Gerontopole of Toulouse, Institute of Ageing, Toulouse University Hospital, Toulouse, France.
UPS/Inserm UMR1027, University of Toulouse III, Toulouse, France.
JAMA Netw Open. 2020 Dec 1;3(12):e2028634. doi: 10.1001/jamanetworkopen.2020.28634.
Plasma measurement of amyloid-β (Aβ) peptides has been associated with cognitive function, but evidence of its ability to identify cognitive decline is still scarce.
To investigate the associations between plasma Aβ42/40 and cognitive decline over time among community-dwelling older adults with subjective memory concerns.
DESIGN, SETTING, AND PARTICIPANTS: This multicenter cohort study used data from volunteers in the 5-year study Multidomain Alzheimer Preventive Trial (MAPT). Participants were aged 70 years or older and observed for a median (interquartile range) of 3.9 (2.0-4.0) years. Recruitment of participants started in May 2008 and ended in February 2011. Follow-up ended in April 2016. Data analysis was conducted from April to October 2020.
Plasma Aβ42 and Aβ40 were measured at 12 months for 448 participants (92.8%) and at 24 months for the rest. The moment of Aβ assessment was defined as the baseline for this study.
Cognitive function was assessed at 12, 24, 36, 48, and 60 months by a composite cognitive score based on 4 tests; Mini Mental State Examination (MMSE); Clinical Dementia Rating, sum of boxes; and Alzheimer Disease Cooperative Study-Activities of Daily Living. Mixed-effect linear regressions were performed.
A total of 483 participants (median [IQR] age, 76.0 [73.0-80.0]; 286 [59.2%] women) were analyzed. Of them, 161 (33.3%) were classified as low plasma Aβ42/40 (≤0.107). After adjusting for age, sex, education, body mass index, Geriatric Depression Scale score, apolipoprotein E ε4 genotype, and MAPT intervention groups, low plasma Aβ42/40 was associated with more pronounced decline in composite cognitive score (adjusted between-group mean difference: -0.20, 95% CI, -0.34 to -0.07; P = .004) and decline in MMSE score (adjusted between-group mean difference: -0.59; 95% CI, -1.07 to -0.11; P = .02) during the follow-up period compared with the group with an Aβ42/40 ratio greater than 0.107.
In this study, low plasma Aβ42/40 was associated with more pronounced decline in cognitive function (measured by multiple outcomes) over time. Findings suggest that plasma Aβ42/40 may be used to identify people at risk of cognitive decline, being an alternative to more complex and expensive measures, such as positron emission tomography imaging or cerebrospinal fluid measurement.
血浆中淀粉样蛋白-β（Aβ）肽的测量与认知功能有关，但证据表明其识别认知能力下降的能力仍然很少。
研究在有主观记忆问题的社区居住的老年人中，血浆 Aβ42/40 与随时间发生的认知下降之间的关联。
设计、地点和参与者：这项多中心队列研究使用了来自 5 年多领域阿尔茨海默病预防试验（MAPT）志愿者的数据。参与者年龄在 70 岁或以上，中位（四分位距）随访时间为 3.9（2.0-4.0）年。参与者于 2008 年 5 月开始招募，于 2011 年 2 月结束。随访于 2016 年 4 月结束。数据分析于 2020 年 4 月至 10 月进行。
448 名参与者（92.8%）在 12 个月时和其余参与者在 24 个月时测量了血浆 Aβ42 和 Aβ40。Aβ评估的时刻被定义为本研究的基线。
在 12、24、36、48 和 60 个月时，根据 4 项测试的综合认知评分、简易精神状态检查（MMSE）、临床痴呆评定总和量表和阿尔茨海默病合作研究-日常生活活动评估认知功能。进行了混合效应线性回归。
共分析了 483 名参与者（中位数[IQR]年龄，76.0[73.0-80.0]；286[59.2%]为女性）。其中，161 名（33.3%）被归类为低血浆 Aβ42/40（≤0.107）。在校正年龄、性别、教育程度、体重指数、老年抑郁量表评分、载脂蛋白 E ε4 基因型和 MAPT 干预组后，低血浆 Aβ42/40 与复合认知评分（校正组间平均差异：-0.20，95%CI，-0.34 至-0.07；P=0.004）和 MMSE 评分（校正组间平均差异：-0.59；95%CI，-1.07 至-0.11；P=0.02）的下降有关在随访期间与 Aβ42/40 比值大于 0.107 的组相比。
在这项研究中，低血浆 Aβ42/40 与认知功能（通过多种结果衡量）随时间的明显下降有关。研究结果表明，血浆 Aβ42/40 可用于识别认知能力下降风险较高的人群，这是对正电子发射断层扫描成像或脑脊液测量等更复杂和昂贵的测量方法的替代方法。
