Association of allostatic load with brain structure and cognitive ability in later life

Allostatic load (AL) has been proposed as a general framework for understanding the cumulative effects of life stress on individuals. Despite growing interest in AL, limited research has been conducted on aging samples. We consider the association of AL (operationalized by a range of inflammatory, cardiovascular, and metabolic measures) with a range of brain volume measurements and cognitive ability in a large cohort sample of older adults (n = 658, mean age = 72.5 years, standard deviation = 0.7) using structural equation modeling. AL was significantly inversely associated with total brain volume (range of standardized beta = -0.16 to -0.20) and white-matter volume (-0.35 to -0.36) and positively with hippocampal volume (0.10-0.15) but not gray-matter volume (0.04). AL was also significantly inversely associated with general cognitive ability (range beta = -0.13 to -0.20), processing speed (-0.20 to -0.22), and knowledge (-0.18 to -0.20) but not memory or nonverbal reasoning. The associations of AL with cognitive abilities were not mediated by these brain volume measures. AL did not predict cognitive change from age 11 to approximately age 73. The findings suggest a link between AL and later life brain health and cognitive functioning. (C) 2015 The Authors. Published by Elsevier Inc.