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RESEARCH AND PRACTICE |
The authors are with the Centers for Disease Control and Prevention, National Center for Chronic Disease Prevention and Health Promotion, Division of Adult and Community Health.
Correspondence: Request for reprints should be sent to Tara W. Strine, MPH, Division of Adult and Community Health, Centers for Disease Control and Prevention, 4770 Buford Highway NE, Mail Stop K-66, Atlanta, GA 30341 (email: tws2{at}cdc.gov).
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ABSTRACT |
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 TOP ABSTRACT INTRODUCTIONMETHODSRESULTSDISCUSSIONReferences |
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Objectives. We examined the association between pain-related activity difficulty (PRAD) in the past 30 days and health-related quality of life, health behaviors, disability indices, and major health impairments in the general US population.
Methods. We obtained data from 18 states in the 2002 Behavioral Risk Factor Surveillance System, an ongoing, cross-sectional, state-based, random-digit-dialed telephone survey of noninstitutionalized adults aged 18 years or older.
Results. Nearly one quarter of people in the 18 states and the District of Columbia reported at least 1 day of PRAD in the past 30 days. PRAD was associated with obesity, smoking, physical inactivity, impaired general health, infrequent vitality, and frequent occurrences of physical distress, mental distress, depressive symptoms, sleep insufficiency, and anxiety symptoms. Moreover, a general dose–response relationship was noted between increased days of PRAD and increased prevalence of impaired health-related quality of life, disability indices, and health risk behaviors.
Conclusion. Pain negatively influences various domains of health, not only among clinical populations, but also in the general community, suggesting a critical need for the dissemination of targeted interventions to enhance recognition and treatment of pain among adult community-dwellers.
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INTRODUCTION |
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TOPABSTRACTINTRODUCTIONMETHODSRESULTSDISCUSSIONReferences |
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Notably, people who live with persistent pain are 4 times more likely than those without pain to suffer from depression or anxiety and more than twice as likely to have difficulty working.6 Conditions associated with pain cost US companies approximately $61.2 billion per year, primarily because of impaired work performance.4 In addition, pain accounts for 20% of medical visits and 10% of prescription drug sales.7 In declaring 2001 to 2011 to be the "Decade of Pain Control and Research," Congress provided much-needed recognition of this frequently chronic and potentially disabling condition.8,9
Pain is widely accepted as one of the most important determinants of quality of life because of its widespread adverse effects, including diminishing mental health and well-being and impairing the individual’s ability to perform daily activities.3 Although numerous studies have examined the association between pain and health-related quality of life (HRQOL) in countries outside the United States and in clinical populations suffering from specific conditions, no studies were found examining associations between days of pain-related activity difficulty (PRAD), HRQOL, health behaviors, disability indices, and major impairments among US community-dwellers. To examine these associations, data were analyzed from the 2002 survey of the Behavioral Risk Factor Surveillance System (BRFSS).
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METHODS |
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TOPABSTRACTINTRODUCTIONMETHODSRESULTSDISCUSSIONReferences |
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Survey participants’ responses to 8 HRQOL questions with demonstrated validity and reliability for population health surveillance12 were examined. Respondents were asked to rate their general health as excellent, very good, good, fair, or poor. These responses were dichotomized into (1) excellent, very good, or good and (2) fair or poor. The remaining 7 questions asked respondents to estimate the frequency of various conditions during the previous 30 days: "How many days was your physical health, which includes physical illness or injury, not good?" (physical distress); "How many days was your mental health, which includes stress, depression, and problems with emotions, not good?" (mental distress); "How many days did you feel sad, blue, or depressed?" (depressive symptoms); "How many days did you feel worried, tense, or anxious?" (anxiety symptoms); "How many days did you feel you did not get enough rest or sleep?" (sleep insufficiency); "How many days have you felt very healthy and full of energy?" (vitality); and "How many days did pain make it difficult to do your usual activities?" (PRAD). With the exception of the PRAD question, responses were dichotomized into 0 to 13 (infrequent) and 14 to 30 (frequent) unhealthy days in each domain, or, in the case of vitality, healthy days. This dichotomy has been used in previous research,13–15 with the term "frequent" representing the respondent’s status for a substantial portion of the month. PRAD days were categorized into 0 days (no PRAD), 1 to 13 days (infrequent PRAD), and 14 to 30 days (frequent PRAD). Specifically, this study examined the association of these 3 PRAD categories with the 7 other HRQOL measures.
