Addictive Behaviors, Vol. 16, pp. 103-l 10, 1991 Printed in the USA. All rights reserved.
Copyright
0306-4603/91 $3.00 + .OO Q 1991 Pergamon Press plc
THE RELATIONSHIP BETWEEN CIGARETTE SMOKING CHRONIC LOW BACK PAIN
AND
ROBERT N. JAMISON Brigham and Women’s Hospital
BARBARA
A. STETSON Vanderbilt
and WINSTON
University
C.V. PARRIS
Medical Center
Abstract - This study investigated the extent to which habitual cigarette smoking relates to physical and psychological indices of chronic pain. From a review of patient records, 54% of back pain patients referred for treatment of their pain admitted to smoking cigarettes. Response from a smoking questionnaire showed that 57% of the patients who smoked reported having a need to smoke when they were in pain. Most patients (91%). however, believed that smoking had no effect on their pain intensity. When smoking and nonsmoking back pain patients were compared, the smokers showed significantly higher levels of emotional distress, they tended to remain inactive, and they relied on medication more often than the nonsmoking patients. The results further suggest that pain patients are at risk for increasing smoking behavior when they are experiencing periods of heightened pain intensity.
Chronic pain is a major health problem in our society. The detrimental effects on the lives of pain patients are widespread. Frequently, individuals with chronic pain experience reduced capacity to earn a living, show marked avoidance of physical and pleasurable activity, have family conflicts, and face physical limitations (Philips, 1988). Increasing evidence has been presented for the efficacy of behavioral approaches designed to promote adaptive functioning in chronic pain patients (Gottlieb, Koller, and Allperson, 1982; Turk and Genest, 1979). Despite recent gains in the behavioral management of chronic pain, little emphasis has been placed on the health risk factors to these patients that may often be associated with their conditions. Apart from increased weight gain and dependence on medication, chronic pain patients may be prone toward cigarette smoking because of its supposed relief from anxiety and possible relief from pain (Pomerleau, Turk, and Fertig, 1984; Silverstein, 1982). Unfortunately, little is known about how pain influences smoking frequency or how smoking affects the long-term physiological and psychological functioning of persons with chronic pain. Several surveys have reported a relationship between smoking and chronic pain. In a general population survey of behavioral health risk factors in the United States, 30% of the population were found to be current smokers (Nuprin, 1985). It is estimated that the percentage of smokers in the general population has continued to decrease since that time. Persons who reported having pain showed a higher rate of smoking. Of those individuals who reported having ‘ ‘unbearable pain, ’ ’ 37% smoked, while 27% of persons who reported having “slight pain” smoked. As pain severity increased, there was a tendency to exercise less and smoke more (Nuprin, 1985). An epidemiological study of a large sample of Swedish men found a correlation between back pain and smoking. Pain and smoking frequency were
The authors acknowledge with gratitude the assistance of Karen A. Lindsey and Kenneth H. Joel. Requests for reprints should be sent to Robert N. Jamison, Ph.D., Pain Treatment Service, Brigham Women’s Hospital, 75 Francis St., Boston, MA 02115. 103
and
104
ROBERT N. JAMISON
et al
also associated with worry, tension, fatigue, and perception of stress (Biering-Sorensen and Thomsen, 1986). Researchers have proposed mechanisms by which smoking may be a risk factor for both the onset and perpetuation of chronic pain (Benowitz, 1988; Frymoyer, Pope, Clemens, Wilder, MacPhearson, & Ashikaga, 1983). Cigarette smoking may contribute to a chronic cough that, in turn, may lead to increased mechanical stress including higher pressure on the vertebral disks. Smoking may also reduce vertebral-body blood flow that might adversely affect discal functioning as well as making the disk more susceptible to mechanical difficulties (Frymoyer et al, 1983). Further, a correlation has been reported between smoking and vertebral osteoparosis (Svensson, Vedin, Wilhelmsson, & Anderson, 1983). Unfortunately, prospective evaluations of these theories have not been conducted. Controlled studies of the physiological effects of smoking do provide evidence that nicotine may produce significant autonomic arousal (Benowitz, 1988; Hill & Wynder. 1974). The smoking of one or two cigarettes or administration of an equivalent amount of nicotine by other means typically causes an increase in heart rate, increased blood pressure, and adrenalcortical compounds (Hill & Wynder, 1974). Smoking has been found to produce vasoconstriction (Herxheimer, Griffiths, Hamilton, & Wakefield, 1967; Simon & Iglauer, 1967) and stimulation of beta-endorphin release in circulating plasma (Pomerleau, 1986). Also, smoking accelerates the metabolism of many drugs, and the efficacy of sedatives and analgesics appear to be reduced in cigarette smokers (Internal Medicine Alert, 1988). Several laboratory studies have examined the relationship between smoking and pain tolerance (Friedman, Horvath & Meares, 1974; Nesbitt, 1973; Seltzer, Friedman, Siegelaub, & Collen, 1974; Sult & Moss, 1986). The bulk of the evidence of these studies would suggest that smoking can produce relief from pain and anxiety, although the results have been inconclusive. Further studies have attempted to examine the motives behind smoking habits in the general population. Smoking has been seen as a coping strategy to promote reductions in affect or to achieve relaxation (Ikard, Green, & Horn, 1969; Ikard & Thompkins, 1973; Revell, Warburton & Wesnes, 1985). Unfortunately, research efforts in examining how smoking modulates pain perception in chronic pain patients have, for the most part, been neglected. The aim of the present study is to revaluate the perceived effects of smoking on chronic pain patients. Four primary questions are raised: (1) How does the prevalence of smoking among chronic pain patients compare with that of the general population? (2) How do pain patients perceive that smoking affects their pain? (3) Do pain patients who smoke feel an increased need to smoke during episodes of increased pain intensity? (4) Are there differences in the psychosocial functioning of smoking and nonsmoking chronic pain patients? METHODS
Preliminary data collection In order to determine the smoking frequency of chronic back pain patients, a post hoc review of past patient information from the Vanderbilt University Pain Control Center was conducted. Charts of 250 low back pain patients who had attended the chronic pain center for treatment of their back pain were randomly sampled and reviewed. All patients had been referred to the multidisciplinary pain center between 1986 and 1988 and had answered the following question as part of their initial evaluation: “Do you smoke cigarettes?” Of the 250 charts reviewed, 136 of the patients (54.4%) answered “yes.” This compares with a published survey conducted by the Centers for Disease Control of the U.S. Department of Health and Human Services in 1986, in which 28.0% (2 2.4) of responders from Tennessee (n = 1,779) said that they were current smokers (U.S. Department of Health and Human
Smoking and chronic pain
Services, 1987). The reported national for that year was 26.5% (2 1.1).
