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Smoking cigarettes is prevalent among individuals with chronic pain. Some studies indicate nicotine reduces pain and others suggest it may cause or exacerbate pain. Participants in this cross-sectional study were 151 chronic pain patients from a large, urban VA medical center. Patients were divided into 3 groups: (1) non-smokers, (2) smokers who deny using cigarettes to cope with pain, and (3) smokers who report using cigarettes to cope with pain. Patients who reported smoking as a coping strategy for chronic pain scored significantly worse compared to the other 2 groups on the majority of measures of pain-related outcome. Non-smokers and smokers who denied smoking to cope did not differ on any variable examined. After controlling for the effects of demographic and clinical factors, smoking cigarettes as a coping strategy for pain was significantly and positively associated with pain intensity (p=0.04), pain interference (p=0.005), and fear of pain (p=0.04). In addition to the assessment of general smoking status, a more specific assessment of the chronic pain patient’s reasons for smoking may be an important consideration as part of interdisciplinary pain treatment.
Individuals with chronic pain have high rates of cigarette smoking.41,50,52 Some studies estimate the odds of smoking cigarettes among chronic pain patients as more than double compared to the general population.31,34,59 The nature of the relationship between nicotine and chronic pain is complex. Smoking cigarettes may serve as a coping strategy to reduce pain, as nicotine has analgesic properties through its action on nicotinic cholinergic receptors that activate inhibitory pain pathways in the central nervous system.3 Nicotine has been demonstrated to have a direct analgesic affect in rodents.1,7 Among humans, laboratory studies have found evidence for decreased pain sensitivity among active smokers19,47 and among non-smokers who are administered nicotine prior to a painful stimuli.32,45 Smoking cigarettes may also reduce the emotional distress associated with chronic pain by shifting attention away from pain sensations.10,20
However, if nicotine use is a coping strategy for chronic pain, the positive benefits appear to be illusory. Smokers with chronic pain report higher pain intensity,9,27,30,51,56 increased rates of depression,27,28,56 greater interference with life activities due to pain,12,56,57 have increased likelihood of pain-related disability,22,51 increased opioid use,27,34 are at greater risk for suicidal ideation,14 and have poorer outcome after a pain treatment program,13,28 compared to non-smokers with chronic pain.
There are several theories regarding the relationship between cigarette smoking, prevalence of back pain, greater pain-related problems, and poorer chronic pain treatment outcomes. Several large, prospective, epidemiological studies have demonstrated an association between smoking cigarettes in adolescence and the development of low-back pain in adulthood.25,38,40,48 Smoking cigarettes is associated with intervertebral disc degeneration through vasoconstriction and increased proteolytic enzyme activity in the vertebral discs,15 leading to an increased likelihood of chronic low back injury and chronic pain. Coughing associated with persistent smoking may increase the risk of musculoskeletal injury leading to increased pain.15,16 Thus, consumption of nicotine may be a predisposing factor contributing to the development of chronic back pain following an initial injury. Also, long-term nicotine use may attenuate the effect of some opioid medications by increasing metabolism and reducing blood levels, leading to less effective analgesia and increased pain.2,58 Overall, smoking cigarettes may contribute to the evolution, exacerbation, or maintenance of chronic pain.
The purpose of this study is to explore an additional but not necessarily competitive explanation for the relationship between cigarette smoking and chronic pain. Some patients may use common non-prescribed chemicals, such as alcohol and tobacco, to reduce their pain intensity or temper the emotional distress associated with chronic pain. The term chemical coping has been used to describe the use of medications or substances in nonprescribed ways as a mechanism of coping with stress.43 Although general coping styles are strongly associated with pain-related variables,4,8,12,49 little is known about variables associated with chemical coping in particular, and how they may influence pain-related functioning. To shed light on these questions, we sought to examine the relationship between smoking cigarettes to cope with pain and pain-related variables. In this paper we explored three research questions: (1) Is there a significant proportion of chronic pain patients who consciously use cigarettes as a mechanism to cope with pain; (2) Are there significant differences on measures of pain-related outcome between chronic pain patients who use cigarettes to cope with pain and other chronic pain patients; and (3) Can the use of cigarettes to cope with pain predict meaningful aspects of pain-related functioning. Investigation of these research questions will help clarify the extent to which coping with cigarettes is associated with pain-related variables.
