MacDonald Stuart W S, Dixon Roger A, Cohen Anna-Lisa, Hazlitt Janine E
Department of Psychology, University of Victoria, Victoria, B.C., Canada.
Gerontology. 2004 Mar-Apr;50(2):64-81. doi: 10.1159/000075557.
Although recent cross-sectional findings indicate that markers of biological age (BA) mediate chronological age (CA) differences in cognitive performance, little is known about their influence on actual cognitive changes.
The purpose of this investigation is to examine CA and BA as predictors of 12-year cognitive change in a longitudinal sample of older adults.
Data from the Victoria Longitudinal Study (VLS) were examined for 125 adults between 67 and 95 years of age. Biomarkers, including visual and auditory acuity, grip strength, peak expiratory flow, blood pressure, and body mass index, were submitted to a factor analysis and a composite BA variable was computed based on factor loadings. Intraindividual change across 5 waves of measurement (3-year intervals) was examined as a function of CA and BA for 5 cognitive domains: verbal processing speed, working memory, reasoning, episodic memory, and semantic memory.
The latent structure of biomarkers was consistent with previous investigations of functional age and a common factor view of biological aging. Results of hierarchical linear modeling showed that BA predicted actual cognitive change (decline) independent of CA.
As a predictor of cognitive performance in late life, CA is a proxy for biological and environmental influences. We have shown that biological influences are independent predictors of actual cognitive change in older adults. This supports the view that cognitive decline is not due to aging per se, but rather is likely due to causal factors that operate along the age continuum.
尽管最近的横断面研究结果表明，生物学年龄（BA）标志物介导了认知能力方面的实际年龄（CA）差异，但对于它们对实际认知变化的影响却知之甚少。
本研究旨在考察在一个老年成年人纵向样本中，实际年龄和生物学年龄作为12年认知变化预测指标的情况。
对维多利亚纵向研究（VLS）中125名年龄在67至95岁之间的成年人的数据进行了分析。将包括视力、听力、握力、呼气峰值流速、血压和体重指数在内的生物标志物进行因子分析，并根据因子载荷计算出一个综合生物学年龄变量。以实际年龄和生物学年龄为函数，考察了在5个测量波次（间隔3年）中5个认知领域（言语加工速度、工作记忆、推理、情景记忆和语义记忆）的个体内变化。
生物标志物的潜在结构与先前关于功能年龄和生物衰老共同因素观点的研究一致。分层线性模型结果表明，生物学年龄独立于实际年龄预测了实际认知变化（下降）。
作为晚年认知表现的预测指标，实际年龄是生物和环境影响的一个代理指标。我们已经表明，生物影响是老年人实际认知变化的独立预测因素。这支持了以下观点，即认知衰退并非源于衰老本身，而是可能源于在年龄连续体上起作用的因果因素。