105
average for current cigarette smoking among adults
Subjects
Two hundred and nine chronic pain patients who were referred to the Vanderbilt Pain Control Center, which is predominantly an outpatient university hospital-based pain program, participated in the next phase of this study. All patients were being treated for chronic low back pain and were randomly selected for this study by order of their admission. The patients ranged in age from 18 to 79 (mean = 43.9; SD = 13.5), 48.9% of the patients were female and 88.4% were Caucasian. They averaged 11.8 years of education (SD = 2.7) and 69.0% were married. Thirty-three percent reported working at the time of the assessment, while 50.5% reported being out of work. Seventeen percent of the patients were receiving worker’s compensation and 12.1% had litigation pending related to their pain. The pain intensity ratings ranged from 40 to 100 on a O-100 scale (mean = 86.3; SD = 15.3) and pain duration from 4 to 744 months (mean = 57.4; SD = 91.1). Procedure
Upon admission to the pain center, the patients completed a pain evaluation questionnaire that covered demographic information, pain ratings, psychosocial data, physical changes, and perceived impact of pain on daily activities. The patients were also asked to complete an XL-90-R (Derogatis, 1977), which is a 90-item checklist commonly used with medical populations to assess emotional distress. Physicians then performed a comprehensive intake interview using a structured format and addressing such issues as pain history, social history, pain descriptions, pain onset, and medication usage. In addition, all patients underwent a brief physical and neurological examination prior to treatment. Initially, 134 back pain patients who confirmed that they were cigarette smokers were asked to complete a lo-item smoking questionnaire. Eight of the items on the questionnaire were taken from a previously published questionnaire (Orleans & Shipley, 1982), and two additional items were added concerning smoking and pain. Of 134 patients, 19 patients admitted to smoking less than 15 cigarettes per day and, based on their responses, did not appear to be regular smokers. For purposes of this study, these 19 patients were excluded from the analyses. The remaining 115 low back pain patients who reported smoking more than 15 cigarettes per day were compared with 75 nonsmoking low back pain patients on the assessment variables. RESULTS
The results of the smoking questionnaire for low back pain patients are presented in Table 1. Overall, most patients who smoked showed evidence of being heavy smokers. Most of these patients began smoking during their teenage years, they smoked an average of 1% packs of cigarettes per day, 90% of the patients reported smoking from two-thirds to all of the cigarette, and they almost always inhaled while they smoked. Over 40% of the patients reported smoking a cigarette as soon as they woke up in the morning, and most of the patients had never tried to quit smoking for longer than a month. Only 9% of the patients felt that smoking directly affected their pain intensity; however, 57% stated that they needed to smoke while in pain. Differences on a number of pain variables between smoking and nonsmoking low back pain patients are presented in Table 2. No significant differences were found between groups on sex, work status, pain intensity ratings, or the extent to which pain interfered with their activity. Smokers were found to be significantly younger and less well educated. They reported having sleep disturbances and relied on sleeping medication. The smokers reported
IOh
ROBERT N. JAMISON
Table 1. Results of the Smoking Questionnaire
I.
et al.
for low back pain patient\
who smoke (n = 134)
How old were you when you began to smoke regularly’?
x = 1x.7 (Range 540
Exactly what brand do you smoke?
73. I % menthol 3X.X% Long\ 90.3% Filters
In an average day. how many cigarettes do you usually smoke’?
x = 27.2 (Range I-100)
How many cigarettes would you estimate you smoked per day over the past week’?
x = 28.X
On the average. how much of a cigarette do you smoke’?
’ 1 = 9.7% = 21 = 13.3% All = 47.0%
h.
Do you inhale?
Sometime?, = 2.5.X% Alway‘; = 71.2%
7.
How soon after you wake up do you smoke your first cigarette?
X = 29.4 min “Immediately” 11.0%
8.
How does smoking affect your pain’?
M&es pain better Makes pain worse No effect Don’t k’now
9.
