Table 1.
Characteristics of included studies
| Author | Cohort | Year | Location | Age | Study design | Total (n) | Cases (n) | Neoplasia type | Antibiotic | IP/ OP | Level of exposure | Follow-up (years) | Risk estimate (95% CI) |
| Boursi25 | THIN practitioners | 2015 | UK | >40 | Case–control | 103 044 | 20 990 | CRC | Penicillins | OP | >10 courses | 6.5 | 1.20 (1.11 to 1.31) |
| Boursi25 | THIN practitioners | 2015 | UK | >40 | Case–control | 103 044 | 20 990 | CRC | Macrolides | OP | >10 courses | 6.5 | 1.13 (0.94 to 1.36) |
| Boursi25 | THIN practitioners | 2015 | UK | >40 | Case–control | 103 044 | 20 990 | CRC | TMP-SMX | OP | >10 courses | 6.5 | 1.14 (0.94 to 1.38) |
| Boursi25 | THIN practitioners | 2015 | UK | >40 | Case–control | 103 044 | 20 990 | CRC | Cephalosporins | OP | >10 courses | 6.5 | 1.25 (1.02 to 1.52) |
| Boursi25 | THIN practitioners | 2015 | UK | >40 | Case–control | 103 044 | 20 990 | CRC | Tetracyclines | OP | >10 courses | 6.5 | 0.96 (0.79 to 1.18) |
| Boursi25 | THIN practitioners | 2015 | UK | >40 | Case–control | 103 044 | 20 990 | CRC | Quinolones | OP | >10 courses | 6.5 | 0.98 (0.7 to 1.39) |
| Boursi25 | THIN practitioners | 2015 | UK | >40 | Case–control | 103 044 | 20 990 | CRC | Nitroimidazoles | OP | >10 courses | 6.5 | 1.67 (0.65 to 4.33) |
| Kilkkinen26 | Nationwide Finnish Registries | 2008 | Finland | 39–79 | Cohort | 3 112 624 | 7513 | Colon | All antibiotics | OP | ≥6 prescriptions | 7 | 1.15 (1.04 to 1.26) |
| Kilkkinen26 | Nationwide Finnish Registries | 2008 | Finland | 39–79 | Cohort | 3 112 624 | 5126 | Rectal | All antibiotics | OP | ≥6 prescriptions | 7 | 1.03 (0.9 to 1.17) |
| Cao30 | Nurses Health Study | 2018 | USA | 20–39 | Cohort | 16 642 | 1195 | Adenoma | All antibiotics | Both | >2 months | 7 | 1.36 (1.03 to 1.79) |
| Cao30 * | Nurses Health Study | 2018 | USA | 40–59 | Cohort | 16 642 | 1195 | Adenoma | All antibiotics | Both | >2 months | 7 | 1.69 (1.24 to 2.31) |
| Wang | National Health Insurance Claims | 2014 | Taiwan | n/a | Case–control | 640 173 | 3593 | Colon | All antibiotics | Both | Highest tertile | 7.4 | 0.99 (0.81 to 1.2) |
| Wang27 | National Health Insurance Claims | 2014 | Taiwan | n/a | Case–control | 640 173 | 1979 | Rectal | All antibiotics | Both | Highest tertile | 7.4 | 0.93 (0.73 to 1.18) |
| Dik29 | Achema Health Database | 2016 | Netherlands | >18 | Case–control | 20 017 | 4029 | CRC | All antibiotics | n/a | >7 prescriptions | 5 | 1.26 (1.11 to 1.44) |
| Zhang28 | Clinical Practice Research Datalink | 2019 | UK | 40–90 | Case–control | 166 057 | 19 726 | Colon | All antibiotics | n/a | >60 days | 8.1 | 1.17 (1.1 to 1.23) |
| Zhang28 | Clinical Practice Research Datalink | 2019 | UK | 40–90 | Case–control | 166 057 | 9254 | Rectal | All antibiotics | n/a | >60 days | 8.1 | 0.85 (0.79 to 0.93) |
*Estimates for exposure at age 40–59 years were not included in the analysis; exposure at age 20–39 years were used.
CRC, colorectal cancer; IP/OP, inpatient/outpatient; n/a, not available; THIN, The Health Improvement Network; TMP-SMX, trimethoprim-sulfamethoxazole.