Table 1.
Characteristics of included studies.
| Study name, year | Country | Age range (mean age) | Sample size | Prevalence of diabetes | RCC cases | LCC cases | Year of baseline data collection | Study duration (years) | Diabetes assessment | Definition type | Adjusted variables |
|---|---|---|---|---|---|---|---|---|---|---|---|
| Nurses’ Health Study (NHS) ( 1 ), 1999 | USA | 30–55 (42.2) | 118,072 | 6% | 275 | 332 | 1976 | 18 | Self-report questionnaire/medical records | 1 a | Age, time periods, BMI, smoking, menopausal status, multivitamin supplement, alcohol, physical activity, aspirin, parental history of CRC and red meat |
| Cohort of Swedish men (COSM) ( 2 ), 2005 | Sweden | 45–79 (N/A) | 45,550 | 6.2% | 98 | 92 | 1997 | 7 | Self-report questionnaire | 1 | Age, BMI, education, family history of CRC, physical activity, smoking, multivitamin supplement, aspirin, consumption of fruits, vegetables, dairy foods and red meat |
| Iowa Women’s Health Study (IWHS) ( 13 ), 2005 | USA | 55–69 (61.5) | 34,972 | 5.4% | 402 | 259 | 1986 | 14 | Self-report questionnaire | 1 | Age, BMI, total energy intake, calcium intake, vitamin E intake |
| Physician’s Health Study (PHS) ( 38 ), 2006 | USA | 40–84 (53.8) | 22,046 | 8.6% | 192 | 151 | 1982 | 21 | Self-report questionnaire | 1 | Age, vigorous exercise, smoking, alcohol, multivitamin use, NSAID use, arthritis, and consumption of fruits and vegetables |
| Cancer Prevention Study II Nutrition Cohort (CPS-II) ( 32 ), 2010 | USA | 50-74 (63.0) | 154,975 | 7.3% | N/A | N/A | 1992-1993 | 15 | Self-report questionnaire /Medical records |
1 | Age, education, body mass index, physical activity, NSAID use, alcohol use, family history of CRC |
| Multiethnic Cohort (MEC) ( 34 ), 2010 | USA | 45–75 (59.9) | 199142 | 15.7% | 1464 | 1091 | 1993-1996 | 13 | Self-report questionnaires | 1 | Age, entry of the cohort, race, BMI, smoking, NSAIDs, education, alcohol, (un-)saturated fat intake, dietary fiber, physical activity and family history of CRC |
| National Institute of Health-AARP Diet and Health Study (NIH-AARP) ( 35 ), 2013 | USA | 50-71 (62.0) | 484,020 | 8.6% | 3,063 | 2,229 | 1995-1996 | 11.2 | Self-report questionnaires | 2 b | Age, race/ethnicity, education, BMI, smoking, physical activity, replacement hormone therapy in women, family history of colon cancer and vitamin and mineral supplements |
| Cohort of Norway (CONOR) ( 36 ), 2015 | Norway | N/A (50.9) | 143,477 | 3.1% | 853 | 606 | 1994-2003 | 15 | Self-report questionnaires | 1 | Age, sex, smoking, alcohol consumption, physical activity, education, family history of cancer, and BMI |
| Netherlands Cohort Study on diet and cancer (NLCS) ( 33 ), 2016 | Netherlands | 55-69 (N/A) | 114,503 | 3.7% | 1,614 | 1,421 | 1986 | 20.3 | Self-report questionnaires | 2 | Age |
| European Prospective Investigation int o Cancer and Nutrition study (EPIC) ( 37 ), 2019 | European countries (Denmark, France, Germany, Greece, Italy, the Netherlands, Norway, Spain, Sweden, and the United Kingdom) | N/A (51.3) | 476,160 | 2.8% | 1,877 | 1,743 | 1992-2000 | 14.9 | Self-report questionnaire | 1 | Age, body mass index, height, physical activity index; smoking status and intensity; education level attained; ever use of menopausal hormone therapy; and intakes of alcohol, red and processed meats, dietary calcium, and fiber |
RR, relative risk; CI, confidence interval; N/A, not available; RCC, right-sided colon cancer; LCC, left-sided colon cancer; BMI, body mass index; CRC, colorectal cancer; NSAIDs, nonsteroidal anti-inflammatory drugs.
a
Definition 1 = splenic flexure included as part of the right colon.
b
Definition 2 = splenic flexure included as part of the left colon.