Do you feel a need to smoke while you are in pain?
Ye> No
10.
What is the longest time that you have quit smoking?
x = 17.5 months (Range 0 days-l 5 years)
2.
(Ranye
I
I-IOO)
6.0% 3.0% 57.5% 33.6%
56.7Fic 33.3%
that walking tended to make their pain worse, and they endorsed having significantly higher levels of emotional distress based on scores from the SCL-90. A stepwise discriminant function analysis was used to further examine the 10 variables from Table 2 in order to determine which variables were best able to predict differences
Table 2. Comparisons
between smoking and nonsmoking
Variables Age (years) Education (years) Date of pain onset (months) Work-related injury (‘% yes) Walking makes pain worse (% yes) Trouble falling asleep” Takes sleeping medication” Sexual activity (B unsatisfactory) Have you been depressedh SCL-90 global scale (r-scores) “I = “never”; 5 = “every night.” hl = “not at all”; 5 = “extremely.” *p < 0.05. **p < 0.02. ***p < 0.001.
Smokers (n = I 15) 42.0 11.2 68.1 51.7 47.1 4.27 3.10 71.2 3.22 66.8
low back pam patients on pain variables Nonsmoker5
(n = 75)
17. I 12.7 41 .O 20.8 31.3 3.63 2.12 56.5 2.x3 63.3
r 2.43* 3.82*** 2.22* 3.32** 7.1x* 3.37** 2.55* 2.22* 1.9x* 2.43*
Smoking and chronic pain
Table 3. Correlations
107
between the need to smoke when in pain and psychosocial
Tense
Irritable
Nervous”
Anxious”
.24*
.21*
.27**
.25**
No desire for social activity
No desire for recreation
Uses narcotics
Stays in bed
.31**
.27*’
.20*
Need to smoke
Need to smoke
.22*
variables Unsatisfactory social life
.23* Pain is constant
No. of pain descriptors
.23*
.20*
“Physician rated. *p < .05. **p < .Ol.
between the smoking and nonsmoking back pain patients. Eight variables were found to be most useful in discriminating between patient groups. These included (1) sleep disturbances, (2) walking makes pain worse, (3) work-related injuries, (4) age, (5) formal education, (6) duration of pain, (7) relying on sleeping medication, and (8) emotional distress. Sixty-seven percent of the cases were correctly classified into either the smoking or nonsmoking groups for a combined Wilks’ lambda of .72 and a canonical correlation of .53. A comparison was made between smokers who reported needing to smoke when they were in great pain (n = 72) and smokers who reported not needing to smoke when in pain (n = 43) on a number of psychosocial variables. Correlational results are presented in Table 3. Patients who stated that they needed to smoke while in pain showed higher self-rated and physician-rated emotionality and reported being dissatisfied with their social lives. They tended to have little desire for social and recreational activity. They relied on narcotic pain medication, and they were often confined to bed. They described their pain as constant, and they tended to use more pain descriptors when describing their pain, Thus, those patients who showed high emotionality and who were generally inactive were at greater risk for smoking when they were in significant pain. DISCUSSION
There are a number of findings from the results of this study. First, a greater percentage of referrals to a multidisciplinary pain center were found to smoke compared with the general population. Most chronic pain patients who did smoke were heavy smokers and admitted to being dependent on cigarettes. Second, chronic pain patients did not believe that smoking cigarettes increased (or decreased) their subjective pain intensity. The consistent reaction from almost all of the patients (9 1%) was that cigarette smoking either had no effect on their pain, or they were uncertain of its effect. Third, the majority of pain patients who smoked reported an increased need to smoke during those periods when their pain was most severe. Thus, pain patients were found to be at risk for smoking, especially during times when their pain had increased. Also, these patients showed a positive relationship between having a need to smoke and showing considerable emotionality. Finally, differences were found between smokers and nonsmokers on a number of psychosocial variables. Overall, smokers tended to present more maladaptive pain behaviors compared with nonsmokers. These included decreased activity, reliance on medication, and expression of emotional distress. It is unclear why only a few of the patients in this study felt that smoking influenced their
108
ROBERT N. JAMISON
et al
pain, since past studies found that nicotine acted to decrease pain intensity. There are a number of possible explanations. First, nicotine may have less of an effect in alleviating chronic pain versus acute pain. Most of the published studies that demonstrated an increase in pain tolerance after ingesting nicotine examined patients’ reactions to experimentally induced acute pain. Quite possibly, chronic pain patients respond differently to the physiological effects of nicotine. Second, the fact that one-third of the responders did not know whether smoking affected their pain or not may reflect the paradoxical possibilities of smoking on pain. This is in keeping with Gilbert’s (1979) finding that nicotine increases antonomic arousal yet reduces self-reported anxiety. The affects of nicotine on pain is not direct. Nicotine activates increasing concentrations of norepinephrine and epinephrine in the blood while also possibly increasing a release of beta-dorphin that may mediate a decrease in pain perception. A third possibility is that nicotine may increase arousal while also decreasing the attention the individual gives to painful symptoms or decreasing the need to respond to pain. Further studies are needed to help substantiate these hypotheses. It is also unclear from these results why chronic pain patients who participated in this study and who smoked tended to report an increase in smoking behavior when their pain intensity increased. The pain patients gave a number of anecdotal reasons to account for their increased frequency of cigarette smoking. These included boredom, a need for distraction, anxiety, nervousness, depression, anger, frustration, and enjoyment from the effects of inhaling the smoke. It