Summary of results from randomized controlled trials that investigated the prevention of cognitive decline in healthy older adults
| Intervention | No. of patients | Study duration | Overall effect on memory |
|---|---|---|---|
| Cholinesterase inhibitors and NMDA receptor antagonists5–7 | 89 | 3–15 mo | None |
| Hormonal therapies | |||
| Estrogen8–14 | 10 792 | 2 wk–5 yr | Worsened memory |
| Testosterone15–17 | 144 | 3 mo–3 yr | Inconsistent |
| DHEA18–20 | 317 | 6 wk–1 yr | Inconsistent |
| Ginkgo21,22 | 348 | 6 wk–3.5 yr | None |
| Vitamins and fatty acids23–26 | 6 779 | 4 wk–9.6 yr | None |
| Miscellaneous pharmacologic interventions27–30 | 7 530 | 4 wk–3.7 yr | Inconsistent |
| Physical exercise31–33 | 244 | 6 mo–1 yr | Inconsistent |
| Cognitive training34–36 | 3 321 | 3 wk–5 yr | Improvement |
Note: DHEA = dehydroepiandrosterone, NMDA = N-methyl-d-aspartate.