Introduction
Methods
Evidence acquisition
Inclusion/exclusion eligibility criteria
Screening and data extraction
Quality assessment
Results
Included papers
Study Identifier | Study Design | Sample Size | Population Characteristics | Location & Time Period | Exposure/Independent Variable Tested | Outcome Measures |
---|---|---|---|---|---|---|
1. Azzeh et al. (2022) | Case-control | • N = 423 • Cases = 214 • Controls = 218 | Post-menopausal Arab women with breast cancer | • Saudi Arabia • 2014–2016 | • Dietary consumption of Mediterranean diet • BMI • Smoking status • Caloric intake • Prevalence of cancer | Odds ratio |
2. Bedwani et al. (1997) | Case-control | • N = 308 • Cases = 151 • Controls = 157 | Males with bladder cancer | • Egypt • 1994–1996 | • Smoking status & characteristics | Odds ratio |
3. Khlifi et al. (2013) | Case-control | • N = 520 • Cases = 169 • Controls = 351 | Patients with head and neck cancers | • Tunisia • 2007–2008 | • Occupational exposure (e.g., Chromium and Nickel) | Odds ratio |
4. Nasrollahzadeh et al. (2008) | Case-control | • N = 871 • Cases = 300 • Controls = 571 | Patients with esophageal squamous cell carcinoma | • Iran • 2003–2007 | • Smoking status & characteristics • Other substances intake (e.g., Alcohol) | Odds ratio |
5. Sasco et al. (2002) | Case-control | • N = 353 • Cases = 118 • Controls = 235 | Patients with lung cancer | • Morocco • 1996–1997 | • Smoking status & characteristics • Occupational exposure (e.g., asbestos, iron, nickel, silica, etc…) • History of respiratory disease | Odds ratio |
6. Salarabadi et al. (2015) | Case-control | • N = 152 • Cases = 47 • Controls = 105 | Patients with breast cancer | • Iran • 2012–2014 | • BMI • Occupation • Physical activity • Consumption of calcium and vitamin D • Exposure to sunlight | Odds ratio |
7. Hosseini et al. (2022) | Case-control | • N = 300 • Cases = 150 • Controls = 150 | Patients with breast cancer | • Iran • 2017–2018 | • Dietary intake • BMI • Physical activity • Smoking status • Other substances intake (e.g., Alcohol) • Food quality score (FQS) | Odds ratio |
8. Narmcheshm et al. (2022) | Case-control | • N = 349 • Cases = 178 • Controls = 271 | Patients with gastric cancer | • Iran • 2010–2012 | • Smoking status & characteristics • BMI • Infections (e.g., H.Pylori) • Dietary intake | Odds ratio |
9. Zheng et al. (2012) | Case-control | • N = 4602 • Cases = 1886 • Controls = 2716 | Patients with bladder cancer | • Egypt • 2006–2010 | • Smoking status & characteristics • Infections (e.g., H.Pylori, Schistosomiasis) | Odds ratio |
10. Elkum et al. (2014) | Case-control | • N = 1172 • Cases = 534 • Controls = 638 | Patients with breast cancer | • Saudi Arabia • 2007–2012 | • Dietary intake • BMI • Smoking status & characteristics • Other substances intake (e.g., Alcohol) • Family history of cancer | Odds ratio |
11. Marzbani et al. (2019) | Case-control | • N = 620 • Cases = 212 • Controls = 408 | Females with breast cancer | • Iran • 2013–2015 | • Dietary intake | Odds ratio |
12. Nasher et al. (2014) | Case-control | • N = 180 • Cases = 60 • Controls = 120 | Patients with oral squamous cell carcinoma | • Yemen • 2009–2011 | • Smoking status of “Shamma” • Other substances intake (e.g., Alcohol) • Infections (e.g., Herpes) | Odds ratio |
13. Abdolahinia et al. (2021) | Case-control | • N = 300 • Cases = 100 • Controls = 200 | Patients with bladder cancer | • Iran • 2020 | • Smoking status & characteristics • Other substances intake (e.g., Alcohol, Opium) • Dietary intake • Occupational exposure • Family history of cancer | Odds ratio |