is difficult, however, to separate the differences between the pharmacological efficacy and the reinforcing efficacy of smoking on pain. A number of studies examining the reinforcing effects of drugs on behavior (Rose, Ananda, & Jarvik, 1983) have pointed out that there are simultaneously both positive and aversive reactions with ingesting any drug. It has been shown in animal studies using cocaine that the act of taking any drug can be very reinforcing (Spealman, 1979). Of particular relevance to this study is the notion that when reinforcers in an individual’s environment are removed, the individual seeks to maintain stable rates of reinforcers (Carroll & Meisch, 1984). This leads to an interesting notion regarding smoking behavior in chronic pain patients. When these patients are deprived of social reinforcers (e.g., work, social, and recreational activity, etc.), they make up for their loss of stimulus by increasing other reinforcing behaviors such as eating and smoking. Thus, social deprivation and lack of positive experiences may play a part in contributing to increased cigarette smoking in chronic pain patients. Anecdotal reports suggest that pain patients tend to overeat and crave sweets, and it has been determined that obese sedentary adults tend to overeat in response to emotions and somatic complaints (Schlundt, Sbrocco, & Bell, 1989). This has implications for designing interventions for those patients who are disabled from their pain and who express an interest in quitting smoking. Efforts should be made to examine the present reinforcers and substitute other behaviors that might help to distract the patient from smoking. One limitation of the results of this study is that the data are correlational in nature. Thus, it can not be determined whether smokers tend to be emotional and express more pain behavior or whether the pain condition actively contributes to the smoking behavior. The data also are based on self-report items, and there was no measurement of the physiological component of smoking and its effect on chronic pain. Another potential problem pertains to the subject population. The majority of the patients in this study had not completed high school, and many came from a lower socioeconomic group than might possibly be found in other chronic pain populations. This may account, in part, for the higher rate of cigarette smokers. It is doubtful, however, that the 54% incidence of cigarette smoking was due solely to demographic factors alone. Replicating this study with other groups of pain patients may prove beneficial.
Smoking and
chronic pain
109
These results point to a need for further study of the incidence of cigarette smoking in chronic pain patients. Both behavioral and physiological influences of smoking need to be examined. This study failed to address whether smoking frequency significantly increased following the onset of the pain. Patients with other types of pain (e.g., headaches, abdominal pain) were not included. Also, further information is needed in understanding the reinforcing effects of cigarette smoking for pain patients who are not referred for treatment of their pain. The results of this initial investigation suggest, however, that chronic pain patients may be at risk for increasing their smoking behavior and that increased pain intensity and emotional distress factors are related to a need to smoke in this select population of pain patients.
REFERENCES N.L. (1988). Pharmacologic aspects of cigarette smoking and nicotine addiction. New England Journal 319, 1318-1330. Biering-Sorensen, F., & Thomsen, C. (1986). Medical, social and occupational history as risk indicators for low-back trouble in a general population. Spine, 11, 720-725. Carroll, M.E., & Meisch, R.A. (1984). Increased drug-reinforced behavior due to food deprivation. In L. Iversen (Ed.), Advances in behavioral pharmacology (pp. 47-88). New York: Academic Press. Derogatis, L. (1977). SCL-90-R (Revised Version) Administration, Scoring and Procedure Manual. Baltimore: Johns Hopkins University School of Medicine. Friedman, J., Horvath, T., & Meares, R. (1974). Tobacco smoking as stimulus barrier. Nature, 248, 455456. Frymoyer, J. W., Pope, M.H., Clemens, J.H., Wilder, D.G., MacPhearson, B., & Ashikaga, T. (1983). Risk factors in low-back pain: An epidemiological survey. Journal of Bone and Joint Surgery, 65, 213-218. Gilbert, D.G. (1979). Paradoxical tranquilizing and emotion reducing effects of nicotine. Psychological Bullerin, 86, 643-66 1. Gottlieb, H.J., Keller, R., & Allperson,B.L. (1982). Low back pain comprehensive rehabilitation program: A follow-up study. Archives of Physical Medicine and Rehabilitation, 65, 458-461. Herxheimer, A., Griffiths, R.L., Hamilton, B., & Wakefield, M. (1967). Circulatory effects of nicotine aerosol inhalations and cigarette smoking in man. Lancer, ii,754-755. Hill, P., & Wynder, E.L. (1974). Smoking and cardiovascular disease: Effect of nicotine on the serum epinephrine and corticoids. American Heart Journal, 87, 491-496. Ikard, F.F., Green, D.E. & Horn, D. (1969). A scale to differentiate between types of smoking as related to the management of affect. International Journal of the Addictions, 4, 649-659. Ikard, F.F., & Tompkins, S. (1973). The experience of affect as a determinant of smoking behavior: A series of validity studies. Journal of Abnormal Psychology, 81, 172-181. Infernal Medicine Alerr (1988). 10, 87-88. Nesbitt, P.D. (1973). Smoking, physiological arousal, and emotional response. Journal of Personaliry and Social Benowitz,
ofMedicine,
Psychology, 25, 137-144. Nuprin Pain Report (1985). New York: Louis Harris & Associates,
Inc., pp. 161-162. Orleans, C.S., & Shipley, R.A. (1982). Assessment in smoking cessation research: some practical guidelines. In F.J. Keefe & J.A. Blumenthal (Eds.), Assessmenr strafegies in behavioral medicine. New York: Grune & Stratton. Philips, H.C. (1988). The psychological management of chronic paint A treatment manual. New York: Springer. Pomerleau, O.F. (1986). Nicotine as a psychoactive drug: Anxiety and pain reduction. Psychopharmacology Bulletin, 22, 865-869.
