Table 3. Systematic reviews.
| Systematic reviews | ||||||
|---|---|---|---|---|---|---|
| Author, Year | Type of study | Sample | Studies included | Results | Conclusion | LE |
| Batchelor et al. 13 , 2017 | Systematic reviews | 101,616 | One experimental study and 10 observational studies (4 cohort, 1 case-control, 1 cross-sectional, 1 case series, and 3 case reports) | No meta-analysis | Increased risk | II |
| Hussain et al. 17 , 2020 | Systematic review and meta-analysis | 618,911 | 12 observational studies (8 cohort and 4 case-control) | RR=1.05, 95%CI 0.96–1.15 | No association | I |
| Li et al. 12 , 2019 | Systematic review and meta-analysis | 106,599 | 6 cohort studies | RR=1.23; 95%CI 0.90–1.67Follow-up < 5 years: RR=1.62, 95%CI 1.40–1.86 Follow-up > 5years: RR=0.98, 95%CI 0.75–1.27 | No association | I |
| Song et al. 47 , 2019 | Systematic review and meta-analysis | 642,305 | 10 observational studies (5 cohort, 4 case control, and 1 cross-sectional) | ACD: HR=1.04, 95%CI 0.92–1.15 AD: HR 0.96, 95%CI 0.83–1.09 | No association | I |
| Zhang et al. 44 , 2020 | Systematic review and meta-analysis | 166,146 | 6 cohort studies | HR=1.29, 95%CI 1.12–1.49 | Increased risk | I |
| Desai et al. 46 , 2020 | Systematic review and meta-analysis | 308,249 | One experimental study and 5 prospective observational | ACD: HR=1.16, 95%CI 0.86–1.47 | No association | I |
| Khan et al. 45 , 2020 | Systematic review and meta-analysis | 642,949 | 11 observational studies (6 cohort, 4 case control, and 1 cross-sectional) | ACD: HR=1.10; OR=1.03.AD: HR=1.06; OR=0.96 | No association | I |
| Zhang et al. 48 , 2020 | Systematic review and meta-analysis | 371,951 | 10 observational studies | OR=0.87; 95%CI 0.62–1.22 | No association | II |
Abbreviations: RR: relative risk; CI: confidence interval; ACD: all-cause dementia; AD: Alzheimer's dementia; HR: hazard ratio; OR: odds ratio.