BACKGROUND Mild cognitive impairment (MCI) is the preclinical and transitional stage between healthy ageing and dementia that may be a potential 'target' for interventions designed to delay progression to dementia. In this systematic review and meta-analysis, we assessed the prevalence of MCI worldwide in community-dwelling adults aged 50 years and older. METHODS PubMed, Web of Science, Embase and PsycINFO database searches were conducted from their respective inception dates to 1 September 2021. Data on the overall prevalence of MCI were synthesised using random effects models. RESULTS A total of 66 articles covering 242,804 participants fulfilled study criteria for inclusion. The overall prevalence of MCI was 15.56% (95%CI: 13.24-18.03%). Prevalence rates of amnestic MCI and non-amnestic MCI were 10.03% (95%CI: 7.98-12.27%) and 8.72% (95%CI: 6.78-10.89%), respectively. The prevalence of MCI increased with age and decreased with education level. Subgroup and meta-regression analyses revealed that region of study site and male gender proportion per sample were significant correlates of MCI prevalence. CONCLUSION The global prevalence of MCI among community dwellers is over 15% and is affected by age, gender, education level and region of study sites. Assessment and interventions targeting MCI within at-risk population subgroups should be considered toward the prevention of dementia.

中文翻译：

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50 岁及以上社区居民轻度认知障碍的全球患病率：流行病学研究的荟萃分析和系统评价。

背景 轻度认知障碍 (MCI) 是健康老龄化和痴呆之间的临床前和过渡阶段，可能是旨在延缓痴呆进展的干预措施的潜在“目标”。在这项系统回顾和荟萃分析中，我们评估了全世界 50 岁及以上社区居民中 MCI 的患病率。方法 PubMed、Web of Science、Embase 和 PsycINFO 数据库搜索从各自的开始日期到 2021 年 9 月 1 日进行。使用随机效应模型合成了 MCI 总体流行率的数据。结果 共有 66 篇文章，涵盖 242,804 名参与者，符合纳入研究标准。MCI 的总体患病率为 15.56%（95%CI：13.24-18.03%）。遗忘性 MCI 和非遗忘性 MCI 的患病率分别为 10.03% (95%CI: 7.98-12.27%) 和 8. 分别为 72%（95%CI：6.78-10.89%）。MCI 的患病率随着年龄的增长而增加，随着教育水平的增加而降低。亚组和元回归分析显示，研究地点的区域和每个样本的男性性别比例与 MCI 患病率显着相关。结论 MCI 在社区居民中的全球患病率超过 15%，并受年龄、性别、教育水平和研究地点区域的影响。应考虑针对高危人群亚群中的 MCI 进行评估和干预，以预防痴呆症。结论 MCI 在社区居民中的全球患病率超过 15%，并受年龄、性别、教育水平和研究地点区域的影响。应考虑针对高危人群亚群中的 MCI 进行评估和干预，以预防痴呆症。结论 MCI 在社区居民中的全球患病率超过 15%，并受年龄、性别、教育水平和研究地点区域的影响。应考虑针对高危人群亚群中的 MCI 进行评估和干预，以预防痴呆症。