Mendis Sahan Benedict, Raymont Vanessa, Tabet Naji
South London and Maudsley NHS Foundation Trust, London, United Kingdom.
Oxford Brain Health Clinical Trials Unit, Oxford, United Kingdom.
Front Neurol. 2021 Apr 15;12:628368. doi: 10.3389/fneur.2021.628368. eCollection 2021.
Dementia is a global public health priority which cost global societies $818 billion in 2015 and is disproportionately impacting low and middle-income countries (LMICs). With limited availability of disease modifying drugs to treat Alzheimer's disease (AD), researchers have increasingly focused on preventative strategies which may promote healthy cognitive aging and mitigate the risk of cognitive impairment in aging. Lifelong bilingualism has been presented as both a highly debated and promising cognitive reserve factor which has been associated with better cognitive outcomes in aging. A recent metanalysis has suggested that bilingual individuals present on average 4.05 years later with the clinical features of AD than monolinguals. Bilinguals are also diagnosed with AD ~2.0 years later than monolingual counterparts. In this perspective piece we critically evaluate the findings of this metanalysis and consider the specific implications of these findings to LMICs. Furthermore, we appraise the major epidemiological studies conducted globally on bilingualism and the onset of dementia. We consider how both impactful and robust studies of bilingualism and cognition in older age may be conducted in LMICs. Given the limited expenditure and resources available in LMICs and minimal successes of clinical trials of disease modifying drugs we propose that bilingualism should be positioned as an important and specific public health strategy for maintaining healthy cognitive aging in LMICs. Finally, we reflect upon the scope of implementing bilingualism within the education systems of LMICs and the promotion of bilingualism as a healthy cognitive aging initiative within government policy.
痴呆症是全球公共卫生的重点问题，2015年给全球社会造成了8180亿美元的损失，且对低收入和中等收入国家（LMICs）的影响尤为严重。由于治疗阿尔茨海默病（AD）的疾病修饰药物供应有限，研究人员越来越关注预防策略，这些策略可能促进健康的认知老化，并降低衰老过程中认知障碍的风险。终身双语被认为是一个备受争议但很有前景的认知储备因素，与老年人更好的认知结果相关。最近的一项荟萃分析表明，双语者出现AD临床特征的时间平均比单语者晚4.05年。双语者被诊断出患有AD的时间也比单语者晚约2.0年。在这篇观点文章中，我们批判性地评估了这项荟萃分析的结果，并考虑了这些结果对低收入和中等收入国家的具体影响。此外，我们评估了全球范围内关于双语与痴呆症发病的主要流行病学研究。我们思考如何在低收入和中等收入国家开展对老年人双语与认知的既有影响力又稳健的研究。鉴于低收入和中等收入国家可用的支出和资源有限，以及疾病修饰药物临床试验取得的成功有限，我们建议将双语定位为低收入和中等收入国家维持健康认知老化的一项重要且具体的公共卫生策略。最后，我们思考在低收入和中等收入国家的教育系统中实施双语的范围，以及将双语作为政府政策中促进健康认知老化倡议的推广情况。