This study was approved by the Institutional Review Board at the Portland VA Medical Center, and all participants provided written informed consent.
This cross-sectional study was conducted at a large, urban, Department of Veterans Affairs Medical Center. Data were collected as part of a larger research study investigating the relationship between chronic pain, hepatitis C virus (HCV) infection, and substance use disorders. Participants were recruited into the study by means of posted advertisements in the hospital, letters sent to patients who had a pending appointment in primary care, announcements made in mental health classes, and referral from patients being seen in a hepatology clinic. Inclusion criteria for the study were at least 18 years of age, English-speaking, and current diagnosis of a chronic non-cancer pain condition per patient self-report (and confirmed using diagnoses from the electronic medical record). As noted, this study was part of a larger study examining chronic pain in patients with HCV; therefore, to be included patients must have a history of being tested for HCV, and both HCV positive and HCV negative patients were included. Exclusion criteria were over 70 years of age, pending litigation or disability compensation for pain, severe liver disease, current suicidal ideation, or other serious psychiatric conditions such as untreated schizophrenia or bipolar disorder.
Participants completed a packet of measures including demographic and self-report questionnaires. Pain, substance use, and psychiatric diagnoses were identified in the electronic medical record using ICD-9-CM codes recorded in the Veterans Integrated Service Network-20 Data Warehouse over a period of five years prior to the study assessment. The Data Warehouse is a centralized database that retrieves clinical data from several regional VA medical facilities and two national VA databases. The database is updated on a nightly basis and studies of the VA databases have found good reliability for diagnostic information.46
Current smoking status was assessed through a single self-report question (yes/no). Participants who endorsed this item were asked how many cigarettes they currently smoke per day. Smoking to cope with chronic pain was assessed through a yes/no response to the question: “Have you ever smoked cigarettes to help cope with pain?” We also used 1 item from the Fagerstrom Test of Nicotine Dependence23 to assess tobacco dependence: “How soon after waking do you have your first cigarette” (yes/no within 30 minutes). Individuals who smoke within 30 minutes of waking have higher general blood levels of carbon monoxide, cotinine and nicotine, and positive endorsement of this item is associated with greater nicotine dependence.24
The Multidimensional Pain Inventory (MPI)36 is a frequently used measure in research on chronic pain. Its reliability and validity has been supported in a large number of studies. The MPI includes subscales measuring subjective pain intensity (Pain Severity), interference of pain with day-to-day activities (Interference), influence of pain over the patient’s sense of control over life events (Life Control), negative emotions as a result of pain (Affective Distress), and degree of involvement in pain-related problems by the patients spouse or significant other (Support). The measure also provides subscales measuring responses to pain provided by significant others and the patient’s ability to engage in a variety of specific activities of daily living (these latter scales were excluded from the present analysis for parsimony).
The Pain Anxiety Symptoms Scale (PASS-20)39 is a brief, valid, and reliable questionnaire designed to assess the degree of anxiety and fear experienced by chronic pain patients because of pain. It includes subscales measuring cognitive, behavioral, and emotional symptoms, and a total score measuring overall pain-related anxiety and fear.
The Chronic Pain Coping Inventory (CPCI)33 is a reliable and valid self-report questionnaire designed to measure aspects of pain-related coping. It yields 7 subscale scores, each corresponding with a distinct coping strategy. Three scales are “illness-focused” (Guarding, Resting, Asking for Assistance), 3 are “wellness-focused” (Relaxation, Task Persistence, Exercise/Stretch), and 1 “other” (Seeking Social Support). The illness-focused scales are associated with less activity and more pain-related dysfunction, while the wellness-focused scales are associated with greater activity and less dysfunction.32
The Beck Depression Inventory, Second Edition (BDI-II)5 is a self-report questionnaire designed to measure depression symptoms. Higher scores indicate more severe symptoms. Studies support the validity and reliability of the BDI-II for use with chronic pain patients.18,22
The Generalized Anxiety Disorder Scale (GAD-7)54 is a reliable and valid measure that assesses for the presence of generalized anxiety disorder, with higher scores indicating more severe symptoms. Scores on the GAD-7 are also strongly correlated with measures of other anxiety disorders including posttraumatic stress disorder, panic disorder, and social anxiety disorder.37
The TimeLine Follow-Back (TLFB)53 was used to assess use of prescription opioids in the 30 days prior to the study assessment. The TLFB is a reliable, valid, and standardized tool that uses calendar prompts to track the frequency of self-reported use of different substances.25
Participants were divided into 3 groups based upon their response to the smoking items on the demographic questionnaire: (1) non-Smokers, (2) smokers who denied using cigarettes to cope with pain (Smoke No-Cope), and (3) smokers who reported using cigarettes to cope with pain (Smoke-Cope). Self-report demographic and psychiatric/substance use data were analyzed and the 3 groups were compared using analysis of variance (ANOVA) for linear variables and chi-square tests for categorical variables. A series of ANOVAs were used to analyze between group differences on measures of pain and psychiatric functioning. When significant differences were found, Tukey post-hoc tests were conducted to determine directionality.
