|Author/Year/Reference||Country and setting||Study design||Number of participants||Exposures and confounders||Outcome||Comparison||Main finding and effects|
|Nashar and Almurshed, 2008 ||Saudi Arabia in King Faisal Specialist Hospital and Research Center (KFSH&RC)||Case-control study||50 cases and 50 controls||Exposures: Dietary intake|
Confounders: Frequency of consumption
|CC||Group I: 50 CRC cases were recruited in the KFSH&RC.|
Group II: 50 controls were selected in the same hospital of cases.
|Lamb meat: OR = 13.5, 95% CI 2.64–68.84|
Chicken with skin: OR = 4, 95% CI 1.53–10.41
Beef meat: OR = 0.18, 95% CI 0.03–0.090
|Bener et al., 2010 ||Qatar in Al-Amal Hospital and Primary Health Care Centers||Case-control study||146 cases and 282 controls matched by age and gender||Exposures: Family history and lifestyle habits|
Confounders: BMI, smoking, family history, soft drinks, bakery products
|CRC||Group I: 146 CRC cases were selected from the registered cases during the period January 2003 to December 2008.|
Group II: 282 controls were identified from the primary heath care centers as healthy with no history of any malignant tumor.
|Frozen meat/chicken: OR = 1.20, 95% CI 0.77–1.87|
|Guesmi et al., 2010 ||Tunis in Charles Nicolle Hospital||Case-control study||32 cases and 61 controls||Exposures: Food group|
Confounders: Age, frequency of consumption (frequently/rarely), milk
|CRC||Group I: 32 CRC cases were selected in the Charles Nicolle hospital.|
Group II: 31 patients with digestive pathology noncancerous were selected in the same hospital of the CRC cases.
Group III: 30 patients with Traumatic pathology noncancerous were recruited from the same hospital of the other groups.
|Delicatessen meat: OR = 5.1, 95% CI 1.4–18.5|
|Arafa et al., 2011 ||Jordan in Al-Bashir Hospital||Case-control study||220 cases and 220 controls matched by age and gender||Exposures: Dietary intake|
Confounders: Vegetables group, fruits, milk , yogurt, tea, bread
|CRC||Group I: 220 CRC cases were recruited in Al-Bashir hospital.|
Group II: 220 controls were selected in the same hospital of cases.
|Red meat: OR = 2.66, 95% CI 1.83–3.88|
Saturated fat: OR = 1.03, 95% CI 1.01–1.05
|Safari et al., 2013 ||Surgical units of the Cancer Institute of Imam Khomeini, Hospital Complex, and three major general hospitals (Shariati, Imam Hussein and Ayatollah Taleghani) in|
Tehran city, Iran
|Case-control study||71 cases and 142 controls matched by age (within 5-year categories) and sex||Exposures: Dietary intake|
Confounders: Family history of CRC in first and second-degree relative, vegetable preparation, aspirin, acetaminophen, mineral and energy intake
|CRC||Group 1: 71 cases with pathologically confirmed CRC, diagnosed no longer than six months before the interview, aged 40–75 years of age at the time of diagnosis and had no previous diagnosis of cancer at other sites, prior history of inflammatory bowel disease or familial adenomatous polyposis.|
Group 2: 142 controls were selected randomly from patients admitted to the same hospitals as cases during the same time period for acute, nonneoplastic conditions and not afflicted with diet-related chronic diseases.
|“Western” dietary pattern (included sugar, processed and red meat, animal butter, refined cereals, tea, pickles, solid oil, mayonnaise, soft drink, legumes, sweets and desserts) increased the risk of CRC by OR = 2.616 (1.361–5.030) p = 0.004|
|Mahfouz et al., 2014 ||Egypt in El-Minia Oncology Centre||Case-control study||150 cases and 300 controls matched by age and sex||Exposures: Dietary intake|
Confounders: Alcohol intake, obesity, smoking, physical activity, alcohol, preserved food
|CRC||Group I: 150 CRC cases were recruited in El-Minia Oncology Centre.|
Group II: 300 controls were selected in the same hospital of cases.
