Pain and aging: the emergence of a new subfield of pain research.

UNLABELLED: The pain and aging subfield has grown dramatically, including a 6-fold increase in publications over the last 2 decades. This subfield is based on the assumption that pain in older and younger adults differs in clinically and theoretically significant ways. If this were not the case, data from younger groups could be generalized to older persons, and the subfield would not be needed. This article considers the evidence for this assumption. Possible interpretations of the discrepant findings of age-related increases, decreases and stability in pain, including methodological limitations, challenges of gerontological research, and the possibility of nonuniform age-related variation, are discussed. Evidence is presented for several unique characteristics of geriatric pain: difficulty using Visual Analog Scales, increased vulnerability to neuropathic pain, decreased vulnerability to acute pain related to visceral pathology, prolonged recovery from tissue and nerve injury, including prolonged hyperalgesia, and differences in the relationships among psychosocial factors important in adjustment to chronic pain. However, without a theoretical framework, it is difficult to integrate these results in a heuristic manner. Further research is needed to elucidate the characteristics of geriatric pain, to examine the mechanisms for age-related patterns, and to develop and test the efficacy of age-tailored interventions. PERSPECTIVE: This article reviews the emerging subfield of pain and aging, discusses the interpretation of age-related patterns in pain, and presents several avenues for future research and subfield development. This could contribute to the continued growth of this subfield.