14. Toorang et al. (2021) | Case-control | • N = 224 • Cases = 207 • Controls = 217 | Patients with stomach cancer | • Iran • 2010–2012 | • BMI • Dietary intake | Odds ratio |
15. Fararouei et al. (2019) | Case-control | • N = 1010 • Cases = 505 • Controls = 505 | Female patients with breast cancer | • Iran • 2014–2016 | • BMI • Dietary intake • Physical activity • Smoking status • OCP usage | Odds ratio |
16. Hajjar et al. (2022) | Case-control | • N = 303 • Cases = 103 • Controls = 200 | Patients with breast cancer | • Iran • NA | • Dietary intake • Recommended Food Score (RFS) | Odds ratio |
17. Habibi et al. (2019) | Case-control | • N = 82 • Cases = 41 • Controls = 41 | Patients with viral hepatitis-linked hepatocellular carcinoma (HCC) | • Iran • 2015 | • Aflatoxin B1 levels | Means |
18. Ghiasvand et al. (2012) | Case-control | • N = 986 • Cases = 493 • Controls = 493 | Post-menopausal women with breast cancer | • Iran • NA | • BMI • OCP usage • Duration of breastfeeding • Prevalence of cancer | Odds ratio |
19. Dosemeci et al. (1997) | Case-control | • N = 3207 • Cases = 2378 • Controls = 829 | Male patients with laryngeal or lung cancer | • Turkey • 1979–1984 | • Smoking status & characteristics • Other substances intake (e.g., Alcohol) | Odds ratio |
20. Shivappa et al. (2017) | Case-control | • N = 353 • Cases = 153 • Controls = 202 | Patients with colorectal cancer | • Jordan • 2010–2012 | • Dietary intake (e.g., Dietary Inflammation Index (DII)) | Odds ratio |
21. Simonian et al. (2018) | Case-control | • N = 437 • Cases = 187 • Controls = 250 | Patients with colorectal cancer | • Iran • 2014–2015 | • BMI • Smoking status & characteristics • Occupational history • Physical activity • NSAID usage | Odds ratio |
22. Rafeemanesh Noet al. (2018) | Case-control | • N = 216 • Cases = 104 • Controls = 112 | Patients with breast cancer | • Iran • 2010–2014 | • Physical activity • Occupational history • Smoking status & characteristics | Odds ratio |
23. Ghoreishy et al. (2021) | Case-control | • N = 1050 • Cases = 350 • Controls = 700 | Female patients with breast cancer | • Iran • 2013–2015 | • Dietary intake | Odds ratio |
24. Kaya et al. (2002) | Case-control | • N = 140 • Cases = 70 • Controls = 70 | Patients with non-Hodgkin lymphoma | • Turkey • NA | • Infections (i.e., hepatitis) | Odds ratio |
25. Mazdak et al. (2012) | Case-control | • N = 190 • Cases = 95 • Controls = 95 | Males with prostate cancer | • Iran • 2005–2009 | • Smoking status • Other substances intake (e.g., Alcohol) • Dietary intake • Sexual behavior • Medications history | Odds ratio |
26. Rezaeian et al. (2012) | Case-control | • N = 260 • Cases = 140 • Controls = 120 | Patients with non-Hodgkin lymphoma | • Iran • 2007–2011 | • Infections (i.e., hepatitis) | Odds ratio |
27. Khodavandi et al. (2011) | Case-control | • N = 170 • Cases = 70 • Controls = 100 | Patients with non-Hodgkin lymphoma | • Iran • NA | • Infections (i.e., hepatitis) | Odds ratio |
28. Quadri et al. (2019) | Systematic Review & Meta-Analysis | • Cross-sectional studies (n = 3; pn = 1443) • Case-control (n = 3; pn = 534) | Patients with oral cancer | • Saudi Arabia, Yemen • 1984–2018 | • Smoking status of “Shamma” | Odds ratio |
29. Taha & Eltom (2018) | Literature review | NA | Patients with breast cancer | NA | NA | NA |
