Prevalence and Risk of Mild Cognitive Impairment in Low and Middle-Income Countries: A Systematic Review

Article type: Research Article

Authors: McGrattan, Andrea M.^{a; *} | Zhu, Yueping^b | Richardson, Connor D.^a | Mohan, Devi^{c; d} | Soh, Yee Chang^{c; d} | Sajjad, Ayesha^e | van Aller, Carla^a | Chen, Shulin^b | Paddick, Stella-Maria^{f; g} | Prina, Matthew^h | Siervo, Marioⁱ | Robinson, Louise A.^a | Stephan, Blossom C.M.^j

Affiliations: [a] Population Health Sciences Institute, Newcastle University, UK | [b] Department of Psychology and Behavioral Science, Zhejiang University, Hangzhou, China | [c] Global Public Health, Jeffrey Cheah School of Medicine and Health Sciences, Monash University Malaysia, Malaysia | [d] South East Asia Community Observatory (SEACO), Monash University Malaysia, Segamat, Malaysia | [e] Erasmus School of Health Policy and Management; Erasmus University Rotterdam, Rotterdam, The Netherlands | [f] Translational and Clinical Research Institute, Newcastle University, UK | [g] Gateshead NHS Community Health Foundation Trust, Gateshead, UK | [h] Social Epidemiology Research Group, Health Service and Population Research Department, King’s College London, London, UK | [i] School of Life Sciences, The University of Nottingham Medical School, Nottingham, UK | [j] Institute of Mental Health, Division of Psychiatry and Applied Psychology, Nottingham University, UK

Correspondence: [*] Correspondence to: Dr. Andrea McGrattan, Population Health Sciences Institute, Newcastle University, Biomedical Research Building, Campus for Ageing and Vitality, Newcastle upon Tyne, NE4 5PL, UK. Tel.: +44 0 191 208 5467; E-mail: andrea.mcgrattan@newcastle.ac.uk.

Abstract: Background:Mild cognitive impairment (MCI) is a cognitive state associated with increased risk of dementia. Little research on MCI exists from low-and middle-income countries (LMICs), despite high prevalence of dementia in these settings. Objective:This systematic review aimed to review epidemiological reports to determine the prevalence of MCI and its associated risk factors in LMICs. Methods:Medline, Embase, and PsycINFO were searched from inception until November 2019. Eligible articles reported on MCI in population or community-based studies from LMICs and were included as long as MCI was clearly defined. Results:5,568 articles were screened, and 78 retained. In total, n = 23 different LMICs were represented; mostly from China (n = 55 studies). Few studies were from countries defined as lower-middle income (n = 14), low income (n = 4), or from population representative samples (n = 4). There was large heterogeneity in how MCI was diagnosed; with Petersen criteria the most commonly applied (n = 26). Prevalence of amnesic MCI (aMCI) (Petersen criteria) ranged from 0.6%to 22.3%. Similar variability existed across studies using the International Working Group Criteria for aMCI (range 4.5%to 18.3%) and all-MCI (range 6.1%to 30.4%). Risk of MCI was associated with demographic (e.g., age), health (e.g., cardio-metabolic disease), and lifestyle (e.g., social isolation, smoking, diet and physical activity) factors. Conclusion:Outside of China, few MCI studies have been conducted in LMIC settings. There is an urgent need for population representative epidemiological studies to determine MCI prevalence in LMICs. MCI diagnostic methodology also needs to be standardized. This will allow for cross-study comparison and future resource planning.

Keywords: Epidemiology, low-and middle-income country,, mild cognitive impairment, prevalence, risk factors, systematic review

DOI: 10.3233/JAD-201043

Journal: Journal of Alzheimer's Disease, vol. 79, no. 2, pp. 743-762, 2021