The BRFSS also asks respondents questions about their smoking status, physical activity, height and weight, and alcohol consumption. A current smoker was defined as someone who had smoked at least 100 cigarettes in their lifetime and who indicated they are presently a smoker. People were considered to be physically inactive if they did not participate in any leisure time physical activity or exercise during the previous 30 days. Body mass index was calculated as weight in kilograms divided by the square of height in meters. People were considered obese if their body mass index was 
30 kg/m2. Men were considered heavy drinkers if they drank more than 2 drinks per day, while women were considered heavy drinkers if they drank more than 1 drink per day.16
The HRQOL module also contains a section on disability. To investigate the association between PRAD and disability, we examined the prevalence and odds of disability among the 3 levels of PRAD. To be included in this analysis, the respondent must first have answered "yes" or "no" to both of the following questions: "Are you limited in any way in any activities because of physical, mental, or emotional problems?" or "Do you have a health problem that requires you to use special equipment, such as a cane, a wheelchair, a special bed, or a special telephone?" People who responded "yes" to either question were considered to have a disability.17 Among those with a disability, an examination of the prevalence and odds of personal care and routine needs assistance by PRAD category was conducted.
In addition, among those with a disability, we assessed the prevalence of PRAD by reported primary impairment or health problem. For this subanalysis, respondents with a disability were asked: "What is your major impairment or health problem?" Discrete categories to which the interviewer assigned participants’ responses include: arthritis/rheumatism, back/neck problems, fractures, bone/joint injury, walking problem, lung/ breathing problem, hearing problem, eye/vision problem, heart problem, stroke problem, hypertension, diabetes, cancer, depression/anxiety/ emotional problem, and other impairments/ problem. Respondents could indicate only 1 primary impairment.
Of the 84 904 respondents in the 18 states and the District of Columbia, 5098 (6.0%) were excluded because of missing information for study variables (1457 because of missing sociodemographic information, 3641 because of missing PRAD data), yielding data from 79 806 respondents available for analysis. For the disability subanalysis, a total of 79 356 respondents provided sufficient information to determine disability status. Of these, 14 814 were considered to have a disability. A primary impairment or health problem was reported by 14 252 of these respondents.
SUDAAN software (version 9; Research Triangle Institute, Research Triangle Park, NC) was used in the analyses to account for the complex sample design and to calculate prevalence estimates, standard errors, 95% confidence intervals (CIs), unadjusted odds ratios, and adjusted odds ratios. All statistical inferences were based on a significance level of P < .05. Unconditional logistic regression analysis was used to calculate adjusted odds ratios and conditional marginals. All adjusted models contained gender, age, race/ethnicity, marital status, education, and employment status.
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RESULTS |
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TOPABSTRACTINTRODUCTIONMETHODSRESULTSDISCUSSIONReferences |
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. People aged 18 to 24 years were less likely to report frequent PRAD than those aged 25 years or older. Moreover, women were significantly more likely to report frequent PRAD than men, whereas White non-His-panic respondents were more likely to report frequent PRAD compared with Black non-Hispanic or Hispanic respondents. Additionally, people with less than a high-school education were more likely to report frequent PRAD than those with greater than a high-school education, whereas those previously married were significantly more likely to report frequent PRAD than those currently married. Finally, people who were unemployed, unable to work, retired, or a student or homemaker were significantly more likely to report frequent PRAD than those currently employed.
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). For example, 7.6% (SE = 0.2) of people with no PRAD days in the past 30 days reported fair or poor general health, whereas 16.6% (SE = 0.7) of those with infrequent PRAD and 36.0% (SE = 1.2) of those with frequent PRAD reported fair or poor general health. This pattern was true for frequent physical distress (3.3% [SE = 0.2], 8.9% [SE = 0.7], and 45.8% [SE = 2.0]), frequent mental distress (6.2% [SE = 0.3], 10.3% [SE = 0.8], and 28.1% [SE = 1.8]), frequent depressive symptoms (4.6% [SE = 0.2], 8.5% [SE = 0.5], and 23.6% [SE = 1.1]), frequent sleep insufficiency (20.0% [SE = 0.3], 29.9% [SE = 0.8], and 52.6% [SE = 1.3]), frequent anxiety symptoms (10.1% [SE = 0.3], 18.4% [SE = 0.7], and 37.3% [SE = 1.2]), and infrequent vitality (23.9% [SE = 0.4], 42.0% [SE = 0.9], and 66.0% [SE = 1.2]).