30. Tanner & Cheung (2020) | Systematic review | • Case-controls (n = 8; pn = 4939) • None case-controls (n = 5; pn = 2198) | Patients with breast cancer | • Gulf Cooperation Council countries • 2004–2018 | • BMI • Physical activity | Odds ratio |
31. Al-Jaber et al. (2016) | Literature review | N = 9; pn = 3130 | Patients with oral cancer | • Egypt, Iraq, Jordan, Libya, Saudi Arabia, Sudan, Yemen • 1985–2014 | • Smoking status • Dietary intake | Pooled percentages |
32. Alqahtani et al. (2020) | Systematic review | • Cohort (n = 6; pn = 12,964) • Cross-sectional (n = 2; pn = 9180) • Case-control (n = 2; pn = 647) | Patients with oropharyngeal cancer | • Gulf Cooperation Council countries • 1994–2014 | • Smoking status & characteristics | Pooled percentages |
33. Obeid et al. (2020) | Systematic Review & Meta-Analysis | • Set A (n = 39; pn = 6104) • Set B (n = 24; pn = 5114) • Set C (n = 100; pn = 1,272,362) | • A (studies on cervical cancer and HPV prevalence) • B (studies on HPV prevalence and abnormal cervical cytology) • C (HPV prevalence in the general population) | • MENA region • 1999–2019 | • Infections (i.e., HPV) | Pooled prevalence |
34. Etemadi et al. (2017) | Cohort (Prospective) | N = 50,045 | Adult participants of the Golestan Cohort Study | • Iran • 2004–2008 | • Smoking status & characteristics • Other substances intake (e.g., Alcohol) | Odds ratio |
35. Charafeddine et al. (2017) | Cohort (Retrospective) | NA | Patients with cancer | • Lebanon • 2008–2018 | • Smoking status • BMI • Dietary intake • Infections (e.g., H.Pylori) • Other substances intake (e.g., Alcohol) | Estimated population attribution fraction (e-PAF) |
36. Dar et al. (2015) | Cohort (Retrospective) | N = 102 | Patients with oral cancer | • Jordan • 1996–2008 | • Smoking status of “Narghile” | Odds ratio |
37. Wang et al. (2021) | Cohort (Prospective) | N = 48,421 | Adult participants of the Golestan Cohort Study | • Iran | • Alternative Health Eating Index (AHIE) • Health Eating Index (HEI) • Dietary Approach to Stop Hypertension (DASH) • Alternative Mediterranean Diet (AMED) | Hazard ratio |
38. Harfouch et al. (2022) | Cohort (Retrospective) | N = 1117 | Patients with colorectal cancer | • Syria • 2014–2018 | • Physical activity • Occupational history | Raw percentage |
39. Mhawej et al. (2018) | Cohort (Retrospective) | N = 30 | Patients with oropharyngeal squamous cell carcinoma | • Lebanon • 2010–2016 | • Infections (e.g., HPV) • Smoking status • Other substances intake (e.g., Alcohol) | Raw percentage |
40. Abdel-Salam et al. (2020) | Cohort (Retrospective) | N = 229 | Patients with lung cancer | • Qatar • 2010–2014 | • Smoking status | Hazard ratio |
41. Al-Amad et al. (2014) | Cross-sectional | N = 102 | Patients with oral cancer | • Jordan • 1996–2008 | • Smoking status of “Narghile” | Odds ratio |
42. Khodakarami et al. (2012) | Cross-sectional | N = 1651 Cases = 860 Controls = 791 | Participants from the general population and patients with invasive cervical carcinoma | • Iran • 2002–2008 | • Infections (e.g., HPV) | Odds ratio |
Study Identifier | Results | Limitations | Quality score |
---|---|---|---|