Pomerleau,
O., Turk, D.C., & Fertig. J.B. (1984). The effects of cigarette smoking on pain and anxiety. Addicrive
Behaviors,
9, 265-271.
Rose, J.E., Ananda, S., & Jarvik, M.E. (1983). Cigarette smoking during anxiety-provoking and monotonous tasks. Addictive Behaviors, 8, 353-359. Revell, A.D., Warburton, D.M., & Wesnes, K. (1985). Smoking as a coping strategy. Addicfive Behaviors, 10, 209-224. Schlundt, D.G., Sbrocco, T., & Bell, C. (1989). Identification of high risk situations in a behavioral weight loss program: application of the relapse prevention model. International Journal of Obesity, 13, 223-234. Seltzer, C., Friedman, G., Siegelaub, A., & Cohen, M. (1974). Smoking habits and pain tolerance. Archives of Environmental Health, 29, 170-172. Silverstein, B. (1982). Cigarette smoking, nicotine addiction, and relaxation. Journal of Personality and Social Psychology,
42, 946-950.
Simon, D.L., & Iglauer, A. (1967). The acute effect of chewing tobacco and smoking in habitual users. Annals of the New York Academy of Sciences, 142, 119-132. Spcalman, R.D. (1979). Behavior maintained by termination of a schedule of self-administered cocaine. Science, 204, 1231-1233.
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Suit, S.C., & Moss, R.A. (1986). The effects of cigarette smoking on the perception of electrical stimulation and cold pressor pain. Addictive Behaviors. 11, 44745 1. Svensson, H.O., Vedin. A., Wilhelmsson. C.. & Anderson, G.B.J. (1983). Low-back pain in relation to other diseases and cardiovascular risk factors. Spine, 8, 277-285. Turk, D.C. & Genest, M. (1979). Regulation of pain: The application and cognitive and behavioral techniques for prevention and remediation. In P. Kendall & S. Hollon (Eds.), Cognirive hehnviornl intervmrion.s: Theoq, research and procedures (pp 287-318). New York: Academic Press. U.S. Department of Health and Human Services (1987). Morbidiy nnd Murrrtliy Weekly Report, Pub. No. 87-8017, 36,(16).
Copyright
0306-4603/91 $3.00 + .OO Q 1991 Pergamon Press plc
THE RELATIONSHIP BETWEEN CIGARETTE SMOKING CHRONIC LOW BACK PAIN
AND
ROBERT N. JAMISON Brigham and Women’s Hospital
BARBARA
A. STETSON Vanderbilt
and WINSTON
University
C.V. PARRIS
Medical Center
Abstract - This study investigated the extent to which habitual cigarette smoking relates to physical and psychological indices of chronic pain. From a review of patient records, 54% of back pain patients referred for treatment of their pain admitted to smoking cigarettes. Response from a smoking questionnaire showed that 57% of the patients who smoked reported having a need to smoke when they were in pain. Most patients (91%). however, believed that smoking had no effect on their pain intensity. When smoking and nonsmoking back pain patients were compared, the smokers showed significantly higher levels of emotional distress, they tended to remain inactive, and they relied on medication more often than the nonsmoking patients. The results further suggest that pain patients are at risk for increasing smoking behavior when they are experiencing periods of heightened pain intensity.
