Biological Age and 12-Year Cognitive Change in Older Adults: Findings from the Victoria Longitudinal Study

Abstract

Background: 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. Objective: 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. Methods: 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. Results: 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. Conclusions: 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.

Subjective Age and Cognitive Functioning: A 10-Year Prospective Study

“…On the other hand, this study is consistent with and extends prior research on the potential of alternative ways of measuring developmental time to explain older adults' cognition. 8,9 In addition, this study contributes to a growing body of research on the psychological and health-related implications of subjective age, given that it is the first to identify its association with cognitive outcomes. From a clinical standpoint, the present study suggests that subjective age assessment may inform about individuals at increased risk for potential cognitive deficits in old age.…”

“…7 Although chronological age is used as a key indicator of developmental changes and is considered as a risk factor for decrements in cognition, however, alternative ways of measuring developmental time could provide valuable insights about the mechanisms involved in older adults' cognitive functioning. 8,9 In this vein, studies have found that biological age, reflecting the functioning of critical physiological systems and processes of an individual relative to his or her own life span, contributes to cognitive functioning, independent of chronological age. 8,9 These findings are consistent with the view that older adults' cognition is influenced by a range of factors that operate along the age continuum.…”

“…8,9 In this vein, studies have found that biological age, reflecting the functioning of critical physiological systems and processes of an individual relative to his or her own life span, contributes to cognitive functioning, independent of chronological age. 8,9 These findings are consistent with the view that older adults' cognition is influenced by a range of factors that operate along the age continuum.…”

Episodic memory change in late adulthood: Generalizability across samples and performance indices

“…Despite stereotypes to the contrary, older adults are not a homogeneous group, and any single convenience sample may not be representative. Moreover, long-term cognitive aging processes may vary by basic sample characteristics, such as age, health, education, biological condition, and background (Bäckman et al, 2000;MacDonald, Dixon, Cohen, & Hazlitt, 2004;Wahlin, 2004). In longitudinal research, convenience samples may be especially vulnerable to initial selection and attrition effects.…”

Evaluation of Biological Aging Process – A Population-Based Study of Healthy People in China

“…Differences in physiological function among older adults are often considered one of the most important characteristics of senescence [6] . Subsequently, there are reported crosssectional and longitudinal studies which examined BA in terms of physical, physiological, biochemical, and hormonal changes associated with CA [7][8][9] . However, a BA model developed for one ethnic population might not be applicable to another ethnic population.…”