Psychiatric Division, Sheba Medical center, Israel.
Alzheimer Dis Assoc Disord. 2011 Oct-Dec;25(4):312-6. doi: 10.1097/WAD.0b013e31820d880e.
This study examines the effect of age on rate of cognitive decline in different stages of dementia, of nursing home and assisted-living residents.
In this longitudinal study, the Mini Mental State Examination (MMSE) was used to measure rate of cognitive decline in subjects who were nondemented [Clinical Dementia Rating (CDR)=0; n=353], questionably demented (CDR=0.5; n=121), or frankly demented (CDR≥1; n=213) at baseline.
A generalized estimating equation was used to model the MMSE scores over time (mean follow-up 2.9±2.0 y). The generalized estimating equation model had the MMSE scores at successive follow-up time points as dependent variables and had linear and quadratic age, follow-up time from baseline, CDR at baseline, and all the interactions among them as independent variables, controlling for MMSE at baseline, sex, race, and education. The mean age of the entire sample was 85.2±7.4 years at baseline. There were no significant interactions of linear age effects with rate of cognitive decline. The analysis of interaction of quadratic age with rate of cognitive decline showed complex relationships: in the nondemented group, there was no substantial quadratic association of age with the rate of cognitive decline (P=0.13); in the questionable demented group, the oldest subjects declined relatively faster (P=0.02); and in the demented group, the youngest and oldest subjects tended to decline relatively less than subjects in the intermediate ages (P=0.07).
This study adds an additional aspect to the complexity of the association between age and rate of cognitive decline, showing that the direction and amplitude of this effect differs according to the stage along the course of cognitive decline.
本研究旨在探讨不同痴呆阶段、养老院和辅助生活居民的年龄对认知衰退速度的影响。
在这项纵向研究中，使用简易精神状态检查（MMSE）来衡量基线时无痴呆（临床痴呆评定量表 [CDR]=0；n=353）、可疑痴呆（CDR=0.5；n=121）或明显痴呆（CDR≥1；n=213）的受试者的认知衰退速度。
使用广义估计方程来对 MMSE 评分随时间的变化进行建模（平均随访 2.9±2.0 年）。广义估计方程模型将 MMSE 评分在连续随访时间点作为因变量，将线性和二次年龄、从基线开始的随访时间、基线时的 CDR 以及它们之间的所有交互作用作为自变量，同时控制基线时的 MMSE、性别、种族和教育程度。整个样本的平均年龄为 85.2±7.4 岁。线性年龄效应与认知衰退速度之间没有显著的交互作用。对二次年龄与认知衰退速度交互作用的分析显示出复杂的关系：在无痴呆组中，年龄与认知衰退速度之间没有实质性的二次关联（P=0.13）；在可疑痴呆组中，最年长的受试者衰退相对较快（P=0.02）；在痴呆组中，最年轻和最年长的受试者比年龄中等的受试者衰退相对较慢（P=0.07）。
本研究为年龄与认知衰退速度之间的关联的复杂性增添了一个新的方面，表明这种效应的方向和幅度因认知衰退过程中的阶段而异。