Linear regression analyses were conducted to evaluate which variables were associated with specific dimensions of pain and pain-related functioning. Separate models were conducted to examine pain intensity, pain interference, and fear of pain. The dependent variables chosen to represent these dimensions were the Pain Severity subscale from the MPI (pain intensity), Interference subscale from the MPI (pain interference), and total score from the PASS-20 (fear of pain). Independent variables were selected for inclusion in the 3 regression models based upon their relationship with pain-related outcomes; they included age, gender, pain severity (only included for the pain interference and fear of pain models), prescription opioid use in previous 30 days, depressive symptoms, and whether participants smoked cigarettes to cope with pain. Non-Smokers and Smoke No-Cope were combined into 1 group for these analyses and compared to the Smoke-Cope group. This aggregation was done because Non-Smokers and Smoke No-Cope did not significantly differ on any demographic characteristics, pain outcome measures, or psychiatric symptom severity; and to obtain a binary variable that directly measures cigarettes to cope with pain without excluding Non-Smokers from the analysis. The Cigarettes to Cope with Pain variable was entered last into the equations to model the amount of variance in pain-related functioning associated with coping with cigarettes after controlling for the other variables. All analyses were conducted with the Statistical Package for the Social Sciences (SPSS, version 17.0). In order to control for multiple comparisons, results were considered statistically significant when p ≤ 0.01.
A total of 151 chronic non-cancer pain patients met inclusion criteria and participated in the study. Participants were predominantly male (92.1%), Caucasian (74.8%), divorced/separated (51.0%), unemployed (33.8%) or receiving disability (40.4%), and middle-aged (M = 54.2, SD = 8.8). Of those who were self-reported smokers (n = 79, 52.3%), 40 (50.6%) denied using cigarettes to cope with pain, and 39 (49.4%) reported using cigarettes to cope with pain. No significant differences were found between the 3 groups on demographic characteristics with the exception of marital status (χ2 (6) = 15.67, p = 0.02), and Non-Smokers were less likely to have a substance use disorder in the 5 years prior to the study evaluation (χ2 (2) = 6.30, p = 0.04). All participants self-reported a pain diagnosis, and review of the medical records confirmed that all had one or more pain diagnoses. The most common diagnoses in the medical record were chronic neck or joint pain (72.8%), chronic low-back (58.9%), and rheumatism/arthritis (54.3%). There were no significant differences between groups on pain diagnoses. Detailed demographic and clinical diagnostic data are displayed in Table 1.
The Smoke-Cope group did not differ from the Smoke No-Cope group on the estimated mean number of cigarettes smoked per day (12.7 versus 13.5, p = 0.63) or percentage who smoked within 30 minutes of waking (78.9% versus 59.3%, p = 0.09). Statistically significant differences were found between the 3 groups on the pain interference and support subscales of the MPI. Post-hoc testing revealed that the Smoke-Cope group scored significantly worse than the other 2 groups on both of these subscales. The Smoke No-Cope group did not differ from Non-Smokers on any subscale score of the MPI (Table 2).
The 3 groups also had statistically significant differences on 3 of the 4 subscales and Total Score of the PASS-20. Post-hoc testing revealed that the Smoke-Cope group scored significantly worse than the other 2 groups on Cognitive, Fear, and Physiological subscales, and on the Total Score. Smoke No-Cope did not differ from Non-Smokers on any subscale score of the PASS-20 (Table 2).
Statistically significant between-group differences were detected on 2 of the subscales of the CPCI. Post-hoc testing revealed that participants in the Smoke-Cope group endorsed more use of Coping Self-Statements compared to the other 2 groups, and more use of Relaxation than participants in the Smoke No-Cope group (Table 3).