1. Azzeh et al. (2022) | • Consuming 1–2 or 3–5 servings of dairy products were protective against breast cancer (OR = 0.178; 95%CI = 0.037–0.859 & OR = 0.038; 95%CI = 0.004–0.372, respectively). • Weekly consumption of 1–2 servings legumes were protective against breast cancer (OR = 0.043; 95%CI = 0.010–0.191). • Consuming 3–5 servings of fruits and vegetables were protective against breast cancer (OR = 0.161; 95%CI = 0.043–0.605). • Consuming 1–2 or 3–5 servings of fish and seafood were protective against breast cancer (OR = 0.211; 95%CI = 0.82–0.545 & OR = 0.072; 95%CI = 0.202–0.265, respectively). • Daily consumption of 1–2 or 3–5 cups of tea were protective against breast cancer (OR = 0.06; 95%CI = 0.010–0.371 & OR = 0.06; 95%CI = 0.009–0.395, respectively). • Daily consumption of 1–2 or more than 5 cups of coffee were protective against breast cancer (OR = 0.159; 95%CI = 0.031–0.812 & OR = 0.144; 95%CI = 0.028–0.736, respectively). | • Questionnaire-related biases (e.g., recall bias) • Limited sample size • Inclusion of postmenopausal women | 8/10 |
2. Bedwani et al. (1997) | • Smoking was associated with a higher likelihood of bladder cancer (OR = 6.6; 95%CI = 3.1–13.9). • Higher duration of smoking was associated with higher risk of bladder cancer (e.g., + 40 years) (OR = 16.5; 95%CI = 6.1–45.2). • Smokers with a history of schistosomiasis were associated with developing bladder cancer (OR = 9.4; 95%CI = 2.9–30.0). | • Type of bladder cancer was not accounted for • Inclusion of only a hospital-based population • Recall bias | 6/10 |
3. Khlifi et al. (2013) | • High blood Chromium was associated with higher risk of developing head and neck cancers (OR = 2.1; 95%CI = 1.3–3.5). • High blood Nickel was associated with higher risk of developing head and neck cancers (OR = 8.87; 95%CI = 5.2–15.2). • Smokers with or without occupational exposure were associated with head and neck cancers (OR = 25.1; 95%CI = 11.8–53.1 & OR = 6.2; 95%CI = 2.9–13.4, respectively). | • Limited sample size | 7/10 |
4. Nasrollahzadeh et al. (2008) | • Using tobacco without concomitant opium was associated with esophageal squamous cell carcinoma (OR = 1.7; 95%CI = 1.1–2.7). • When stratified by drug type, “Nass” was associated with esophageal squamous cell carcinoma (OR = 2.9; 95%CI = 1.5–5.8). • Using more than one type of tobacco products was associated with esophageal squamous cell carcinoma (OR = 1.2; 95%CI = 1.2–3.9). | • Recall bias • Sampling from a single location | 7/10 |
5. Sasco et al. (2002) | • Compared to non-smokers, current light and heavy smokers were associated with higher likelihood of lung cancer (OR = 18.5; 95%CI = 4.1–83.5 & OR = 26.1; 95%CI = 6.6–103.3, respectively). • Users of Hashish/kiff and snuff had a higher likelihood of lung cancer compared to none-users (OR = 6.7; 95%CI = 1.65–29.9). • Passive smoking, occupational exposure, cooking, or kitchen ventilation were not associated with lung cancer. | • Recall bias • Inclusion of only a hospital-based population | 6/10 |
6. Salarabadi et al. (2015) | • Increased body coverage against sunlight (OR = 2.9; 95%CI = 1.2–6.8) and over 5 years of OCP consumption (OR = 3.1; 95%CI = 1.3–7.3) were associated with higher risk of breast cancer among postmenopausal women. • Consumption of solid animal oils (OR = 2.7; 95%CI = 1.4–5.3) and butter or margarine (OR = 1.7; 95%CI = 1.1–2.8) were associated with higher risk of breast cancer. • Reduced consumption of milk (OR = 2.2; 95%CI = 1.1–4.4), yogurt (OR = 4.3; 95%CI = 1.5–11.9), and calcium (OR = 4.9; 95%CI = 1.1–22.3) were associated with higher risk of breast cancer. • Lack of consumption of soya beans (OR = 5.4; 95%CI = 2.5–11.5), green vegetables (OR = 4.1; 95%CI = 1.3–13.3), cabbage (OR = 3.6; 95%CI = 15.4–8.6), carrots (OR = 7.5; 95%CI = 2.9–19.1), and peas (OR = 5.4; 95%CI = 2.5–11.7) were all associated with higher risk of breast cancer. • Weekly consumption of white meat was associated with higher risk of breast cancer (OR = 9.7; 95%CI = 1.1–89.1). | • Recall bias • Limited sample size • Questionable statistics and methodology | 3/10 |