Chronic pain is a major health problem in our society. The detrimental effects on the lives of pain patients are widespread. Frequently, individuals with chronic pain experience reduced capacity to earn a living, show marked avoidance of physical and pleasurable activity, have family conflicts, and face physical limitations (Philips, 1988). Increasing evidence has been presented for the efficacy of behavioral approaches designed to promote adaptive functioning in chronic pain patients (Gottlieb, Koller, and Allperson, 1982; Turk and Genest, 1979). Despite recent gains in the behavioral management of chronic pain, little emphasis has been placed on the health risk factors to these patients that may often be associated with their conditions. Apart from increased weight gain and dependence on medication, chronic pain patients may be prone toward cigarette smoking because of its supposed relief from anxiety and possible relief from pain (Pomerleau, Turk, and Fertig, 1984; Silverstein, 1982). Unfortunately, little is known about how pain influences smoking frequency or how smoking affects the long-term physiological and psychological functioning of persons with chronic pain. Several surveys have reported a relationship between smoking and chronic pain. In a general population survey of behavioral health risk factors in the United States, 30% of the population were found to be current smokers (Nuprin, 1985). It is estimated that the percentage of smokers in the general population has continued to decrease since that time. Persons who reported having pain showed a higher rate of smoking. Of those individuals who reported having ‘ ‘unbearable pain, ’ ’ 37% smoked, while 27% of persons who reported having “slight pain” smoked. As pain severity increased, there was a tendency to exercise less and smoke more (Nuprin, 1985). An epidemiological study of a large sample of Swedish men found a correlation between back pain and smoking. Pain and smoking frequency were
The authors acknowledge with gratitude the assistance of Karen A. Lindsey and Kenneth H. Joel. Requests for reprints should be sent to Robert N. Jamison, Ph.D., Pain Treatment Service, Brigham Women’s Hospital, 75 Francis St., Boston, MA 02115. 103
and
104
ROBERT N. JAMISON
et al
also associated with worry, tension, fatigue, and perception of stress (Biering-Sorensen and Thomsen, 1986). Researchers have proposed mechanisms by which smoking may be a risk factor for both the onset and perpetuation of chronic pain (Benowitz, 1988; Frymoyer, Pope, Clemens, Wilder, MacPhearson, & Ashikaga, 1983). Cigarette smoking may contribute to a chronic cough that, in turn, may lead to increased mechanical stress including higher pressure on the vertebral disks. Smoking may also reduce vertebral-body blood flow that might adversely affect discal functioning as well as making the disk more susceptible to mechanical difficulties (Frymoyer et al, 1983). Further, a correlation has been reported between smoking and vertebral osteoparosis (Svensson, Vedin, Wilhelmsson, & Anderson, 1983). Unfortunately, prospective evaluations of these theories have not been conducted. Controlled studies of the physiological effects of smoking do provide evidence that nicotine may produce significant autonomic arousal (Benowitz, 1988; Hill & Wynder. 1974). The smoking of one or two cigarettes or administration of an equivalent amount of nicotine by other means typically causes an increase in heart rate, increased blood pressure, and adrenalcortical compounds (Hill & Wynder, 1974). Smoking has been found to produce vasoconstriction (Herxheimer, Griffiths, Hamilton, & Wakefield, 1967; Simon & Iglauer, 1967) and stimulation of beta-endorphin release in circulating plasma (Pomerleau, 1986). Also, smoking accelerates the metabolism of many drugs, and the efficacy of sedatives and analgesics appear to be reduced in cigarette smokers (Internal Medicine Alert, 1988). Several laboratory studies have examined the relationship between smoking and pain tolerance (Friedman, Horvath & Meares, 1974; Nesbitt, 1973; Seltzer, Friedman, Siegelaub, & Collen, 1974; Sult & Moss, 1986). The bulk of the evidence of these studies would suggest that smoking can produce relief from pain and anxiety, although the results have been inconclusive. Further studies have attempted to examine the motives behind smoking habits in the general population. Smoking has been seen as a coping strategy to promote reductions in affect or to achieve relaxation (Ikard, Green, & Horn, 1969; Ikard & Thompkins, 1973; Revell, Warburton & Wesnes, 1985). Unfortunately, research efforts in examining how smoking modulates pain perception in chronic pain patients have, for the most part, been neglected. The aim of the present study is to revaluate the perceived effects of smoking on chronic pain patients. Four primary questions are raised: (1) How does the prevalence of smoking among chronic pain patients compare with that of the general population? (2) How do pain patients perceive that smoking affects their pain? (3) Do pain patients who smoke feel an increased need to smoke during episodes of increased pain intensity? (4) Are there differences in the psychosocial functioning of smoking and nonsmoking chronic pain patients? METHODS
Preliminary data collection In order to determine the smoking frequency of chronic back pain patients, a post hoc review of past patient information from the Vanderbilt University Pain Control Center was conducted. Charts of 250 low back pain patients who had attended the chronic pain center for treatment of their back pain were randomly sampled and reviewed. All patients had been referred to the multidisciplinary pain center between 1986 and 1988 and had answered the following question as part of their initial evaluation: “Do you smoke cigarettes?” Of the 250 charts reviewed, 136 of the patients (54.4%) answered “yes.” This compares with a published survey conducted by the Centers for Disease Control of the U.S. Department of Health and Human Services in 1986, in which 28.0% (2 2.4) of responders from Tennessee (n = 1,779) said that they were current smokers (U.S. Department of Health and Human
Smoking and chronic pain
Services, 1987). The reported national for that year was 26.5% (2 1.1).
