Table 2.
Preexisting diabetes and risk of gastric cancer by subgroup meta-analysis using random effect model
| Studies (n) | RR (95%CI) | I2 % (95%CI) | |
| Overall | 27 | 1.19 (1.08-1.31) | 70.7 (56.8-80.2) |
| Countries | |||
| East Asian countries1 | 10 | 1.19 (1.02-1.38) | 60.1 (20.0-80.1) |
| Western countries2 | 17 | 1.18 (1.03-1.36) | 75.6 (61.0-84.8) |
| Study type | |||
| Cohort study | 18 | 1.20 (1.08-1.34) | 75.5 (61.2-84.5) |
| Case control study | 9 | 1.12 (0.87-1.45) | 57.9 (11.8-79.9) |
| Sex | |||
| Male | 12 | 1.10 (0.97-1.24) | 74.9 (55.7-85.8) |
| Female | 9 | 1.24 (1.01-1.52) | 58.9 (14.1-80.3) |
| DM criteria | |||
| Registration | 8 | 1.21 (1.02-1.44) | 83.0 (67.8-91.0) |
| Measured3 | 5 | 1.15 (1.01-1.32) | 35.5 (0.0-75.8) |
| Self report | 14 | 1.13 (0.93-1.39) | 65.2 (38.6-80.3) |
| Interval4 | |||
| One and more years | 15 | 1.15 (1.02-1.31) | 67.5 (44.3-81.0) |
| Quality (NOS) | |||
| High quality (8 and more) | 17 | 1.17 (1.05-1.31) | 73.4 (57.0-83.6) |
| Low quality (7 and less) | 10 | 1.20 (0.97-1.49) | 61.2 (22.6-80.5) |
| Adjustment for risk factor | |||
| Smoking5 | 12 | 1.17 (1.01-1.34) | 52.6 (8.7-75.4) |
| H. pylori5 | 2 | 2.35 (1.24-4.46) | 0.0 (UC) |
| Cancer site | |||
| Cardia cancer | 2 | 1.39 (0.72-2.69) | 82.3 (UC) |
| Noncardia cancer | 2 | 1.19 (0.80-1.77) | 59.6 (UC) |
1
Japan, South Korea;
2
United States, Canada, Europe and Israel;
3
Using fasting blood glucose or HbA1c as criteria;
4
The least cancer-free time of subject according to study design;
5
The subgroup of studies designed to include the risk factor as adjustment variables. RR: Relative risk; UC: Unable to calculate due to low degree of freedom; NOS: Newcastle-Ottawa Quality Assessment Scale; H. pylori: Helicobacter pylori.