7. Hosseini et al. (2022) | • Participants with high FQS (≥ 28) were less likely to develop breast cancer (OR = 0.58; 95%CI = 0.34–0.97). • When stratified by menopause status, the association persisted for premenopausal women (OR = 0.45; 95%CI = 0.23–0.88) but not their postmenopausal counterparts (OR = 0.76; 95%CI = 0.30–1.93). | • Questionnaire-related biases (e.g., recall bias) • Lack of control for major confounders such as diet | 6/10 |
8. Narmcheshm et al. (2022) | • A diet pattern consisting of pantothenic acid, riboflavin, zinc, animal protein, calcium, biotin, animal fat, vitamin b12, and cholesterol was associated with gastric cancer in men only (OR = 1.86; 95%CI = 1.03–3.34). • A diet pattern consisting of selenium, thiamin, carbohydrates, vegetable protein, vitamin E, vegetable fat, niacin, sodium, and total iron was associated with gastric cancer in men only (OR = 2.15; 95%CI = 1.13–4.09). | • Lack of controls over the age of 70 • Limited sample size | 6/10 |
9. Zheng et al. (2012) | • Among men, history of schistosomiasis is associated with urothelial cell carcinoma (OR = 1.4; 95%CI = 1.2–1.7) and squamous cell carcinoma (OR = 1.4; 95%CI = 1.1–1.7). • Among women, history of schistosomiasis is associated with urothelial cell carcinoma (OR = 1.9; 95%CI = 1.2–2.9) and squamous cell carcinoma (OR = 1.9; 95%CI = 1.2–3.0). • Among men, waterpipe smokers (OR = 1.3; 95%CI = 1.0–1.8), cigarette smokers (OR = 1.8; 95%CI = 1.4–2.2), or smokers of both (OR = 2.9; 95%CI = 2.1–3.9) were associated with urothelial cell carcinoma. However, only dual users were associated with squamous cell carcinoma (OR = 1.8; 95%CI = 1.2–2.6). • For nontobacco men users, environmental tobacco exposure was associated with only urothelial cell carcinoma (OR = 2.5; 95%CI = 1.2–5.1). | • Lack of enough women for statistical analysis • Self-report data for schistosomiasis diagnosis • Recall bias | 6/10 |
10. Elkum et al. (2014) | • Obesity (OR = 2.29; 95%CI = 1.68–3.13), family history of breast cancer (OR = 2.31; 95%CI = 1.60–3.32), usage of HRT (OR = 2.25; 95%CI = 1.65–3.08), and postmenopausal status (OR = 1.72; 95%CI = 1.25–2.38) were associated with higher likelihood of breast cancer. • Breastfeeding (OR = 0.53; 95%CI = 0.34–0.84) and higher educational levels (OR = 0.11; 95%CI = 0.07–0.17) were protective against breast cancer. | • Sampling from a single hospital • Sampling from a hospital-based population • Limited sample size | 5/10 |
11. Marzbani et al. (2019) | • Compared to daily consumption, 2–3 serving per month of vegetables is associated with breast cancer (OR = 2.8; 95%CI = 1.7–4.5). • Consuming soft drinks (OR = 2.8; 95%CI = 1.9–4.3), industrially produced juices (OR = 2.7; 95%CI = 1.1–6.5), fats and oils (OR = 1.9; 95%CI = 1.3–3.0), fried foods (OR = 4.5; 95%CI = 2.1–9.4), and sweets (OR = 2.6; 95%CI = 1.7–3.9) were associated with breast cancer. | • Incomplete assessment of confounders • Questionnaire-related biases (e.g., recall bias) | 5/10 |
