Compare methods

	Allostatic Load Index	Chains-of-Risk Model
Field	Social Epidemiology	Social Epidemiology
Family	Latent structure	Process / pipeline
Year of origin	1997	2003
Originator	Bruce McEwen & Eliot Stellar; Teresa Seeman, Burton Singer et al. (MacArthur Studies)	Diana Kuh & Yoav Ben-Shlomo (life-course glossary and conceptual models)
Type	Composite multi-system biomarker index of physiological dysregulation	Sequential-mediation model of linked life-course exposures
Seminal source	Seeman, T. E., Singer, B. H., Rowe, J. W., Horwitz, R. I., & McEwen, B. S. (1997). Price of Adaptation: Allostatic Load and Its Health Consequences. MacArthur Studies of Successful Aging. Archives of Internal Medicine, 157(19), 2259-2268.	Kuh, D., Ben-Shlomo, Y., Lynch, J., Hallqvist, J., & Power, C. (2003). Life course epidemiology. Journal of Epidemiology & Community Health, 57(10), 778-783.
Aliases	Allostatic Load Score, Cumulative Biological Risk Index, Multi-System Dysregulation Index, Allostatic Load	Chain of Risk Model, Accumulation of Risk Model, Risk Chains, Additive vs Trigger Chains
Related	4	3
Summary	The allostatic load index quantifies the cumulative biological cost of chronic stress by summing dysregulation across multiple physiological systems. McEwen and Stellar introduced 'allostatic load' in 1993 to name the wear and tear the body accrues when stress-response systems are repeatedly or chronically activated, extending the idea of allostasis (stability through change) over time. Seeman, Singer, Rowe, Horwitz, and McEwen operationalized it in the MacArthur Studies of Successful Aging in 1997, scoring older adults on biomarkers spanning cardiovascular, metabolic, neuroendocrine, and immune function and counting how many fell into a high-risk range, typically the worst quartile. The resulting count index predicted later cognitive and physical decline and cardiovascular disease, establishing allostatic load as a measurable marker of cumulative physiological risk that no single clinical test captures.	The chains-of-risk model is the specific life-course mechanism in which adverse exposures are linked in a sequence over time, so that one exposure raises the probability of the next, and the cumulative or final link bears on disease. Set out in Ben-Shlomo and Kuh's 2002 conceptual paper and defined in the Kuh, Ben-Shlomo, Lynch, Hallqvist, and Power 2003 life-course glossary, it models how early disadvantage can cascade — poor early circumstances leading to limited education, then to hazardous work or health behaviors, and finally to disease. Its signature analytic distinction is between an additive chain, in which each link independently adds to risk, and a trigger chain, in which the early links matter only because they lead to a final exposure that is the true cause. Chains-of-risk modeling thus treats the life course as a causal pathway to be decomposed, not a list of independent risk factors.