LAS VEGAS — The prevalence of many types of pain increases with age, and the pain often becomes more widespread and disabling among older adults. Chronic pain may also be associated with accelerated aging, with potential effects on biological and psychosocial processes.
“Pain processing seems to change as we age, with pain-modulating systems shifting toward more pain facilitation rather than pain inhibition,” said Roger Fillingim, PhD, director of the University of Florida’s Pain Research and Intervention Center of Excellence in Gainesville.
However, simply assuming that all pain worsens as individuals age is not accurate, he cautioned. In fact, the perception of pain intensity appears to vary by pain type, with people becoming less sensitive to cutaneous pain and strikingly less sensitive to visceral pain as they get older, while becoming more sensitive to pressure pain and strikingly more sensitive to tonic muscle pain.
It is important for clinicians to view the process of chronic pain and aging in a biopsychosocial context, explained Dr. Fillingim. He reviewed several biological and behavioral markers of age that researchers believe may be related to changes in how pain is experienced. One such biological marker is length of telomeres, which are the protective caps on the ends of chromosomes that researchers know shorten with cell replication. Other biological markers include DNA methylation, inflammation, peripheral nerve structure and function, and gray matter atrophy.
“We know we tend to lose more function on myelinated nerves as we age, which can open the door for more tonic pain input,” said Dr. Fillingim. “Endogenous opioid function is also reduced as we age. Brain imaging studies show that older adults are less able to activate mu opioid receptors in response to experimental pain stimuli.”
Behavioral markers of age thought to influence pain include walking speed, strength, balance, cognitive function, and sensory loss.
Researchers have observed associations between poorer cognitive performance and pain. “This relationship may go both ways. Many brain systems that support cognitive function could also be involved in pain modulation,” explained Dr. Fillingim.
He suggested that it is helpful to conceptualize how pain systems function as a modulatory balance in how pain is processed and perceived; some systems amplify pain whereas others decrease pain. “When we are younger we have a nice balance between facilitation and inhibition. As we age, we get much better at turning up the gain on pain,” he said.
Psychological factors that affect pain include coping ability, fear avoidance, patient expectation, and pain catastrophizing. Social components such as greater isolation among older adults, and more limited socioeconomic resources and social support systems are also factors.
Bias in Pain Treatment for Older Adults
Despite being at increased biopsychosocial risk for chronic pain, older adults are at greater risk of receiving insufficient treatment for their pain.
In a study that involved individuals who presented to an emergency department with pain, older adults were less likely to receive analgesics for their pain or were more likely to experience delays in the provision of analgesics.
The reason for this is several-fold, explained Dr. Fillingim. Potential contributors include reluctance on the part of older patients to report their pain due to age-related stoicism; acceptance on the behalf of healthcare providers that pain is normal in older adults; fear of pharmacologic interventions from both providers and patients (fall risk, polypharmacy); low expectations on the part of the provider about the efficacy of treatments in older adults; and provider bias against the treatment of pain in older adults.
“If an older adult presents with back or knee pain, clinicians may be more likely to think it goes with the territory—‘That’s what you get for reaching 70’—whereas if a 35-year-old showed up with the same problems, the clinician is more responsive,” said Dr. Fillingim. “But when pain is impacting quality of life, it really shouldn’t be accepted as normal or okay.”
Furthermore, available evidence, although limited, suggests that most pain treatments have similar efficacy among older adults.
Implications for Clinical Practice
“The experience of pain in older adults is sculpted by a dynamic interaction between biopsychosocial factors, so optimal treatment requires healthcare providers to take all of these factors into account,” emphasized Dr. Fillingim.
Patient and healthcare provider education is critical to treatment success, he added. Simple anti-inflammatory interventions, such as vitamin D and omega-3 supplements, may be helpful for older adults with chronic pain, as well as physical and psychosocial interventions.
“We do need to keep in mind that these treatments will need to be tailored to older populations as well as to fit the appropriate cognitive and physical abilities of the individual patient,” said Dr. Fillingim.