12. Nasher et al. (2014) | • Ex- and current “Shammah” use were associated with higher likelihood of OSCC (OR = 12.6; 95%CI = 3.3–48.2 & OR = 39; 95%CI = 14.0–105.0, respectively). • The isolated usage of “Shammah” (OR = 149.5; 95%CI = 12.3–1812.0), in conjunction with “qat” (OR = 43.1; 95%CI = 7.0–266.0), or in conjunction with smoking (OR = 14.2; 95%CI = 2.9–69.0) were all associated with OSCC. • EBV, HPV-18, and HPV-16 were not associated with OSCC. | • Sampling from a single hospital • Sampling from a hospital-based population • Limited sample size • Questionnaire-related biases (e.g., recall bias) | 6/10 |
13. Abdolahinia et al. (2021) | • Light and heavy cigarette smoking were associated with risk of bladder cancer (OR = 3.4; 95%CI = 1.3–8.9 & OR = 15.8; 95%CI = 5.9–42.4, respectively). • Light and heavy consumption of opium were associated with risk of bladder cancer (OR = 6.0; 95%CI = 2.3–15.5 & OR = 11.3; 95%CI = 2.3–15.5, respectively). | • Sampling from a single hospital • Sampling from a hospital-based population • Limited sample size | 4/10 |
14. Toorang et al. (2021) | • Higher consumption of sucrose (OR = 2.94; 95%CI = 1.66–5.19), protein (OR = 2.04; 95%CI = 1.17–3.55), saturated fatty acids (OR = 2.21; 95%CI = 1.26–3.87), monosaturated fatty acids (OR = 1.89; 95%CI = 1.09–3.26), and cholesterol (OR = 2.22; 95%CI = 1.28–3.85) were associated with higher risk of stomach cancer. • While higher percent calories from carbohydrates were protective against stomach cancer (OR = 0.57; 95%CI = 0.33–0.98), higher percent calories from proteins were associated with stomach cancer (OR = 3.09; 95%CI = 1.69–5.61). | • Limited sample size • Questionnaire-related biases (e.g., recall bias) | 5/10 |
15. Fararouei et al. (2019) | • Usage of OCPs (OR = 1.77; 95%CI = 1.32–2.38), smoking (OR = 2.48; 95%CI = 1.56–3.96), and exposure to passive smoking (OR = 1.71; 95%CI = 1.28–2.27) were associated with higher likelihood of breast cancer. • Vigorously intense physical activity was protective against breast cancer (OR = 0.68; 95%CI = 0.47–0.98). • Higher consumption of fruits (OR = 1.84; 95%CI = 1.04–1.28), red meat (OR = 1.15; 95%CI = 1.04–1.28), and fish (OR = 1.55; 95%CI = 1.12–2.76) were associated with higher risk of breast cancer. • Higher consumption of pickles was protective against breast cancer (OR = 0.46; 95%CI = 0.31–0.70). | • Sampling from a single hospital • Sampling from a hospital-based population • Questionnaire-related biases (e.g., recall bias) | 7/10 |
16. Hajjar et al. (2022) | • Higher RFS was protective against breast cancer (OR = 0.31) | • NA | 6/10 |
17. Habibi et al. (2019) | • Serum aflatoxin B1 were significantly higher in patients with HCC than patients with chronic viral hepatitis. | • Limited sample size | 7/10 |
18. Ghiasvand et al. (2012) | • Above normal BMI ranges (25.0–29.9) and (≥ 30.0) were associated higher risk of breast cancer (OR = 1.39; 95%CI = 1.02–1.94 & OR = 1.61; 95%CI = 1.18–2.30, respectively). | • Sampling from a single hospital • Sampling from a hospital-based population • Recall bias | 8/10 |
19. Dosemeci et al. (1997) | • The combined effect of alcohol consumption and cigarette smoking was associated with laryngeal cancer (OR = 12.2; 95%CI = 3.1–57.6). • The combined effect of alcohol consumption and cigarette smoking was associated with lung cancer (OR = 14.1; 95%CI = 3.9–61.2). | • Sampling from a single hospital • Sampling from a hospital-based population • Male patients only | 5/10 |
