Newcastle University Institute for Ageing and Institute for Health and Society, Newcastle University, Newcastle Biomedical Research Building, Newcastle upon Tyne, NE4 5PL, UK.
Division of Psychiatry and Applied Psychology, Institute of Mental Health, School of Medicine, University of Nottingham, Innovation Park, Nottingham, NG7 2TU, UK.
Eur J Epidemiol. 2019 Nov;34(11):1085-1092. doi: 10.1007/s10654-019-00554-x. Epub 2019 Sep 5.
Identification of individuals at high risk of dementia has usually focused attention on the clinical concept of mild cognitive impairment (MCI), which captures an intermediate state between normal cognitive ageing and dementia. In many countries age specific risk of dementia has declined, but whether this is also the case for subclinical cognitive impairment is unknown. This has important implications for prevention, planning and policy. Here we describe subclinical cognitive impairment and mild dementia prevalence changes, in the UK, over 2 decades. The Cognitive Function and Ageing Studies have examined the full spectrum of cognition, from normal to dementia, in representative populations of people aged ≥ 65 years in the UK over the last 2 decades 7635 participants were interviewed in CFAS I in Cambridgeshire, Newcastle, and Nottingham in 1991, with 1457 being diagnostically assessed. In the same geographical areas, the CFAS II investigators interviewed 7796 individuals in 2011. Using established criteria, the population was categorised into seven groups: no cognitive impairment, Mild cognitive Impairment (defined using consensus criteria), other cognitive impairment no dementia without functional impairment, OCIND with functional impairment, cognitive impairment (MMSE < 24 and no functional impairment), mild dementia (MMSE < 24 with functional impairment, not captured by CFAS dementia criteria), and CFAS dementia criteria. Multinomial logistic regression, adjusted for age and sex, was used to estimate the prevalence of impairment in both studies. Results were standardized to the age-sex specific UK and global population. There is a clear increase in the prevalence of other cognitive Impairment no Dementia (without functional impairment), with the purer MCI remaining stable. In the UK, mild dementia is estimated to fall from 520,704 cases (5.7%, 95% CI 3.8, 8.1) in 1991 to 315,142 (3.0%, 95% CI 2.4, 3.8) in 2011, cognitive impairment, has fallen from 1,225,984 (13.5%, 95% CI 10.1, 17.5) to 654,436 (6.3%, 95% CI 5.4, 7.3) cases. Using additional categories which reflect the continuum of cognitive decline and impairment in populations we see that the mildest dementia declines, but that there is stability in estimates of those who meet MCI criteria. Increases were found in the Other Cognitive Impairment no Dementia group. The decline observed in severe impairment thus seems to have resulted in larger proportions of the population in milder forms, seen alongside physical illnesses.
个体痴呆风险的识别通常集中在轻度认知障碍（MCI）的临床概念上，它捕捉了正常认知老化和痴呆之间的中间状态。在许多国家，痴呆的特定年龄风险已经下降，但亚临床认知障碍是否也是如此尚不清楚。这对预防、规划和政策具有重要意义。在这里，我们描述了过去 20 多年来英国亚临床认知障碍和轻度痴呆患病率的变化。认知功能和衰老研究（Cognitive Function and Ageing Studies）在过去 20 年中，在英国代表 65 岁及以上人群的代表性人群中，研究了从正常认知到痴呆的认知全貌。在 1991 年，剑桥、纽卡斯尔和诺丁汉的认知功能与衰老研究（CFAS I）中对 7635 名参与者进行了访谈，其中 1457 名参与者进行了诊断评估。在相同的地理区域，CFAS II 调查员于 2011 年对 7796 人进行了访谈。使用既定标准，将人群分为七组：无认知障碍、轻度认知障碍（使用共识标准定义）、无功能障碍的其他认知障碍且无痴呆、有功能障碍的 OCIND、认知障碍（MMSE<24 且无功能障碍）、轻度痴呆（MMSE<24 伴有功能障碍，未被 CFAS 痴呆标准捕获）和 CFAS 痴呆标准。使用多元逻辑回归，根据年龄和性别进行调整，估计了这两项研究中损伤的患病率。结果按英国和全球特定年龄和性别的人口进行了标准化。无功能障碍的其他认知障碍（痴呆）的患病率明显增加，而更纯粹的 MCI 保持稳定。在英国，轻度痴呆症估计从 1991 年的 520,704 例（5.7%，95%CI 3.8,8.1）下降到 2011 年的 315,142 例（3.0%，95%CI 2.4,3.8），认知障碍从 1,225,984 例（13.5%，95%CI 10.1,17.5）下降到 654,436 例（6.3%，95%CI 5.4,7.3）。使用反映人群认知衰退和损伤连续体的其他类别，我们发现最轻微的痴呆症下降，但符合 MCI 标准的人的估计值保持稳定。在其他认知障碍且无痴呆组中发现了增加。因此，严重损伤的减少似乎导致了更大多数人群处于更温和的形式，这与身体疾病同时存在。
