Table 1.
Subgroup analysis of relative risks for the association between tooth loss and both dementia and cognitive decline.
| Subgroup | No of studies | Relative risk | 95%CI | Heterogeneity | |||
|---|---|---|---|---|---|---|---|
| Q | P | I2 (%) | |||||
| Subgroup analysis of dementia | |||||||
| Overall | 1.15 | 1.10–1.20 | 117 | <0.01 | 67.4 | ||
| Geographic location | Asia | 7 | 1.15 | 1.10–1.21 | 132 | <0.01 | 79.6 |
| Europe | 3 | 1.06 | 0.81–1.38 | 10 | 0.11 | 42.3 | |
| North America | 3 | 1.01 | 0.92–1.12 | 9 | 0.57 | 0.0 | |
| Mixed | 1 | 1.35 | 1.14–1.60 | 2 | 0.16 | 50.2 | |
| Sex | Male | 3 | 1.19 | 1.09–1.30 | 2 | 0.89 | 0.0 |
| Female | 5 | 1.14 | 1.01–1.29 | 17 | 0.049 | 47.0 | |
| Mixed | 9 | 1.16 | 1.10–1.22 | 101 | <0.01 | 74.2 | |
| Denture use | No | 2 | 1.70 | 1.19–2.41 | 0 | 0.71 | 0.0 |
| Yes | 3 | 1.04 | 0.89–1.21 | 1 | 0.87 | 0.0 | |
| Mixed | 12 | 1.15 | 1.09–1.20 | 110 | <0.01 | 70.8 | |
| Edentulousness | No | 9 | 1.12 | 1.06–1.18 | 81 | <0.01 | 72.9 |
| Yes | 6 | 1.15 | 1.10–1.20 | 11 | 0.13 | 37.8 | |
| Mixed | 7 | 1.21 | 1.07–1.36 | 20 | 0.01 | 59.3 | |
| Number of teeth | 0–9 | 9 | 1.22 | 1.11–1.33 | 36 | <0.01 | 63.7 |
| 10–19 | 3 | 1.04 | 0.95–1.13 | 9 | 0.06 | 56.0 | |
| ≥20 | 2 | 1.16 | 1.13–1.20 | 0 | 0.53 | 0.0 | |
| Mixed | 9 | 1.12 | 1.02–1.22 | 35 | <0.01 | 59.4 | |
| Unspecific | 2 | 1.17 | 1.06–1.28 | 2 | 0.34 | 6.3 | |
| Tooth loss assessment | By a dentist | 9 | 1.16 | 1.10–1.22 | 93 | <0.01 | 74.1 |
| Self-report | 5 | 1.12 | 1.02–1.22 | 23 | 0.04 | 43.1 | |
| Follow-up duration | ≥5 years | 11 | 1.18 | 1.12–1.24 | 57 | <0.01 | 52.7 |
| < 5 years | 2 | 1.24 | 1.01–1.51 | 5 | 0.32 | 15.5 | |
| Mixed | 1 | 1.08 | 1.00–1.17 | 34 | <0.01 | 85.2 | |
| Type | AD | 6 | 1.12 | 1.02–1.23 | 15 | 0.053 | 47.9 |
| VaD | 3 | 1.25 | 1.06–1.47 | 18 | <0.01 | 71.5 | |
| Mixed | 13 | 1.17 | 1.10–1.23 | 93 | <0.01 | 64.5 | |
| Subgroup analysis of cognitive decline | |||||||
| Overall | 1.20 | 1.14–1.26 | 26 | 0.04 | 42.3 | ||
| Geographic location | Asia | 3 | 1.26 | 1.04–1.53 | 29 | 0.18 | 45.2 |
| Europe | 1 | 1.08 | 0.93–1.27 | 0 | 0.82 | 0.0 | |
| North America | 3 | 1.12 | 1.05–1.19 | 1 | 0.88 | 0.0 | |
| Mixed | 1 | 1.30 | 1.15–1.46 | 2 | 0.18 | 45.2 | |
| Sex | Male | 1 | 1.10 | 1.01–1.18 | 0 | 0.84 | 0.0 |
| Mixed | 7 | 1.22 | 1.16–1.29 | 20 | 0.10 | 34.4 | |
| Denture use | No | 2 | 1.26 | 1.18–1.34 | 5 | 0.30 | 18.4 |
| Yes | 2 | 1.02 | 0.85–1.22 | 16 | <0.01 | 74.9 | |
| Mixed | 6 | 1.17 | 1.09–1.25 | 14 | 0.08 | 42.9 | |
| Edentulousness | No | 2 | 1.20 | 1.13–1.28 | 5 | 0.31 | 16.2 |
| Yes | 3 | 1.27 | 1.14–1.41 | 8 | 0.18 | 37.3 | |
| Mixed | 4 | 1.12 | 1.05–1.20 | 4 | 0.38 | 5.4 | |
| Tooth number | 0–9 | 5 | 1.20 | 1.00–1.44 | 32 | <0.01 | 78.4 |
| 10–19 | 1 | 1.23 | 1.13–1.33 | 0 | – | – | |
| Mixed | 3 | 1.23 | 1.12–1.35 | 3 | 0.39 | 0.2 | |
| Unspecific | 2 | 1.11 | 1.04–1.18 | 0 | 0.86 | 0.0 | |
| Tooth loss assessment | By a dentist | 4 | 1.16 | 1.04–1.31 | 11 | 0.15 | 35.3 |
| Self-report | 4 | 1.17 | 1.07–1.29 | 27 | <0.01 | 74.4 | |
| Follow-up duration | ≥5 years | 6 | 1.18 | 1.09–1.27 | 38 | <0.01 | 66.0 |
| < 5 years | 2 | 1.67 | 0.61–4.53 | 3 | 0.07 | 70.5 | |