20. Shivappa et al. (2017) | • Higher DII scores were associated with colorectal cancer (OR = 2.13; 95%CI = 1.23–3.72). | • Sampling from a single hospital • Sampling from a hospital-based population • Limited sample size • Recall bias | 6/10 |
21. Simonian et al. (2018) | • BMI (OR = 1.09; 95%CI = 1.03–1.15) and physical inactivity (OR = 36.09; 95%CI = 10.94–119.0) were associated with higher risk of colorectal cancer. • Consumption of NSAIDs were protective against colorectal cancer (OR = 0.34; 95%CI = 0.19–0.62). | • Sampling from a single hospital • Sampling from a hospital-based population • Limited sample size • Recall bias | 6/10 |
22. Rafeemanesh Noet al. (2018) | • Smoking was associated with increased likelihood of breast cancer (OR = 7.14; 95%CI = 2.63–20.0). | • Sampling from a single hospital • Sampling from a hospital-based population • Limited sample size | 4/10 |
23. Ghoreishy et al. (2021) | • Higher dietary phytochemical index was protective against breast cancer (OR = 0.40; 95%CI = 0.26–0.60). | • Questionnaire-related biases (e.g., recall bias) | 5/10 |
24. Kaya et al. (2002) | • Neither anti hepatitis C levels (OR = 1; 95%CI = 0.61–16.44) or hepatitis G RNA (OR = 5.30; 95%CI = 0.61–48.39) were significantly more present patients with non-Hodgkin lymphoma than their control counterparts. | • Limited sample size • Undisclosed controlling techniques | 5/10 |
25. Mazdak et al. (2012) | • Increased consumption of tomato sauce was protective against prostate cancer risk (OR = 2.5; 95%CI = 1.1–2.9). • Smoking, alcohol consumption, intake of garlic, and intake of fat were not associated with prostate cancer risk. | • Sampling from a single hospital • Sampling from a hospital-based population • Limited sample size • Poor controlling of participant characteristics | 4/10 |
26. Rezaeian et al. (2012) | • Hepatitis G genome levels were not significantly different among patients with non-Hodgkin lymphoma compared to controls (OR = 2.31; 95% = 0.28–35.71). • Patients with non-Hodgkin lymphoma had significantly greater levels of hepatitis C genome levels (OR = 1.16; 95%CI = 1.06–1.28). | • Sampling from a single hospital • Sampling from a hospital-based population • Limited sample size | 5/10 |
27. Khodavandi et al. (2011) | • Hepatitis G genome levels were not significantly different among patients with non-Hodgkin lymphoma compared to controls (OR = 2.92; 95% = 0.26–32.25). • Patients with non-Hodgkin lymphoma had significantly greater levels of hepatitis B genome levels (OR = 6.32; 95%CI = 1.30–30.30). | • Unknown sampling frame • Limited sample size | 4/10 |
28. Quadri et al. (2019) | • Consuming “Shammah” was associated with a higher risk of developing oral cancer (pOR = 38.7; 95%CI = 19.5–76.9). | • Limited sample size • Poor quality of evidence | 6/11 |
29. Taha & Eltom (2018) | • Obesity might be implicated within the development of breast cancer. | • Limited sample size • Poor quality of evidence • Qualitative conclusions | 5/11 |
30. Tanner & Cheung (2020) | • Obesity and physical inactivity are probable risk factors for breast cancer development. | • Limited generalizability • Qualitative conclusions | 4/11 |
31. Al-Jaber et al. (2016) | • Tobacco, both cigarette and smokeless, alcohol drinking, and solar radiation exposure are associated with oral cancer. | • Limited sample size • Poor quality of evidence • Qualitative conclusions | 5/11 |
32. Alqahtani et al. (2020) | • HPV infections and smoking were associated with the development of oropharyngeal cancers. | • Questionable statistics | 5/11 |
