Muniz-Terrera Graciela, Matthews Fiona, Dening Tom, Huppert Felicia A, Brayne Carol
MRC Biostatistics Unit, Institute of Public Health, Robinson Way, University Forvie Site, Cambridge, CB2 0SR, UK.
Age Ageing. 2009 May;38(3):277-82. doi: 10.1093/ageing/afp004. Epub 2009 Feb 28.
the investigation of cognitive decline in the older population has been hampered by analytical considerations. Most studies of older people over prolonged periods suffer from loss to follow-up, yet this has seldom been investigated fully to date. Such considerations limit our understanding of how basic variables such as education can affect cognitive trajectories.
we examined cognitive trajectories in a population-based cohort study in Cambridge, UK, of people aged 75 and over in whom multiple interviews were conducted over time. Cognitive function was assessed using the Mini-Mental State Examination (MMSE). Socio-demographic variables were measured, including educational level and social class. An age-based quadratic latent growth model was fitted to cognitive scores. The effect of socio-demographic variables was examined on all latent variables and the probability of death and dropout.
at baseline, age, education, social class and mobility were associated with cognitive performance. Education and social class were not related to decline or its rate of change. In contrast, poor mobility was associated with lower cognitive performance, increased cognitive decline and increased rate of change of cognitive decline. Gender, age, mobility and cognitive ability predicted death and dropout
contrary to much of the current literature, education was not related to rate of cognitive decline or change in this rate as measured by MMSE. Higher levels of education do not appear to protect against cognitive decline, though if the MMSE is used in the diagnostic process, individuals with less education may be diagnosed as having dementia somewhat earlier.
对老年人群认知能力下降的研究受到分析因素的阻碍。大多数针对老年人的长期研究都存在失访问题，但迄今为止对此很少进行充分调查。这些因素限制了我们对教育等基本变量如何影响认知轨迹的理解。
我们在英国剑桥进行了一项基于人群的队列研究，对75岁及以上的人群进行了多次随访访谈，以研究认知轨迹。使用简易精神状态检查表（MMSE）评估认知功能。测量了社会人口统计学变量，包括教育水平和社会阶层。对认知分数拟合了基于年龄的二次潜在增长模型。研究了社会人口统计学变量对所有潜在变量以及死亡和失访概率的影响。
在基线时，年龄、教育、社会阶层和行动能力与认知表现相关。教育和社会阶层与认知能力下降或其变化率无关。相比之下，行动能力差与较低的认知表现、认知能力下降加剧以及认知能力下降变化率增加有关。性别、年龄、行动能力和认知能力可预测死亡和失访情况。
与当前许多文献相反，在本研究中，教育与认知能力下降率或通过MMSE测量的该下降率的变化无关。较高的教育水平似乎并不能预防认知能力下降，不过如果在诊断过程中使用MMSE，受教育程度较低的个体可能会更早被诊断为患有痴呆症。