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). Additionally, women reporting infrequent PRAD were significantly more likely to drink heavily than those with no PRAD days (adjusted odds ratio = 1.3); however, those reporting frequent PRAD were significantly less likely to drink heavily than those with infrequent PRAD (adjusted odds ratio = 0.5) and were equally as likely to drink heavily as those with no PRAD. Finally, people reporting frequent PRAD were significantly less likely than those reporting no PRAD or infrequent PRAD to be physically active (adjusted odds ratio = 2.0).
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). Adults reporting frequent PRAD were 16.7 times more likely to report a disability than those reporting no PRAD. Among adults with a disability and frequent PRAD, 20.0% required help with personal care activities, and 48.5% required help with routine needs such as household chores and shopping.
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displays the distribution of PRAD days among respondents reporting disability by primary impairment or health problem. With the exception of hearing problems, eye/vision problems, and lung/breathing problems, at least 50% of respondents with each disabling condition examined reported at least 1 day of PRAD in the past 30 days, and 20% or more of respondents with each condition reported frequent PRAD. More specifically, over 40% of those reporting back or neck problems, arthritis or rheumatism, diabetes, hypertension, and cancer reported frequent PRAD, whereas between 30% and 40% of respondents reporting disability related to walking problems, fractures or bone/joint injuries, strokes, heart problems, and depression, anxiety, or emotional problems reported frequent PRAD.
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DISCUSSION |
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TOPABSTRACTINTRODUCTIONMETHODSRESULTSDISCUSSIONReferences |
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Notably, this study also indicates that people with disability who selected their primary impairment or health problem to be depression, anxiety, or emotional problems reported frequent PRAD at rates comparable to people reporting disability caused by cardiovascular conditions, such as heart problems and strokes. This psychological link to pain is important because research has suggested that psychological factors and coping skills may influence susceptibility to chronic pain and pain control.22–26 Notably, psychological factors may be more important than many physiological variables in the development of pain, particularly in people with back and neck pain.24 Previous research also suggests that psychiatric disorders, such as anxiety and depression, can potentially decrease pain thresholds and increase functional impairment.27 Additionally, pain may increase the somatic symptoms of depression (fatigue, insomnia) in addition to affecting the duration and probability of recurrence of depressive illness.28
As has been reported previously in clinical samples and population studies conducted outside of the United States, pain was associated with female gender, unemployment, divorce, low educational attainment, and increased age.29–40 Given that the US population is rapidly aging,41 the association between age and pain is particularly noteworthy. Additionally, consistent with research conducted by Portenoy et al.34, which indicates that Whites experience pain for a longer duration but with less intensity than Black non-Hispanics or Hispanics, this study suggests that White non-Hispanic respondents were significantly more likely to report frequent PRAD than Black non-Hispanic or Hispanic respondents.
Notably, our results also indicate that the prevalence of frequent PRAD decreases with education, whereas infrequent PRAD is associated with higher educational attainment. It could be speculated that the inverse relationship between frequent PRAD and education may be linked to increased likelihood of having employment that may require physical exertion, an inability to seek medical care for pain management, or conversely, an inability to achieve advanced education as a result of pain-related disability. The increase of infrequent PRAD days with increased education may be attributable to sporadic pain sources such as tension headaches or stress-related musculoskeletal syndromes, which may be more prevalent among those with higher education because of job stress. Additionally, those who were unemployed, unable to work, retired, or homemakers or students were significantly more likely to report frequent PRAD than those currently employed. Notably those who were unable to work were 17.5 times more likely to report frequent PRAD than those employed. This finding, in combination with the high prevalence of disability among those with frequent PRAD (68.6%), emphasizes the significant association between frequency of pain and disability. Unfortunately, because of the cross-sectional design, we cannot determine the temporal sequence of PRAD with either work status or educational attainment. Future longitudinal studies are needed to investigate these aspects appropriately.