33. Obeid et al. (2020) | • HPV prevalence among cervical cancer in the MENA region was 81% (95% CI = 70– 90%). • HPV prevalence among samples with abnormal cervical cytology was 54% (95% CI = 40– 67%). • HPV prevalence among the general population at the MENA region was 16% (95% CI = 14– 17%). | • High heterogeneity • Limited representation of MENA countries | 9/11 |
34. Etemadi et al. (2017) | • Current cigarette smoking is associated with higher cancer-related mortality (HR = 1.75; 95%CI = 1.37–2.25). • Current “nass” smoking is associated with higher cancer-related mortality (HR = 1.40; 95%CI = 1.01–1.95). • Combined current cigarette and “nass” are associated with higher cancer-related mortality (HR = 1.67; 95%CI = 1.02–2.75). • Combined former cigarette and “nass” are associated with higher cancer-related mortality (HR = 1.65; 95%CI = 1.13–2.39). | • Incomplete assessment of confounders • Not accounting for smokers quitting through the prospective follow-up period | 7/11 |
35. Charafeddine et al. (2017) | • Tobacco smoking was related to lung, laryngeal, and bladder cancers for both males and females. • Higher BMI was associated with EGCA, endometrial, and renal cancers for females. It was also associated with EGCA, liver, and colon cancers for males. • Low physical activity was associated with gastroesophageal cancer for both males and females. • Alcohol consumption was associated with oropharyngeal and esophageal cancers for both males and females. • Low adherence to Mediterranean diet and H.pylori infection are associated with gastric cancer for both males and females. • Air pollution was associated with lung cancer for both males and females. | • Dependance on other reports • Lack of confidence intervals | 4/11 |
36. Dar et al. (2015) | • Diagnosis of OSCC at a young age was consistent for both regular narghile smokers and occasional narghile smokers. | • Low level of evidence | 4/11 |
37. Wang et al. (2021) | • Higher tertiles of HEI-2015 (OR = 0.22; 95%CI = 0.08–0.60) were protective of lung cancer in current smokers. • Higher tertiles of DASH-Fung (OR = 0.59; 95%CI = 0.38–0.93) were protective of lung cancer. • Higher tertiles of AMED was associated with higher risk of lung cancer among none-smokers (OR = 3.28; 95%CI = 1.50–7.13). | • Limited sample size • Questionnaire-related biases (e.g., recall bias) | 7/11 |
38. Harfouch et al. (2022) | • Occupational status was associated with colorectal cancer. | • Sampling from a single hospital • Sampling from a hospital-based population | 6/11 |
39. Mhawej et al. (2018) | • Tobacco usage and alcohol usage was associated with oropharyngeal squamous cell carcinoma. | • Limited sample size | 7/11 |
40. Abdel-Salam et al. (2020) | • Smokers have a 291% increased risk of death from lung cancer compared to non-smokers (HR = 3.91; 95% HR = 1.66–9.18). | • Sampling from a single hospital • Sampling from a hospital-based population • Limited sample size • Incomplete assessment of confounders | 6/11 |
41. Al-Amad et al. (2014) | • Regular “Narghile” smoking was associated with lower age at diagnosis for oral cancer. • Occasional “Narghile” smoking was associated with lower age at diagnosis for oral cancer. | • Limited sample size • Questionnaire-related biases (e.g., recall bias) | 5/8 |
42. Khodakarami et al. (2012) | • HPV 16 and 18 accounted for 82.2% (95%: 67.9–92.0) of ICC cases. | • Limited sample size | 7/8 |