There were no significant differences between the 3 groups on current symptoms of depression or anxiety, as assessed by the BDI-II and GAD-7.
Table 4 displays the results of the linear regression analyses modeling the relationship between demographic, clinical, and psychosocial variables and pain outcome variables. In the first model, which examined factors associated with pain intensity, the overall model was significant, F(1,146) = 7.68, p < 0.001, and accounted for 20% of the variance in the pain intensity. Statistically significant variables included prescription opioid use in the previous 30 days, depressive symptoms, and smoking cigarettes to cope with pain. In the second model, which examined factors associated with pain interference, the overall model was significant, F(1,145) = 36.05, p < 0.001, and accounted for 62% of the variance in pain interference. Statistically significant variables included age, pain severity, prescription opioid use in the previous 30 days, depressive symptoms, and smoking cigarettes to cope with pain. In the third model, which examined factors associated with fear of pain, the overall model was significant, F(1,145) = 12.36, p < 0.001, and accounted for 34% of the variance in fear of pain. Statistically significant variables included pain severity, depressive symptoms, and smoking cigarettes to cope with pain.
In this study we examined the associations between cigarette use and chronic pain by assessing whether smoking cigarettes as a method for coping with pain is associated with pain-related variables. We analyzed 3 groups of patients with chronic pain (non-smokers, smokers who deny using cigarettes to cope with pain, and smokers who report using cigarettes to cope with pain) and found that the purposeful use of smoking cigarettes as a coping strategy for chronic pain was associated with greater pain intensity and poorer pain-related functioning. Participants who denied smoking cigarettes as a strategy to cope with pain had similar pain-related outcomes as non-smokers. Regression analyses revealed that endorsing the use of cigarettes as a coping strategy for pain was significantly and positively associated with more pain intensity, poorer pain-related function, and more fear of pain. These associations were found even after controlling for relevant demographic characteristics, pain-related variables, depressive symptoms, and prescription opioid use. Overall, our findings suggest that the use of smoking cigarettes to cope with chronic pain is associated with a constellation of pain-related problems.
Parrott (1999)42 suggested that increased psychological and physiological pain symptoms among persistent smokers may be caused by the experience of frequent withdrawal symptoms. Therefore, poorer pain-related outcome among individuals who smoke cigarettes to cope with pain could be a reflection of greater underlying nicotine dependence. However, in our sample there were no significant differences between the 2 smoking groups in their frequency of nicotine consumption or severity of nicotine dependence. Therefore, the differences in pain-related outcome between the 2 smoking groups were likely not related to the frequency of withdrawal symptoms. It has also been suggested that differences in pain-related outcome between smokers and non-smokers could be explained by the higher prevalence of depression among smokers.27 In our sample there were no significant differences between groups on self-report measures of depression or anxiety, or in terms of clinical diagnoses. Last, it is important to note that smokers who denied using cigarettes to cope with pain did not differ from non-smokers on measures of pain-related outcome, psychiatric symptoms, or opioid use. Therefore, among the patients in our sample, as long as the smoker was not consciously using cigarettes to cope with pain, no significant relationship existed between smoking status and pain-related variables.
Significant differences were found between the two cigarette smoking groups on measures of pain-related outcome, despite the fact that no significant differences were found in opioid use or patterns of nicotine consumption. Therefore, nicotine-induced attenuation of opioid analgesia was likely not the cause of poorer pain-related outcome in our sample, as has been suggested in prior studies.2,58 The rewarding properties of nicotine may be related to the stimulation of endogenous opioids,44 and it is possible that smoking to manage stress is more prevalent among individuals who build tolerance to this effect. Although we did not measure endogenous opioids in this study, the lack of significant differences in prescription opioid use between all three groups (both smoking and non-smoking) suggests that, in our sample, opioid-related variables may not be related to smoking status or coping with cigarettes. However, a systematic investigation controlling for opioid dose and endogenous opioid levels is needed to confirm this supposition.
