Tampubolon Gindo
Cathie Marsh Institute for Social Research, University of Manchester, Manchester, United Kingdom.
PLoS One. 2015 Dec 29;10(12):e0144907. doi: 10.1371/journal.pone.0144907. eCollection 2015.
Dementias in high income countries are set to be the third major burden of disease even as older people are increasingly required to think for themselves how to provide for their lives in retirement. Meanwhile the period of older age continues to extend with increase in life expectancy. This challenge demands an understanding of how cognition changes over an extended period in later life. But studying cognitive ageing in the population faces a difficulty from the fact that older respondents are liable to leave (attrite) before study completion. This study tested three hypotheses: trajectories of cognitive ageing in Britain show an improvement beyond the age of 50; and they are lifted by secular improvement in cognition across cohorts; lastly they are susceptible to distortion due to attrition.
Using the English Longitudinal Study of Ageing, this paper studied trajectories of episodic memory of Britons aged 50-89 from 2002 to 2013 (N = 5931). Using joint models the analysis found that levels of episodic memory follow a curvilinear shape, not a steady decline, in later life. The findings also revealed secular improvement in cognitive ageing such that as a cohort is being replaced episodic memory levels in the population improve. The analysis lastly demonstrated that failure to simultaneously model attrition can produce distorted pictures of cognitive ageing.
Old age in this century is not necessarily a period dominated by cognitive decline. In identifying behavioural factors associated with better cognitive ageing, such as social connections of traditional and online kinds, the paper raises possibilities of mustering an adequate response to the cognition challenge.
在高收入国家，痴呆症将成为第三大主要疾病负担，与此同时，老年人越来越需要自行思考如何为退休生活提供保障。随着预期寿命的增加，老年阶段也在持续延长。这一挑战要求我们了解认知在晚年的较长时期内是如何变化的。但在人群中研究认知老化面临一个困难，即老年受访者在研究完成前容易退出（损耗）。本研究检验了三个假设：英国认知老化的轨迹在50岁之后呈现改善；它们因不同队列认知的长期改善而提升；最后，它们容易因损耗而出现偏差。
利用英国老龄化纵向研究，本文研究了2002年至2013年50 - 89岁英国人的情景记忆轨迹（N = 5931）。通过联合模型分析发现，情景记忆水平在晚年呈曲线形状，而非持续下降。研究结果还揭示了认知老化的长期改善，即随着一个队列被更替，人群中的情景记忆水平有所提高。分析最后表明，未能同时对损耗进行建模会产生认知老化的扭曲图景。
本世纪的老年不一定是由认知衰退主导的时期。在确定与更好的认知老化相关的行为因素时，比如传统和网络形式的社会联系，本文提出了应对认知挑战的充分对策的可能性。
