Immunosenescence, the age-related decline of the immune system, may be affected by environmental or psychological stressors which, combined with endocrinosenescence, may accelerate the decline of immune-related health. Because making critical decisions, especially those related to health and medicine, is a common source of stress, it may have unforeseen and particularly deleterious effects on the immune system in elderly populations. This project examined the immunological consequences of participating in a stressful decision-making task in order to elucidate more precisely how stress and immune function interact with age. This immunological profile may aid both in the design of medical and health decisions to minimize their adverse effects on immune function, and in identifying populations at particular immunosenescent risk during such immune-related events as vaccination or illness. Researchers observed a sudden and startling drop in cognitive ability after age 60 using measures such as the Minimental, Listening-span, mathematical ability, memory, and decision making. Surprisingly, while greater age predicted increased subjective stress, age did not predict salivary cortisol, a measure of biological stress. Subjective and biological stresses were not related, and subjective stress and education--not biological stress--were associated with decision-making ability.
Further, subjective stress was strongly associated with subsequent memory recall of decision-making elements, but only for the older adults. As education was strongly negatively correlated with subjective stress, higher levels of education may buffer individuals against the effects of subjective stress on cognitive abilities, including decision-making and memory. Thus subjective stress may play a critical role in decision-making and memory distinct from biological stress. Current analysis of genetic data may further elucidate the interplay of subjective and biological stress in influencing decision-making. A manuscript has been submitted.