Chronic pain and its persistence can be linked with several different socio-demographic factors. One such factor is socio-economic status (SES) or income level. Though this link is important and may seem obvious to some, the research about this topic is surprisingly sparse – especially in the United States and especially as it relates to pain. The research that is available was conducted in Europe, namely the Scandinavian counties, or Canada. In the United States, research into this problem focuses mainly on overall health and how it is affected by one's income level. Because persistent pain is a chronic and common health condition, research that covers chronic health conditions can be expanded to include chronic pain.

What is the link between health and income?  

• Differences in income are associated with many differences in lifestyles and life conditions in general.

• Health inequality is only one of these differences associated with income.

• People with lower socio-economic status are usually considered sicker and have more chronic health problems and fewer opportunities for treatment.

• People with lower socio-economic status also usually report lower self-rated health. A self-rated health score is determined by a series of questions that asks a person to rate their own health in terms of whether they view it as poor, good, or excellent.

• Research shows that self-rated health scores are a very good and reliable indicator of a person's mortality. For example, if a person rates their health poorly, even if they are not traditionally sick, they are more likely to die sooner. If a person rates their health as excellent, it is a good indicator that they will live longer.

Why do these differences exist? As much of the research that exists was done in such countries as Norway, Finland, The Netherlands, and Canada, it is difficult to draw a direct comparison from these findings and apply them to the population of the United States. Norway, Finland, The Netherlands, and Canada have universal health care, which in theory means that everyone has equal access to health care. The United States has a different ethnic and cultural population and a different health care system.

Despite universal health care, the studies from Norway, Finland, The Netherlands, and Canada show that people with lower incomes are sicker and have more chronic health problems, including chronic pain. Why does this still occur, even in countries where people have access to health care?

• Much of the available research shows that income inequality is only part of the problem. Some researchers say that racial and ethnic differences contribute to the inequality. Racial and ethnic disparities were discussed in last month's segment. Click here to read more.
• Other researchers believe that lower education levels in lower income groups are the real problem.  People with less education may find the health care system difficult to use.  They may not be able to read well enough to understand health care instructions or information.
• Some researchers believe that access is the key issue. People from lower income levels are usually uninsured or underinsured, making them more reluctant to seek out medical care because they cannot afford it. This access problem can cause chronic conditions to persist and worsen.
• Language and cultural barriers have also been presented as reason for existing disparities.  This is especially true for those people who identify with a specific racial, ethnic or immigrant minority group.

Where do we go from here? Identifying, understanding, and studying this problem are only the first steps to ending this disparity.  What actually can be done?  Trying to eliminate socioeconomic disparity is like trying to eliminate poverty. 

Aside from the very obvious step of completing more research on this subject, especially related to chronic pain, perhaps we can follow the example of the Nordic countries and Canada and first realize this is a real problem for portions of the U.S. population and attempt to do something about it.

Intervention methods could also be used to help figure out how to solve the problem. One intervention trial in Indianapolis focused on self-management for people with back pain living in an inner-city area. This intervention trial promoted self-management through three group sessions and telephone follow-up that focused on understanding back pain, increasing physical activity, and dealing with fears and frustrations. Those people that participated in this self-management trial improved and maintained their functional status. Perhaps self-management treatment is the key to helping low socio-economic groups of people.

Also, as many of these low income groups of people are part of minority and immigrant groups, perhaps non-traditional treatments are key. Prayer, heat, and topical ointments were found to be helpful for African American and Hispanic patients complaining of arthritic pain. Non-traditional treatments for pain may be helpful to specific groups of people in low income groups. Elisa Martinez is a master's candidate at Drexel University School of Public Health in Philadelphia, Penn. Upon graduation, she hopes to continue work in chronic disease research, focusing on health inequities and disparities.

Elisa Martinez is a master's candidate at Drexel University School of Public Health in Philadelphia, Penn. Upon graduation, she hopes to continue work in chronic disease research, focusing on health inequities and disparities.

Additional Resources for Socio-economic Disparities:

Bill-Harvey, D.; Rippey, R.M.; Abeles, M.; and C.A. Pfeiffer (1989). "Methods used by urban, low-income minorities to care for their arthritis." Arthritis Care & Research. 2 (2): 60-4.

Damush, Teresa M.; Weinberger, Morris; Perkins, Susan M.; Rao, Jaya K.; Tierney, William M.; Qi, Rong; and Daniel O. Clark (2003). "The Long-term Effects of a Self-management Program for Inner-city Primary Care Patients With Acute Low Back Pain." Arch Intern Med. 163: 2632-2638.

Hayward, Mark D.; Miles,Toni P.; Crimmins, Eileen M.; Yu Yang (2000) "The Significance of Socioeconomic Status in Explaining the Racial Gap in Chronic Health Conditions." American Sociological Review, Vol. 65 (6): 910-930.

  Koster, Annemarie; Bosma, Hans; Kempen, Gertrudis I. J. M.; van Lenthe, Frank J.; van Eijk, Jacques Th. M.; and Johan P Mackenbach (2004). "Socioeconomic inequalities in mobility decline in chronic disease groups (asthma/COPD, heart disease, diabetes mellitus, low back pain): only a minor role for disease severity and comorbidity." Journal of Epidemiology and Community Health. 58: 862-869.

  Lynch, John W.; Smith, George Davey, Kaplan, George A.; and James S House (2000) "Income inequality and mortality: importance to health of individual income, psychosocial environment, or material conditions." BMJ. 320:1200-1204. Marra, C.A.; Lynd, L.D.; Esdaile, J.M.; Kopec, J.; and A. H. Anis (2004). "The impact of low family income on self-reported health outcomes in patients with rheumatoid arthritis within a publicly funded health-care environment." Rheumatology 43(11):1390-1397.

 Mauksch, Larry B.; Katon, Wayne J.; Russo, Joan; Tucker, Suzanne M.; Walker, Edward; and Janet Cameron (2003). "The Content of a Low-income, Uninsured Primary Care Population: Including the Patient Agenda." The Journal of the American Board of Family Practice. 16: 278-289.

Saastamoinen, Peppiina, Leino-Arjas, Paivi, Laaksonen, Mikko, and Eero Lahelma (2005). "Socio-economic differences in the prevalence of acute, chronic and disabling chronic pain among ageing employees." Pain. Vol. 114 (3): 364-371.

Sturm, Roland and Carole Roan Gresenz (2002). "Relations of income inequality and family income to chronic medical conditions and mental health disorders: national survey." BMJ. 324: 20.

Volinn, Ernest (1997). "The Epidemiology of Low Back Pain in the Rest of the World: A Review of Surveys in Low- and Middle-Income Countries." Spine. Vol. 22(15): 1747-1754.