Does Chronic Pain Run in Families?

 Genetics, Parenting, and Stress May All Play a Role

Newswise, July 8, 2016– Can an increased risk of chronic pain be transmitted from parents to children? Several factors may contribute, including genetics, effects on early development, social learning, and more according to a report in the journal PAIN®, the official publication of the International Association for the Study of Pain (IASP). The journal is published by Wolters Kluwer.

Amanda L. Stone of Vanderbilt University, in Nashville, Tenn., and Anna C. Wilson of Oregon Health & Science University, in Portland, Ore., present a conceptual model of transmission of chronic pain, including potential mechanisms and moderating factors.

The researchers write, "Such a framework highlights chronic pain as inherently familial and intergenerational, opening up avenues for new models of intervention and prevention that can be family-centered and include at-risk children."

Proposed Explanations for Familial Transmission of Chronic Pain Risk
Knowing that offspring of parents with chronic pain are at increased risk of developing chronic pain, as well as the adverse mental and physical health outcomes associated with chronic pain, Drs. Stone and Wilson developed an "integrative conceptual model" to explore possible explanations for this risk.

The researchers identify five "plausible mechanisms" to explain the transmission of chronic disease risk from parent to child:

• Genetics. Children of parents with chronic pain might be at increased genetic risk for sensory as well as psychological components of pain. Research suggests that genetic factors may account for roughly half of the risk of chronic pain in adults.

• Early Neurobiological Development. Having a parent with chronic pain may affect the features and functioning of the nervous system during critical periods in early development. For example, a baby's development might be affected by the mother's stress level or health behaviors during and after pregnancy.

• Pain-Specific Social Learning. Children may learn "maladaptive pain behaviors" from their parents, who may act in ways that reinforce those behaviors. Catastrophizing—exaggerated responses and worries about pain—might be one key factor.

• General Parenting and Health Habits. Chronic pain risk could be affected by parenting behaviors linked to adverse child outcomes—for example, permissive parenting or lack of consistency and warmth. The parents' physical activity level and other health habits might also play a role.

• Exposure to Stressful Environment. There may be adverse effects from growing up in stressful circumstances related to chronic pain—for example, financial problems or parents' inability to perform daily tasks.

The model also identifies some "moderators" that might explain when and under what circumstances children are at highest risk of developing chronic pain. These include chronic pain in the other parent; the timing, course, and location of the parent's pain; and the children's characteristics, including their personal temperament.

"The outlined mechanisms, moderators, and vulnerabilities likely interact over time to influence the development of chronic pain and related outcomes in offspring of parents with chronic pain," Drs. Stone and Wilson note.

They hope their model will provide a framework to guide future research—toward the goal of developing effective prevention and treatment approaches for children of parents with chronic pain.

Click here to read “Transmission of risk from parents with chronic pain to offspring: an integrative conceptual model.”

Study Shows Pain Causes Older Adults to Develop More Inflammation Over a Longer Period of Time

Newswise, May 12, 2016 — When older relatives complain about their pains, show a little empathy, because new research suggests that as we age, we may all become more sensitive to pain. A small, preliminary University of Florida Health study has suggested for the first time that inflammation may occur more quickly and at a higher magnitude — and stays around longer — when older adults experience pain versus when younger adults experience pain.

This could mean that older adults could be at risk for developing chronic pain and may benefit from taking anti-inflammatories soon after an injury or procedure, according to the researchers.

Older adults often have a certain level of chronic inflammation in their bodies. But UF researchers found that when they induced pain in older adults, proteins associated with inflammation increased more than they did in younger participants and stayed in the bodies of older adults longer.

The researchers also found that anti-inflammatory cytokines, proteins that soothe inflammation, peaked later for older adults than younger adults. Their results were published in a previous issue of Experimental Gerontology.

“Older people go through painful procedures more often, and we wanted to research whether this accumulation of painful procedures or more acute pain episodes that older people encounter is bad,” said Yenisel Cruz-Almeida, Ph.D., MSPH, an assistant professor in the UF College of Medicine’s department of aging and geriatric research who also is affiliated with the UF Institute on Aging.

“If you have enough of those in a shorter period of time, does this predispose you to have chronic pain?”

When older adults have this kind of elevated inflammatory response, they’re more likely to have pain generated in the periphery of the body — their tissue and limbs outside of the spinal cord and brain, said the study’s senior author Joseph Riley, Ph.D., director of the pain clinical research unit in the UF Pain Research and Intervention Center of Excellence.

“If older adults are more likely to have these pain messages sent through the spinal cord to the brain, and the nervous system is being adapted to go through these changes, they may become more pain prone,” said Riley, also a professor in the UF College of Dentistry’s department of community dentistry and the UF College of Public Health and Health Professions’ department of clinical and health psychology.

While the study does not establish whether accumulation of acute pain predisposes older adults to chronic pain, the researchers say their findings suggest this is a possibility, and it’s the first step in pain research to further understand the relationship between pain and aging.