105
average for current cigarette smoking among adults
Subjects
Two hundred and nine chronic pain patients who were referred to the Vanderbilt Pain Control Center, which is predominantly an outpatient university hospital-based pain program, participated in the next phase of this study. All patients were being treated for chronic low back pain and were randomly selected for this study by order of their admission. The patients ranged in age from 18 to 79 (mean = 43.9; SD = 13.5), 48.9% of the patients were female and 88.4% were Caucasian. They averaged 11.8 years of education (SD = 2.7) and 69.0% were married. Thirty-three percent reported working at the time of the assessment, while 50.5% reported being out of work. Seventeen percent of the patients were receiving worker’s compensation and 12.1% had litigation pending related to their pain. The pain intensity ratings ranged from 40 to 100 on a O-100 scale (mean = 86.3; SD = 15.3) and pain duration from 4 to 744 months (mean = 57.4; SD = 91.1). Procedure
Upon admission to the pain center, the patients completed a pain evaluation questionnaire that covered demographic information, pain ratings, psychosocial data, physical changes, and perceived impact of pain on daily activities. The patients were also asked to complete an XL-90-R (Derogatis, 1977), which is a 90-item checklist commonly used with medical populations to assess emotional distress. Physicians then performed a comprehensive intake interview using a structured format and addressing such issues as pain history, social history, pain descriptions, pain onset, and medication usage. In addition, all patients underwent a brief physical and neurological examination prior to treatment. Initially, 134 back pain patients who confirmed that they were cigarette smokers were asked to complete a lo-item smoking questionnaire. Eight of the items on the questionnaire were taken from a previously published questionnaire (Orleans & Shipley, 1982), and two additional items were added concerning smoking and pain. Of 134 patients, 19 patients admitted to smoking less than 15 cigarettes per day and, based on their responses, did not appear to be regular smokers. For purposes of this study, these 19 patients were excluded from the analyses. The remaining 115 low back pain patients who reported smoking more than 15 cigarettes per day were compared with 75 nonsmoking low back pain patients on the assessment variables. RESULTS
The results of the smoking questionnaire for low back pain patients are presented in Table 1. Overall, most patients who smoked showed evidence of being heavy smokers. Most of these patients began smoking during their teenage years, they smoked an average of 1% packs of cigarettes per day, 90% of the patients reported smoking from two-thirds to all of the cigarette, and they almost always inhaled while they smoked. Over 40% of the patients reported smoking a cigarette as soon as they woke up in the morning, and most of the patients had never tried to quit smoking for longer than a month. Only 9% of the patients felt that smoking directly affected their pain intensity; however, 57% stated that they needed to smoke while in pain. Differences on a number of pain variables between smoking and nonsmoking low back pain patients are presented in Table 2. No significant differences were found between groups on sex, work status, pain intensity ratings, or the extent to which pain interfered with their activity. Smokers were found to be significantly younger and less well educated. They reported having sleep disturbances and relied on sleeping medication. The smokers reported
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ROBERT N. JAMISON
Table 1. Results of the Smoking Questionnaire
I.
et al.
for low back pain patient\
who smoke (n = 134)
How old were you when you began to smoke regularly’?
x = 1x.7 (Range 540
Exactly what brand do you smoke?
73. I % menthol 3X.X% Long\ 90.3% Filters
In an average day. how many cigarettes do you usually smoke’?
x = 27.2 (Range I-100)
How many cigarettes would you estimate you smoked per day over the past week’?
x = 28.X
On the average. how much of a cigarette do you smoke’?
’ 1 = 9.7% = 21 = 13.3% All = 47.0%
h.
Do you inhale?
Sometime?, = 2.5.X% Alway‘; = 71.2%
7.
How soon after you wake up do you smoke your first cigarette?
X = 29.4 min “Immediately” 11.0%
8.
How does smoking affect your pain’?
M&es pain better Makes pain worse No effect Don’t k’now
9.
Do you feel a need to smoke while you are in pain?
Ye> No
10.
What is the longest time that you have quit smoking?
x = 17.5 months (Range 0 days-l 5 years)
2.
(Ranye
I
I-IOO)
6.0% 3.0% 57.5% 33.6%
56.7Fic 33.3%
that walking tended to make their pain worse, and they endorsed having significantly higher levels of emotional distress based on scores from the SCL-90. A stepwise discriminant function analysis was used to further examine the 10 variables from Table 2 in order to determine which variables were best able to predict differences
Table 2. Comparisons
between smoking and nonsmoking
Variables Age (years) Education (years) Date of pain onset (months) Work-related injury (‘% yes) Walking makes pain worse (% yes) Trouble falling asleep” Takes sleeping medication” Sexual activity (B unsatisfactory) Have you been depressedh SCL-90 global scale (r-scores) “I = “never”; 5 = “every night.” hl = “not at all”; 5 = “extremely.” *p < 0.05. **p < 0.02. ***p < 0.001.
Smokers (n = I 15) 42.0 11.2 68.1 51.7 47.1 4.27 3.10 71.2 3.22 66.8
low back pam patients on pain variables Nonsmoker5
(n = 75)
17. I 12.7 41 .O 20.8 31.3 3.63 2.12 56.5 2.x3 63.3
r 2.43* 3.82*** 2.22* 3.32** 7.1x* 3.37** 2.55* 2.22* 1.9x* 2.43*
Smoking and chronic pain
Table 3. Correlations
107
between the need to smoke when in pain and psychosocial
Tense
Irritable
Nervous”
Anxious”
.24*
.21*
.27**
.25**
No desire for social activity
No desire for recreation
Uses narcotics
Stays in bed
.31**
.27*’
.20*
Need to smoke
Need to smoke
.22*
variables Unsatisfactory social life
.23* Pain is constant
No. of pain descriptors
.23*
.20*
“Physician rated. *p < .05. **p < .Ol.