The use of nicotine to cope with a distressing state has been studied and described in various terms in the scientific literature. Individuals with depression, anxiety, and particularly attention-deficit hyperactivity disorder may smoke cigarettes as a means of symptom reduction or stabilization, e.g. “self-medication.”17 A longitudinal study of 662 adolescents attempted to directly investigate self-medication of depression with cigarettes through use of a self-medication scale.6 The study found that smokers with higher self-medication scores had increased depression symptom severity, but more symptom stability, as compared to both non-smokers and smokers with low self-medication scores. The authors theorized that self-medication with cigarettes may be a trade-off between overall increased depression severity but greater long-term symptom stability. The findings of this study have similarities with the current study, and although we were not able to measure variation in pain severity over time, it is possible that smoking cigarettes may produce a similar trade-off when used to self-medicate symptoms of chronic pain.
Analyses of the different coping styles between the 3 groups provided mixed results. Although our findings suggest that smoking cigarettes to cope with pain is associated with poorer pain-related outcomes, we also found that smokers who used cigarettes to cope with pain endorsed higher scores on CPCI wellness-focused subscales assessing the use of relaxation and coping self-statements. It is possible that individuals who smoke cigarettes to help cope with chronic pain view smoking cigarettes as an active, purposeful coping mechanism that can provide relaxation and decrease pain-related anxiety. However, in the context of our study findings, this may be a misconception, or at least a fleeting phenomenon.
Individuals who are more pre-occupied with pain may have been more likely to report using cigarettes to cope with pain, and also may have scored worse on the pain measures. Therefore, the lower scores on pain-related function in the smoke-cope group may be less related to the conscious use of cigarettes to cope with pain, and more related to the mediating effect of preoccupation with pain. Although a causal relationship cannot be proven using our study design, smoking cigarettes as a mechanism to cope with pain appears to be associated with greater pain intensity and impairment. Longitudinal research is needed to clarify the interrelationships between cigarette use, coping, and pain-related function.
There are several limitations to this study. The cross-sectional design prevented us from determining causality. We used a single item self-report question to assess coping with pain with cigarettes, which has face validity, but may be only a gross proxy. To follow up on our results, studies should use more comprehensive self-report measures and biological markers of smoking status and behaviors (e.g., expired carbon monoxide). Studies that measure biological variables, such as endogenous opioid levels, may also help determine whether membership in a certain smoking group is associated with a particular chronic pain-smoking phenotype. Also, rather than relying on self-report measures of pain intensity, it may be valuable to measure this variable via quantitative sensory testing. Other limitations relate to the generalizability of our sample. All participants were veterans recruited from a single VA medical center, were predominantly male, middle to older age, and overrepresented by individuals who have the hepatitis C virus and a history of psychiatric and substance use disorders. Our sample also had average pain severity scores in the mild-to-moderate range, so the results may not generalize to those with severe pain.
Despite these limitations, the results of this study may have important clinical implications. Coping strategies for pain are a common focus of interdisciplinary pain treatment programs. However, it is doubtful if much attention is given to the use of smoking cigarettes as a coping strategy for pain and how this may be associated with pain-related function. Our results suggest that smoking cigarettes to cope with pain is associated with poorer pain-related outcome. Therefore, as part of a multidisciplinary pain treatment approach it may be important to assess if a patient is using cigarettes as a coping strategy for pain (in addition to assessing smoking status more generally). Patients who answer in the affirmative may benefit from interventions focused on reducing the use of cigarettes as a coping mechanism and increasing the use of alternative positive, effortful, self-initiated coping strategies (e.g., cognitive self-talk, exercise, relaxation).
This paper describes the relationship between smoking cigarettes as a mechanism to cope with chronic pain and pain-related outcome. Understanding this relationship may illuminate the broader relationship between smoking and chronic pain and provide new directions for effective interdisciplinary pain treatment.
This manuscript is the result of work supported with resources and the use of facilities at the Portland VA Medical Center. This study was funded by grant K23DA023467 from the National Institute on Drug Abuse, awarded to Dr. Morasco. Dr. Turk has received research support from Endo, Johnson & Johnson, Philips Respironics, and the National Institutes of Health, and consulting fees from Eli Lilly, Empi, Johnson & Johnson, Pfizer, Philips Respironics, and SK LifeScience. He is also a Special Government Employee of the U.S. Food and Drug Administration.
We appreciate the assistance of Lynsey Lewis, Renee Cavanagh, and Aysha Crain with data collection. Dr. Patterson is now affiliated with the National Center for Telehealth and Technology (T2). The content of this manuscript is solely the responsibility of the authors and does not necessarily represent the official views of the Department of Veterans Affairs or the National Institutes of Health.
No other author reports having any potential conflict of interest with this study.
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