | Singapore | Gen pop (45–74)* | 61 321 (44) | FFQ | HCC | Cancer registry and death records | NA | 362 (5.9) | 8 |
| Lai et al 23 | Finland | Male smokers (50–69) from an RCT into lung cancer*; self-reported cirrhosis excluded at baseline | 27 037 (100) | FFQ | LC | Cancer registry | 18.2 (median) | 194 (7.2) | 6 |
| Bamia et al 21 | Europe ** | Gen pop (25–70)* | 486 799 (30) | FFQ | HCC | Cancer registry, death records, health insurance records and mail/telephone | 11 (median) | 201 (0.4) | 7 |
| Setiawan et al 15 | USA | Gen pop (45–75)* | 162 022 (47) | FFQ | HCC | Cancer registry | 18 (median) | 451 (2.8) | 7 |
| Petrick et al 22 | USA | Gen pop (<50–≥70)* | 1 212 893 (41) | FFQ | HCC | Cancer registry, medical records, self-reporting | Variable | 860 (0.7) | 6 |
*Participants with a diagnosis of HCC were excluded at baseline.
**Denmark, France, Germany, Greece, Italy, the Netherlands, Norway, Spain, Sweden, and UK.
FFQ, food frequency questionnaire; HCC, hepatocellular carcinoma; LC, liver cancer; NA, not applicable; NOS, Newcastle-Ottawa Scale; PLC, primary liver cancer; RCT, randomised controlled trial.