between the smoking and nonsmoking back pain patients. Eight variables were found to be most useful in discriminating between patient groups. These included (1) sleep disturbances, (2) walking makes pain worse, (3) work-related injuries, (4) age, (5) formal education, (6) duration of pain, (7) relying on sleeping medication, and (8) emotional distress. Sixty-seven percent of the cases were correctly classified into either the smoking or nonsmoking groups for a combined Wilks’ lambda of .72 and a canonical correlation of .53. A comparison was made between smokers who reported needing to smoke when they were in great pain (n = 72) and smokers who reported not needing to smoke when in pain (n = 43) on a number of psychosocial variables. Correlational results are presented in Table 3. Patients who stated that they needed to smoke while in pain showed higher self-rated and physician-rated emotionality and reported being dissatisfied with their social lives. They tended to have little desire for social and recreational activity. They relied on narcotic pain medication, and they were often confined to bed. They described their pain as constant, and they tended to use more pain descriptors when describing their pain, Thus, those patients who showed high emotionality and who were generally inactive were at greater risk for smoking when they were in significant pain. DISCUSSION
There are a number of findings from the results of this study. First, a greater percentage of referrals to a multidisciplinary pain center were found to smoke compared with the general population. Most chronic pain patients who did smoke were heavy smokers and admitted to being dependent on cigarettes. Second, chronic pain patients did not believe that smoking cigarettes increased (or decreased) their subjective pain intensity. The consistent reaction from almost all of the patients (9 1%) was that cigarette smoking either had no effect on their pain, or they were uncertain of its effect. Third, the majority of pain patients who smoked reported an increased need to smoke during those periods when their pain was most severe. Thus, pain patients were found to be at risk for smoking, especially during times when their pain had increased. Also, these patients showed a positive relationship between having a need to smoke and showing considerable emotionality. Finally, differences were found between smokers and nonsmokers on a number of psychosocial variables. Overall, smokers tended to present more maladaptive pain behaviors compared with nonsmokers. These included decreased activity, reliance on medication, and expression of emotional distress. It is unclear why only a few of the patients in this study felt that smoking influenced their
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pain, since past studies found that nicotine acted to decrease pain intensity. There are a number of possible explanations. First, nicotine may have less of an effect in alleviating chronic pain versus acute pain. Most of the published studies that demonstrated an increase in pain tolerance after ingesting nicotine examined patients’ reactions to experimentally induced acute pain. Quite possibly, chronic pain patients respond differently to the physiological effects of nicotine. Second, the fact that one-third of the responders did not know whether smoking affected their pain or not may reflect the paradoxical possibilities of smoking on pain. This is in keeping with Gilbert’s (1979) finding that nicotine increases antonomic arousal yet reduces self-reported anxiety. The affects of nicotine on pain is not direct. Nicotine activates increasing concentrations of norepinephrine and epinephrine in the blood while also possibly increasing a release of beta-dorphin that may mediate a decrease in pain perception. A third possibility is that nicotine may increase arousal while also decreasing the attention the individual gives to painful symptoms or decreasing the need to respond to pain. Further studies are needed to help substantiate these hypotheses. It is also unclear from these results why chronic pain patients who participated in this study and who smoked tended to report an increase in smoking behavior when their pain intensity increased. The pain patients gave a number of anecdotal reasons to account for their increased frequency of cigarette smoking. These included boredom, a need for distraction, anxiety, nervousness, depression, anger, frustration, and enjoyment from the effects of inhaling the smoke. It is difficult, however, to separate the differences between the pharmacological efficacy and the reinforcing efficacy of smoking on pain. A number of studies examining the reinforcing effects of drugs on behavior (Rose, Ananda, & Jarvik, 1983) have pointed out that there are simultaneously both positive and aversive reactions with ingesting any drug. It has been shown in animal studies using cocaine that the act of taking any drug can be very reinforcing (Spealman, 1979). Of particular relevance to this study is the notion that when reinforcers in an individual’s environment are removed, the individual seeks to maintain stable rates of reinforcers (Carroll & Meisch, 1984). This leads to an interesting notion regarding smoking behavior in chronic pain patients. When these patients are deprived of social reinforcers (e.g., work, social, and recreational activity, etc.), they make up for their loss of stimulus by increasing other reinforcing behaviors such as eating and smoking. Thus, social deprivation and lack of positive experiences may play a part in contributing to increased cigarette smoking in chronic pain patients. Anecdotal reports suggest that pain patients tend to overeat and crave sweets, and it has been determined that obese sedentary adults tend to overeat in response to emotions and somatic complaints (Schlundt, Sbrocco, & Bell, 1989). This has implications for designing interventions for those patients who are disabled from their pain and who express an interest in quitting smoking. Efforts should be made to examine the present reinforcers and substitute other behaviors that might help to distract the patient from smoking. One limitation of the results of this study is that the data are correlational in nature. Thus, it can not be determined whether smokers tend to be emotional and express more pain behavior or whether the pain condition actively contributes to the smoking behavior. The data also are based on self-report items, and there was no measurement of the physiological component of smoking and its effect on chronic pain. Another potential problem pertains to the subject population. The majority of the patients in this study had not completed high school, and many came from a lower socioeconomic group than might possibly be found in other chronic pain populations. This may account, in part, for the higher rate of cigarette smokers. It is doubtful, however, that the 54% incidence of cigarette smoking was due solely to demographic factors alone. Replicating this study with other groups of pain patients may prove beneficial.
Smoking and
chronic pain
109
These results point to a need for further study of the incidence of cigarette smoking in chronic pain patients. Both behavioral and physiological influences of smoking need to be examined. This study failed to address whether smoking frequency significantly increased following the onset of the pain. Patients with other types of pain (e.g., headaches, abdominal pain) were not included. Also, further information is needed in understanding the reinforcing effects of cigarette smoking for pain patients who are not referred for treatment of their pain. The results of this initial investigation suggest, however, that chronic pain patients may be at risk for increasing their smoking behavior and that increased pain intensity and emotional distress factors are related to a need to smoke in this select population of pain patients.
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