The researchers said the study’s sample size, though small, was more than adequate to demonstrate large differences between the older and younger adults they tested.

The differences in inflammation within each group varied very little compared with the overall difference between the two groups, which suggests the populations they sampled were very different and there was little chance of sampling error, Riley said.

Cruz-Almeida and Riley studied eight healthy older adults, whose average age was 68, and nine healthy younger adults, whose average age was 21.

None of the participants had illnesses such as diabetes or hypertension. During an initial visit, researchers induced pain in the participants in two ways, either using heat applied to the feet or a cold ice bath.

The first session determined how sensitive the participants were to pain. Determining a tolerable temperature allowed the researchers to recreate the same amount of pain for each participant in the subsequent sessions.

Participants rated their pain on a scale from 1 to 10. The researchers were aiming to induce pain to a Level 4 — a level that created the painful stimuli the researchers needed, but didn’t dissuade the participants from returning for the other visits required in the study.

To study inflammation in the blood, the scientists inserted a catheter into each participant before inducing pain. That allowed them to collect the participant’s blood before the pain stimulus and then at three, 15, 30, 45, 60 and 90 minutes after the stimulus.

These blood samples allowed the researchers to study inflammatory markers in the blood, finding that older adults had higher levels of inflammation when pain was induced than the younger adults.

Riley said activation of the immune system and increased inflammation are not necessarily harmful, but it’s important to understand how the length of time the immune system is activated affects the body.

“We think that the longer you have the immune system activated, having these elevated inflammatory cytokines, the more this activation can alter the homeostasis of the body. Usually an imbalance like that can be associated with autoimmune disorders, which also increase with age,” Cruz-Almeida said.

“But the truth is we don’t know what the direct implications would be. We think low-grade inflammation is related to endocrine abnormalities such as diabetes and the development of heart problems. … We need to keep looking and doing future research.”

Riley said immediate implications of the research for patients could be to attack pain quickly with anti-inflammatory medication.

“Early treatment of an injury even with over-the-counter anti-inflammatories may be a good idea,” Riley said. “It’s those first few days of bombarding the central nervous system with pain signals that has a bigger effect (on the body).”

50 Million American Adults Have Significant Chronic or Severe Pain

Newswise, August 25, 2015– Nearly 50 million American adults have significant chronic pain or severe pain, according to a new study prepared by National Institutes of Health’s National Center for Complementary and Integrative Health (NCCIH), which appears this month in The Journal of Pain, http://www.jpain.org, published by the American Pain Society, http://www.americanpainsociety.org.

Based on data from the 2012 National Health Interview Survey (NHIS), the study estimates that within a previous three-month period, 25 million U.S. adults had daily chronic pain, and 23 million more reported severe pain. Those with serious pain need and use more health care services and suffer greater disability then persons with less severe pain.

The annual NHIS study is conducted by the U.S. Centers for Disease Control and Prevention (CDC) and surveys tens of thousands of Americans about their overall health and illnesses. 

The 2012 NHIS studied asked participants about the frequency and intensity of pain experienced in the last 3 months.

The findings also showed that half of individuals with the most severe pain still rated their overall health as good or better, and there were associations between pain severity and race, ethnicity, language preference, gender, and age. Women, older individuals, and non-Hispanics were more likely to report any pain, but Asians less likely. Also, the study showed the impact of gender on pain is influenced by race and ethnicity.

In an NIH news release, Richard L. Nahin, Ph.D., M.P.H., lead epidemiologist for NCCIH and author of the analysis said: “This report begins to answer calls for better national data on the nature and extent of the pain problem. The experience of pain is subjective. 

It’s not surprising then that the data show varied responses to pain even in those with similar levels of pain. Continuing analyses of these data may help identify subpopulations that would benefit from additional pain treatment options.”

Publication of the NIH study follows the recent “Pain Research Agenda for the 21st Century,” published in December in The Journal of Pain, in which The American Pain Society identifies promising but underfunded approaches to develop new treatments and to help make currently used pain medications safer and more effective. 

However, APS believes breakthrough new treatments will not become available unless more resources are devoted to pain research. Its Pain Research Agenda states: “The most direct path to achieving dramatic advances in pain treatment is through substantially increased investment in pain research and education, which would enable the pursuit of an aggressive translational pain-research agenda.”

About the American Pain Society
Based in Chicago, the American Pain Society (APS) is a multidisciplinary community that brings together a diverse group of scientists, clinicians and other professionals to increase the knowledge of pain and transform public policy and clinical practice to reduce pain-related suffering. APS is the professional home for investigators involved in all aspects of pain research including basic, translational, clinical and health services research to obtain the support and inspiration they need to flourish professionally. APS strongly advocates expansion of high quality pain research to help advance science to achieve effective and responsible pain relief. For more information on APS, visit www.americanpainsociety.org.