Table 1. Characteristics of the studies included in the systematic review and meta-analysis.
| Authors, year | Study characteristics | Identification of CS | Diagnosis of CRC | Outcome (CRC cases: CS/non-CS patients) | Adjustment |
|---|---|---|---|---|---|
| Linos et al., 1981, (19) | Retrospective cohort study (Rochester-Olmsted Epidemiology Program Project): 1681 CS cases (460 males and 1,221 females) at baseline | Medical records | Medical records | 42/– | None |
| Follow-up years: 13 years (mean) | |||||
| Lag period: 6 months | |||||
| Adami et al., 1983, (20) | Prospective population-based cohort study: 16,773 CS patients (5,095 males and 11,678 females) at baseline | ICD code | ICD code | 130/– | None |
| Follow-up period: 11–14 completed years | |||||
| Lag period: none | |||||
| Adami et al., 1987, (21) | Prospective population-based cohort study: 16,439 CS patients (4,978 males and 11,461 females) at baseline | ICD code | ICD code | 150/– | None |
| Follow-up period: 14–17 completed years | |||||
| Lag period: none | |||||
| Nielsen et al., 1991, (22) | Prospective cohort study: 3,425 CS individuals (857 males and 2,568 females) at baseline | Icelandic Cancer Registry | Icelandic Cancer Registry | 57/– | None |
| Follow-up period: 8–33 years | |||||
| Lag period: none | |||||
| Goldbohm et al., 1993, (23) | Prospective cohort study: 3,500 subjects (men: 1,688, 5.7% of gallstones and 4.7% of CS; women: 1,812, 14.7% of gallstones and 13.3% of CS) at baseline | Questionnaire | ICD code | 53/408 | Age and large-bowel cancer in first-degree relatives |
| Follow-up years: 3.3 years (mean) | |||||
| Lag period: none | |||||
| Ekbom et al., 1993, (24) | Retrospective population-based cohort study: 62,615 CS patients (20,745 males and 41,870 females) at baseline | ICD code | ICD code | 633/– | None |
| Follow-up end: until the end of 1987 | |||||
| Lag period: 1 year | |||||
| Johansen et al., 1996, (25) | Retrospective cohort study: 42,098 GSD patients (72.4% with CS) at baseline | ICD code | Danish Classification of Surgical Procedures and Therapies | 344/147 | Age, sex, and calendar year |
| Follow-up years: 1–16 years | |||||
| Lag period: 1 year | |||||
| Lagergren et al., 2001, (26) | Retrospective cohort study: 278,460 CS patients (90,987 males and 187,473 females) at baseline | ICD code | Swedish Classification of Operations and Major Procedures | 3,425/– | None |
| Follow-up years: 12.1 years (mean) | |||||
| Lag period: 1 year | |||||
| Shao et al., 2005, (27) | Retrospective cohort study: 55,960 CS patients and 574,668 randomly selected controls at baseline | General Practice Research Database | General Practice Research Database | 297/2,218 | Age |
| Follow-up end: the first diagnosis of CRC, death, dropout, or the end of database entry (i.e., April 2002) | |||||
| Lag period: 1 year | |||||
| Goldacre et al., 2005, (28) | Retrospective cohort study: 39,254 CS individuals and 334,813 reference controls at baseline | Hospital records | Hospital records | 505/3,731 | None |
| Follow-up end: the date of admission for cancer, or death, or March 31, 1999 | |||||
| Lag period: 2 years | |||||
| Goldacre et al., 2012, (29) | Retrospective cohort study: 327,460 CS individuals, 133,114 gallbladder disease individuals, and 3 million controls at baseline | ICD code | ICD code | 2,245/3,622 | Age in 5-year bands, sex, time period in single calendar years, area deprivation score in quintiles, and region of residence |
| Follow-up end: the date of the first record of colon cancer, death, or the end of the data file (March 31, 2008), whichever was the earliest | |||||
| Lag period: 1 year | |||||
| Chen et al., 2014, (30) | Retrospective cohort study: 5,850 cholelithiasis patients with CS and 62,180 controls at baseline | ICD code | Registry for Catastrophic Illness Patient Database | 67/76 | Sex, age, and comorbidities, such as diabetes mellitus, hyperlipidemia, hepatitis B infection, hepatitis C infection, menopause, and cirrhosis |
| Follow-up years: not mentioned | |||||
| Lag period: none | |||||
| Shabanzadeh et al., 2017, (31) | Retrospective cohort study: 187 CS patients and 5,327 controls at baseline | ICD code | ICD code | 11/183 | Age and sex |
| Follow up years: 24.7 years (mean) | |||||
| Lag period: no | |||||
| Lee et al., 2018, (32) | Retrospective cohort study: 11,362 CS patients and 696,301 non-CS controls at baseline | ICD code | ICD code | 34/4,276 | Sex, diabetes mellitus, and inflammatory bowel disease |
| Follow up years: 13.66 years (mean) | |||||
| Lag period: 1 year | |||||
| Chen et al., 2020, (33) | Retrospective cohort study: 83,963 CS patients and 83,963 control subjects at baseline | ICD code | ICD code | 638/1,170 | Age, gender, comorbidities of hypertension, diabetes mellitus, chronic kidney diseases, stroke, coronary artery disease, colorectal adenomas, and chronic obstructive pulmonary disease |
| Follow-up end: the development of CRC, death, withdrawal from the National Health Insurance program due to emigration or death, or 31 December, 2011 | |||||
| Lag period: 6 months | |||||
| Kim et al., 2020, (34) | Retrospective cohort study: 3,588 CS patients at baseline | Single hospital records | Single hospital records | 21/– | None |
| Follow-up years: 15.0 (range, 0–146) months | |||||
| Lag period: 1 year | |||||
| Jung et al., 2021, (35) | Retrospective cohort study: 408,769 CS patients at baseline | Insurance claims codes | ICD code | 1,773/– | None |
| Follow-up years: 4.7 years (mean) | |||||
| Lag period: 1 year | |||||
| Choi et al., 2022, (36) | Retrospective cohort study: A total of 123,295 control subjects and 123,925 age and sex-matched CS subjects at baseline | Insurance claims codes | ICD code | 1,078/1,003 | Age, sex, smoking status, body mass index, hypertension, diabetes mellitus, and dyslipidemia |
| Follow-up years: 4.59 years (mean) | |||||
| Lag period: 1 year |
CS, cholecystectomy; CRC, colorectal cancer; ICD, International Classification of Diseases; GSD, gallstone disease.