Table 1 . Sociodemographic characteristics and distribution of potential confounding variables in cases and controls .
| Characteristic | Cases | Controls | p |
| Number | 62 | 124 | |
| Sex | |||
| Males (%) | 27(44) | 54(44) | |
| Females (%) | 35(56) | 70(56) | |
| Age (yr) | 37.43 | 36.23 | |
| BMI (kg/m2) | 24.81 | 25.68 | 0.15 |
| Total energy intake (kcal/day) | 2590 | 2902 | 0.00 |
| Education | 0.17 | ||
| Primary(%) | 7(11) | 6(5) | |
| Secondary and high school(%) | 28(45) | 69(55) | |
| University(%) | 27(43) | 49(40) | |
| Family history(%) | 2(3) | 0(0) | 0.11 |
| Smoking(%) | 6(10) | 10(8) | 0.71 |
| h-pylori(%) | 7(11) | 1(0.8) | 0.00 |
| Appendectomy | 4(6) | 0(0) | 0.01 |