Affiliations: [a] Department of Family Medicine, Myongji Hospital, Hanyang University College of Medicine, Goyang, Republic of Korea
| [b] Department of Family Medicine, Yonsei University College of Medicine, Seoul, Republic of Korea
Correspondence:
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Correspondence to: Prof. Jae-Yong Shim, MD, PhD, Department of Family Medicine, Severance Hospital, Yonsei University College of Medicine, 50-1 Yonsei-ro, Seodaemoon-gu, Seoul, 03722, Republic of Korea. Tel.: +82 02 2228 2333; Fax: +82 02 362 2473; E-mail: [email protected].
Abstract: Background:Prevalence of both anemia and cognitive impairment tends to increase with age. Individual studies have recently shown that anemia could be associated with cognitive impairment. Objective:To investigate the association between anemia and cognitive impairment including dementia. Methods:Two of the authors systematically searched PubMed, EMBASE, and the Cochrane library to retrieve observational studies reporting a relationship between anemia and cognitive impairment from 1964 to July 10, 2019. Case-control and cohort studies were included, and odds ratios (ORs) or relative risks (RRs) with 95% confidence intervals (CIs) for the risk of cognitive impairment were calculated using a random-effects model. Results:In total, 16 observational studies including eight case-control studies and eight cohort studies were included in the final analysis. Anemia was significantly linked to cognitive impairment (OR or RR 1.51; 95% CI: 1.32–1.73) in a random-effects meta-analysis, albeit with medium heterogeneity (I2 = 47.8%). Meta-estimates of dementia from prospective population-based cohort studies were similar (RR 1.46; 95% CI: 1.22–1.76) without substantial heterogeneity (I2 = 23.2%). Conclusion:Our meta-analysis indicates that anemia is associated with cognitive impairment. Further prospective research is warranted to determine the cause-effect relationship of anemia with cognitive impairment and whether treatment of anemia might reduce the risk of dementia.
