Examining chronic pain mechanisms with aging: an investigation in geriatric chronic low back pain
Date
2023
Authors
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Publisher
University of Delaware
Abstract
Background: Despite widespread research efforts, low back pain has remained the leading cause of disability worldwide for over three decades. Older adults are highly susceptible to the onset and persistence of chronic low back pain, which often causes debilitation and subsequent adverse health outcomes such as hospitalization, institutionalization, and mortality. Though older adults are disproportionately affected by chronic low back pain, they are routinely underrepresented in research that seeks to identify and intervene upon risk factors for this condition. Consequently, there are little to no known risk factors for chronic low back pain in older adults, which greatly restricts prognosis and intervention efforts in this vulnerable population. Two putative mechanisms for the development and maintenance of chronic low back pain have been proposed in young and middle aged adults: the fear-avoidance model of chronic pain, and central nervous system sensitization to pain. Neither mechanism has been empirically investigated in older adults with chronic low back pain, necessitating research to determine whether one or both mechanisms underlie the persistence of pain in this patient population. ☐ Purpose: We aim to: 1) investigate whether the fear-avoidance model of chronic pain contributes to the clinical course of chronic low back pain in older adults; 2) examine if older adults with chronic low back pain exhibit heightened central nervous system sensitization compared to pain-free older and younger adults; and 3) determine whether central nervous system sensitization is associated with clinical outcomes in older adults with chronic low back pain. ☐ Methods: Hypotheses regarding the validity of both mechanistic theories will be tested with two different study designs. The predictive validity of the fear-avoidance model of chronic pain will be examined in an observational cohort of older adults with chronic low back pain; this design affords the opportunity to infer whether baseline psychological risk factors from the fear-avoidance model of chronic pain influence future health outcomes. The face validity of the central nervous system sensitization theory will be examined in a comparative cross-sectional study that includes older adults with chronic low back pain as well as pain-free older and younger adults; this design provides the ability to quantify possible gradations of central nervous system sensitization that may be heightened in the context of senescence and compounded in the presence of chronic pain. Further, clinical health outcomes will also be collected among older adults with chronic low back pain in order to determine the clinical relevance of centrally mediated pain sensitivity. ☐ Significance: Determining the veracity of leading mechanistic theories of geriatric CLBP is essential in order to efficiently and effectively guide future research efforts to mitigate individual and societal burdens related to this condition. Our findings meaningfully extend prior evidence and temper assertions that psychological risk factors (from the fear-avoidance model of chronic pain) may wholly drive the geriatric CLBP experience. Simultaneously, our findings also provide preliminary support for central nervous system sensitization to pain as an impairment that develops with biological aging and potentially contributes to the development and maintenance of CLBP in older adults. This empirical support warrants future research to discover potentially modifiable mechanisms that induce the onset and persistence of centrally mediated pain sensitivity in the geriatric CLBP population.
Description
Keywords
Chronic low back pain, Pain physiology, Older adults, Chronic pain, Middle aged adults