Table 3. Summary risk estimates of the association between exposure to general anesthesia and risk of dementia.
| No. of reports | OR (95% CI) | I2 | P for heterogeneity | |
|---|---|---|---|---|
| Overall | 19 | 1.03 (0.90–1.19) | 83.9% | < 0.001 |
| Subgroup analysis | ||||
| Study design | ||||
| Prospective/cohort | 7 | 1.01 (0.71–1.44) | 88.4% | < 0.001 |
| Case-control | 12 | 1.09 (0.94–1.27) | 78.0% | < 0.001 |
| Study quality | ||||
| High | 16 | 1.14 (0.96–1.36) | 73.2% | < 0.001 |
| Low | 3 | 0.77 (0.53–1.11) | 91.2% | < 0.001 |
| Location | ||||
| America | 9 | 1.02 (0.78–1.34) | 79.8% | < 0.001 |
| Europe | 5 | 1.12 (0.70–1.81) | 72.9% | 0.005 |
| Asia | 3 | 1.14 (0.88–1.47) | 95.1% | < 0.001 |
| Europe-Asia | 1 | 1.20 (0.58–2.48) | - | - |
| International | 1 | 1.00 (0.80–1.30) | - | - |
| Sources of exposure collection | ||||
| Record | 8 | 1.22 (1.01–1.47) | 88.4% | < 0.001 |
| Questionnaire or interview | 8 | 1.01 (0.74–1.38) | 63.3% | 0.008 |
| Type of controls | ||||
| Population-based | 7 | 1.16 (0.91–1.48) | 67.0% | 0.006 |
| Hospital-based | 3 | 1.02 (0.98–1.07) | 0 | 0.924 |
| Number of cases | ||||
| < 250 | 8 | 1.05 (0.75–1.45) | 65.5% | 0.005 |
| ≥ 250 | 8 | 1.00 (0.85–1.17) | 87.9% | < 0.001 |
| Study publication time | ||||
| Earlier than 2010 | 11 | 1.22 (0.91–1.63) | 66.3% | 0.001 |
| 2010– | 8 | 0.94 (0.79–1.12) | 91.4% | < 0.001 |
| Estimate adjusted for age | ||||
| Yes | 16 | 0.99 (0.81–1.19) | 82.9% | < 0.001 |
| No | 3 | 1.50 (0.75–2.98) | 86.4% | 0.001 |
| Estimate adjusted for sex | ||||
| Yes | 12 | 1.03 (0.85–1.25) | 75.1% | < 0.001 |
| No | 6 | 1.21 (0.86–1.70) | 82.8% | < 0.001 |
| Estimate adjusted for education | ||||
| Yes | 3 | 0.77 (0.57–1.04) | 33.9% | 0.22 |
| No | 16 | 1.09 (0.93–1.26) | 84.9% | < 0.001 |