Department of Psychology, University of Victoria, Victoria, Canada.
J Gerontol B Psychol Sci Soc Sci. 2011 Jul;66 Suppl 1(Suppl 1):i59-70. doi: 10.1093/geronb/gbr039.
Chronological age is the most frequently employed predictor in life-span developmental research, despite repeated assertions that it is best conceived as a proxy for true mechanistic changes that influence cognition across time. The present investigation explores the potential that selected functional biomarkers may contribute to the more effective conceptual and operational definitions of developmental time.
We used data from the Victoria Longitudinal Study to explore both static and dynamic biological or physiological markers that arguably influence process-specific mechanisms underlying cognitive changes in late life. Multilevel models were fit to test the dynamic coupling between change in theoretically relevant biomarkers (e.g., grip strength, pulmonary function) and change in select cognitive measures (e.g., executive function, episodic and semantic memory).
Results showed that, independent of the passage of developmental time (indexed as years in study), significant time-varying covariation was observed linking corresponding declines for select cognitive outcomes and biological markers.
Our findings support the interpretation that cognitive decline is not due to chronological aging per se but rather reflects multiple causal factors from a broad range of biological and physical health domains that operate along the age continuum.
尽管反复声称，最好将年龄视为影响随时间变化的认知的真正机制变化的代理，但在寿命发展研究中，最常使用的预测因子仍是实际年龄。本研究探讨了选择的功能性生物标志物可能对发展时间的更有效概念和操作定义做出贡献的潜力。
我们使用来自维多利亚纵向研究的数据，探讨了可能影响晚年认知变化背后的特定过程机制的静态和动态生物或生理标志物。拟合多层次模型以测试理论上相关生物标志物（例如握力、肺功能）变化与特定认知测量（例如执行功能、情节和语义记忆）变化之间的动态耦合。
结果表明，独立于发展时间（以研究中的年数为指标）的流逝，观察到与特定认知结果和生物标志物的相应下降相关的显著时变协变。
我们的研究结果支持这样的解释，即认知能力下降不是由于实际年龄本身，而是反映了沿着年龄连续体运作的广泛的生物和身体健康领域的多个因果因素。
