Do Chronic Stressors lead to Physiological Dysregulation? Testing the theory of Allostatic Load

Objectives. We explore three questions: 1) Do chronic stressors predict physiological dyregulation? 2) Is that relationship moderated by characteristics of the individual and social environment? and 3) Do perceived levels of stress mediate the relationship between stressors and dysregulation? Methods. Data come from a nationally representative, longitudinal study of older Taiwanese (n=916). Regression models are used to examine the relationship between the number of life challenges (i.e., stressors) during 1996-2000 and physiological dysregulation (in 2000) based on 16 biomarkers that reflect neuroendocrine function, immune system, cardiovascular function, and metabolic pathways. We include interaction terms to test whether psychosocial vulnerability moderates the impact of stressors. Additional models evaluate the mediating effects of perceived stress. Results. We find a significant association between the number of stressors and physiological dysregulation only for those with high vulnerability. Even among this group, the magnitude of the effect is small. The level of perceived stress partly mediates the relationship between chronic stressors and physiological dysregulation. Conclusions. Our results provide some support for the theory of allostatic load, although the relationship between life challenges and physiological dysregulation is weak. The evidence also supports the stress-buffering hypothesis: the combination of low social position, weak social networks, and poor coping ability is associated with increases in the physiological consequences of life challenges.