Table 1. Characteristics of studies on vegetables and fruit and NPC risk.
| First author, year | Country | Study design | Cases, age | Quality score | RR (95% CI) for highest versus lowest category | Adjustment or matched for |
|---|---|---|---|---|---|---|
| Polesel et al. 2013 | Italy | Case-control (HCC) | 198,Cases: 52Controls: 52 | 8 | 0.51(0.29–0.90) for vegetable0.68(0.40–1.16) for fruit | Age, sex, place of living, year of interview, education, tobacco, smoking, alcohol drinking, and non-alcohol energy |
| Li et al. 2012 | China | Case-control (HCC) | 100,Cases: 48.2Controls: 48.6 | 7 | 0.19(0.05–0.68) for vegetable and fruit combined | Age, sex |
| Shen et al. 2012 | China | Prospective | 1533,46.1 | 7 | 0.78(0.53–1.14) for fruit | Age, BMI, spouse, education, clinical stage, smoking status, alcohol intake |
| Liu et al. 2012 | China | Case-control (HCC) | 600,Cases: 47.39Controls: 47.34 | 7 | 0.37(0.25–0.55) for vegetable and fruit combined0.33(0.22–0.50) for vegetable0.70(0.47–1.04) for fruit | BMI, educational level, marital status, occupation, household income, occupational and domestic exposure to potential toxic substances, chronic rhinitis history, smoking status, passive smoking, daily energy intake (log-transformed), and energy-adjusted intakes of other food groups (including preserved vegetables, cereals, soybeans, fresh meats, preserved meats, roasted meats, dairy products, nuts and vegetables or fruits) by stepwise forward method |
| Turkoz et al. 2011 | Turkey | Case-control (HCC) | 183,Cases: 44.9Controls: 43.9 | 8 | 0.59(0.38–0.94) for fruit | Age and sex |
| Xu et al. 2010 | China | Case-control (HCC) | 184,Cases: 45.9Controls: 47.7 | 7 | 0.30(0.18–0.50) for vegetable and fruit combined0.44(0.27–0.72) for vegetable0.56(0.34–0.92) for fruit | Age, sex, place of living, occupation, educational level, income, smoking status, daily energy intake |
| Jia et al. 2010 | China | Case-control (HCC) | 1387,Cases: 46.92Controls: 47.34 | 6 | 0.63(0.51–0.77) for fruit | Age, sex, education, dialect and household type |
| Luo et al. 2009 | China | Case-control (PCC) | 1256,Cases: 47Controls: 47.23 | 7 | 0.56(0.45–0.70) for fruit | Age, sex, place of living |
| Feng et al. 2007 | Africa | Case-control (HCC) | 636,15–81 | 7 | 0.6(0.4–0.8) for vegetable | Age, sex, socio-economic status variables and exposure to toxic substances |
| Yuan et al. 2000 | China | Case-control (PCC) | 935,15–74 | 8 | 0.85(0.65–1.10) for vegetable | Age, gender, level of education, cigarette smoking, exposure to smoke from heated rapeseed oil and burning coal during cooking, occupational exposure to chemical fumes and history of chronic ear and nose condition (see text for more detailed description of confounding variables) |
| Ward et al. 2000 | China | Case-control (PCC) | 375,≤75 | 7 | 0.9(0.3–2.6) for vegetable0.9(0.3–2.3) for fruit | Age, gender and ethnicity |
| Armstrong et al. 1998 | China | Case-control (PCC) | 282,Cases: 45.29Controls: 44.82 | 7 | 0.50(0.23–1.07) for vegetable | Age, sex, residence and marital status |
| Farrow et al. 1998 | United States | Case-control (PCC) | 133,18–74 | 8 | 0.99(0.51–1.94) for green vegetable0.59(0.29–1.22) for yellow vegetable0.87(0.41–1.83) for fruit | Age, alcohol consumption (0–6, 7–13, 14–20, or 21+ drinks per week), cigarette smoking (never, former, current with history of 1–34 pack years, current with history of 35–59 pack years or current with history of 60+ pack years), total caloric intake, broccoli, cauliflower, spinach, mustard or turnip greens, coleslaw, winter squash, carrots, yams |
| Ning et al. 1990 | China | Case-control (PCC) | 100,Cases: 44.9Controls: 45.2 | 7 | 0.8(0.3–1.9) for vegetable | Age (yr of birth within 5 yr), sex, and race (Han) |
| Yu et al. 1989 | China | Case-control (PCC) | 306,≤50 | 6 | 0.77(0.20–3.33) for vegetable0.3(0.1–1.1) for fruit | Age, sex |
Abbreviations: PCC = population-based case–control study; HCC: hospital-based case–control study; BMI: Body Mass Index.