Table 1.
Summary of results from five meta-analyses examining brain injury and neurologic outcomes
| Meta-analysis | # of studies* | Pooled results | |
|---|---|---|---|
| Mortimer et al. [45] | 8 | RR for head trauma and AD | 1.82 (1.26–2.67) |
| 8 | • Among men | 2.67 (1.64–4.41) | |
| 7 | • Among women | 0.85 (0.43–1.70) | |
| 5 | • TBI ≤10 years before dementia onset | 5.33 (1.55–18.3) | |
| 5 | • TBI >10 years before dementia onset | 1.63 (1.04–2.57) | |
| 5 | • Age of AD onset <70 years | 1.95 (1.12–3.48) | |
| 5 | • Age of AD onset 70+ years | 1.81 (1.03–3.25) | |
| Launer et al. [46] | 4 | RR for head trauma and dementia | 1.14 (0.74–1.56) |
| 4 | RR for head trauma and AD | 1.02 (0.68–1.51) | |
| 4 | • Among men | 1.66 (0.94–2.95) | |
| Fleminger et al. [47] | 15 | OR for head injury and AD | 1.58 (1.21–2.06) |
| 8 | • Among men | 2.29 (1.47–3.58) | |
| 7 | • Among women | 0.91 (0.56–1.47) | |
| 7 | • Studies conducted after 1991 | 1.35 (0.94–1.94) | |
| Perry et al. [48] | 7 | OR for TBI and dementia | 1.36 (0.84–2.19) |
| 19 | OR for TBI and AD | 1.40 (1.02–1.90) | |
| 15 | OR for TBI and PD | 1.45 (1.18–1.78) | |
| 2 | OR for TBI and MCI | 2.69 (1.51–4.77) | |
| Li et al. [49] | 11 | RR for head injury and dementia | 1.63 (1.34–1.99) |
| 5 | • Among men | 1.81 (1.38–2.38) | |
| 1 | • Among women | 1.30 (0.60–2.81) | |
| 28 | RR for head injury and AD | 1.51 (1.26–1.80) | |
| 11 | • Among men | 1.70 (1.35–2.13) | |
| 5 | • Among women | 1.17 (0.89–1.53) | |
| 2 | RR for head injury with LOC and dementia | 0.92 (0.67–1.27) | |
| 8 | RR for head injury with LOC and AD | 1.49 (0.91–2.43) |
AD, Alzheimer’s disease; LOC, loss of consciousness; MCI, mild cognitive impairment; OR, odds ratios; PD, Parkinson’s disease; RR, relative risk; TBI, traumatic brain injury. NOTE: Bolding identifies significant results.
*
Length of follow-up ranged from 0 to 43 years across all studies.