|Red meat: OR = 57.1, 95% CI 12.1–270.3|
|Abu Mweis et al., 2015 ||Jordan in the King Hussein Cancer Center, King Abdullah University, Prince Hamzeh, Jordan University Hospital, and Al-Basheer Hospital||Case-control study||167 cases and 240 controls matched by age, sex, occupation, and marital status||Exposures: Food group|
Confounders: Age, sex, total energy intake, education level, marital status, work income, and family history
|CRC||Group I: 167 CRC cases were recruited from the five major Jordanian hospitals, including an oncology center.|
Group II: 240 controls were selected randomly from among hospital personnel, out patients, visitors, and accompanying individuals.
|Chicken: OR = 2.52, 95% CI 1.33–4.77|
Red meat: OR = 0.64, 95% CI 0.37–1.11
|Tayyem et al., 2015 ||Jordan in the King Hussein Cancer Center, King Abdullah University, Prince Hamzeh, Jordan University Hospital, and Al-Basheer Hospital||Case-control study||169 cases and 248 controls matched by age, sex, occupation, and marital status||Exposures: Macro-micronutrients consumption|
Confounders: Total energy intake, BMI , physical activity, family history, household income, marital status, and tobacco consumption
|CRC||Group I: 169 CRC cases were recruited from five Jordanian hospitals specializing in oncology diagnosis and treatment.|
Group II: 248 controls were recruited from hospital personnel, outpatients, visitors.
|Saturated fat: OR = 5.23 , 95% CI 2.33–11.76|
Cholesterol: OR = 2.48, 95% CI 1.18–5.21
|Azizi et al., 2015 ||Hospitals in Tabriz City of Iran||Case-control study||417 (207 cases and 207 controls) matched by age and sex (within 10-year categories)||Exposures: Dietary intake|
Confounders: History of diabetes, family history of CRC in first-degree relative, physical activity, BMI
|CRC||Group 1: 207 cases with CRC (confirmed by pathology and colonoscopy findings, diagnosed no longer than 6 months before the interview).|
Group 2: 207 controls free of neoplastic conditions and diet-related chronic diseases (from the same hospital at the same period as the cases selected).
Inclusion criteria were age 35–75 years old, CRC confirmed for the cases, being free of CRC for the controls and informed consent.
|Significant association was observed between Iranian dietary pattern (included fried chicken, processed and red meat, black tea, carbonated beverage) and colorectal cancer after adjusting for history of CRC in first-degree relative, history of diabetes, and physical activity: OR = 1.46 (1.05–2.19), p = 0.021|
|Tayyem et al., 2016 ||Five large Jordanian hospitals with oncology services.||Case-control study||220 cases and 281 controls matched by age, sex, occupation, and marital status||Exposures: Meat, dairy products and fats|
Confounders: Age, sex, BMI, physical activity level, total energy intake, income, occupation, education level, marital status, cigarette smoking (current or lifelong; ever or never), other health problems and family history of CRC
|CRC||Group I: 220 were diagnosed CRC cases were recruited conveniently from five large Jordanian hospitals with oncology services.|
Group II: 281 controls were recruited from hospital personnel, outpatients and visitors.
|Chicken (OR = 15.32, 95% CI = 3.28–71.45, Ptrend = 0.009) and Mortadella, a type of processed meat (OR = 9.08, 95% CI = 1.02–80.58, Ptrend = 0.049)|
Steak: 0.42 (0.14–1.24)
Liver: 2.88 (0.25–32.81)
|El-Moselhy et al., 2017 ||General Surgery, Tropical Medicine, and Internal Medicine Clinics, Al-Azhar University Hospitals, Assiut and Cairo||Case-control study||160 cases and 300 controls||Exposures: Lifestyle, and socio-demographic and dietary data|
Confounders: BMI, physical activity
|CRC||Group I: 160 patients with CRC attending the General Surgery, Tropical Medicine, and Internal Medicine Clinics, Al-Azhar University Hospitals, Assiut and Cairo.|
Group II: 300 healthy subjects (relatives to other patients attending these clinics and free from any type of cancer).
|Processed meats intake (OR = 5.12, 95% CI 3.08–8.53)|
Low white meats intake (OR = 2.17, 95% CI 1.4–3.37)
High animal fat intake (OR = 5.59, 95% CI 3.52–8.9)