A significant association between PRAD days and behavioral risk factors such as smoking, obesity, and physical inactivity was also observed. Results of recent studies have suggested a possible relationship between cigarette smoking and back pain and various neurological, cardiovascular, and pulmonary disorders.42–44 In addition, studies indicate that physical inactivity and obesity are linked to sleep apnea, back pain, osteoarthritis, and gallstones as well as cancers of the colon, breast, uterus, and prostate–many of which are associated with pain.45 Reducing these risk behaviors may influence the quantity and intensity of pain for some people. For example, among adults with osteoarthritis, increasing physical activity has been shown to reduce pain in the long term. Subsequently, physical function improves and the risk of disability declines as people with osteoarthritis become more active.46–48
Chronic widespread pain in the community generally has a fair prognosis,33,49,50 with 1 US population-based study indicating a 32.5% recovery rate over an 8-year period.49 In this study, at least 45% of disabled respondents who reported back or neck problems or arthritis and rheumatism as their major impairment also reported frequent PRAD, despite the availability of evidence-based interventions reported to significantly reduce pain among people with these conditions. Various pharmacological and non-pharmacological interventions, including medications (muscle relaxants and non-steroidal, anti-inflammatory drugs), therapeutic exercise programs, "back schools," and spinal manipulative therapy, can successfully reduce pain among patients with back and neck pain.51 Among people with arthritis and other rheumatic conditions, self-management education and physical activity programs have yielded 20% to 25% reductions in pain in addition to improving mental health and physical functioning.52
There are several limitations to this study. First, because BRFSS is a telephone survey, it may disproportionately exclude people of low socioeconomic status, a population known to have a lower HRQOL and higher mortality rates than the general population.53 Second, after examining the sociodemographic characteristics of persons included in the analysis versus those excluded (including those in the 18 states and the District of Columbia who were missing data and those in the remaining states and territories), this analysis may not be entirely representative of the US population. Third, people with severely impaired physical or mental health might not be able to complete the survey and thus, may have been underrepresented. Fourth, these data are self-reported and were not validated by physical or psychiatric examination. However, as pain is a subjective experience, data assessing pain can only be gathered via self-report. Fifth, as the respondent could only select one primary impairment or health problem, an analysis of other potential pain-related comorbid conditions was not possible. Additionally, as the PRAD question was referenced to the past 30 days and does not contain information on its previous course, assessment of chronic pain was not possible. Finally, because the data were cross-sectional, examining potential causal relationships between PRAD days and HRQOL measures, health behaviors, and major impairments were not possible.
The results of this study indicate that PRAD is common in the general community and strongly associated with impaired HRQOL, adverse health behaviors, and disability indices—each of which may complicate efforts to treat the underlying precipitant of pain. Furthermore, in an analysis of people with disability, those reporting that their major impairment or health problem was depression, anxiety, or emotional problems were as likely to report frequent PRAD as those reporting cardiovascular conditions. These results are particularly noteworthy because they were obtained in a population-based survey and not from patients seeking clinical evaluation or treatment, suggesting a critical need for the dissemination of targeted interventions to reduce pain. The development of public health initiatives—targeting diverse constituencies and varied diseases and conditions—could be vital in increasing recognition of both the public health and clinical importance of pain and fostering interventions that improved pain control.
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Acknowledgments |
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Human Participant Protection
This study has been approved by the Centers for Disease Control and Prevention internal review board (protocol 2988) as meeting the criteria for appropriate consent in survey research.
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Footnotes |
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Contributors
T. W. Strine originated the study, analyzed the data, and drafted the article. J. M. Hootman provided subject area expertise in the fields of pain and arthritis. D. P. Chapman provided editorial expertise. C. A. Okoro provided analytic expertise. L. S. Balluz provided eidtorial support for the project and helped in the acquisition of data.
Accepted for publication April 8, 2005.
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References |
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TOPABSTRACTINTRODUCTIONMETHODSRESULTSDISCUSSIONReferences |
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