Impact of Psychosocial Factors in Patients with Chronic Low Back Pain

Study shows that somatization and low job security are independently associated with low back pain prevalence.

In “Are Psychosocial Factors Associated With Low Back Pain and Work Absence for Low Back Pain in an Occupational Cohort?,” their study exploring the impact of psychosocial factors on low back pain and absence from work, published in The Clinical Journal of Pain, Urquhart et al used univariate and multivariate analyses with binary logistic regression of the data obtained from validated questionnaires to show that somatization and low job security are independently associated with low back pain (LBP) prevalence.

Analysis also revealed that negative beliefs, pain catastrophizing (irrational thoughts of negativity), reduced job satisfaction, and a high degree of occupational support were independently associated with duration of leave time from work from LBP.1

The study population pool in this retrospective analysis was derived from nurses from three medical centers in Victoria, Australia (n = 3,086) of which 1,111 signed informed consent and were eligible to participate in the study (response rate was 38.6%). The study population was interviewed via self-administered questionnaires that assessed demographics, occupational activities, musculoskeletal symptoms, physical functioning, and psychosocial functioning. The prevalence of LBP was assessed using the Nordic Questionnaire, which asked if lower back pain lasting longer than one day resulted in absence from work in the past 12 months. The Back Beliefs Questionnaire was used to assess conceptions of back pain, including negative beliefs, pain catastrophizing, resilience, and somatization. The Pain Catastrophizing Scale was used to quantify the feature of catastrophizing, which involves negatively perceiving current pain, or anticipating negative outcomes from future pain experiences.

The somatization subscale of the Brief Symptoms Inventory was used to assess for somatization, the manifestation of psychological stress in somatic form. The Connor-Davidson Resilience Scale was used to assess resilience, the ability to overcome misfortune or change. The Karasek model of job control and demand was used to examine occupational psychosocial factors. Job strain was determined by the composite variables for job control and job demand. Other endpoints that were assessed by ordinal ranking on questionnaires included job satisfaction, job security, and job support. The analytic sample was examined using univariate and multivariate analyses to test the individual effects of each psychosocial factor (unique to the patient or to the work environment) on prevalence of low back pain and occupational leave rates. Binary logistic regression with the SPSS Statistics 17.0 program was used.

The data gleaned from the 38% of qualified responders (1,111 of 3,086) was used for analysis. Slightly more than 50% (55.7%) self-reported presence of LBP in the past 12 months. Analysis of the characteristics of responders showed that they were nearly matched for most items, including female gender, body mass index, mean age in fourth decade, and hourly work duration. After adjustment for age, gender, and BMI in multivariate analyses, low job security and presence of somatization were independently associated with LBP based on odds ratios with 95% confidence intervals with P-value < 0.05 for statistical significance.

An occupational attrition rate of 29.7% was reported amongst those with LBP over the past 12-month period. Pain catastrophizing and negative beliefs about back pain were independently associated with occupational attrition after controlling for confounding variables in the regression analysis. Finally, the regression model showed that low job satisfaction and high job support were associated with leave from work due to LBP.

Commentary from Dr. Mitchell

Low back pain due to various musculoskeletal etiologies is a major burden on quality of life as well as on the economy. Due to the dramatic lifetime prevalence of low back pain in the general population of nearly 50% 2, this article is very relevant. Statistical analysis was thorough, with multivariate and univariate logistic regression used to control for variables. The study explored how occupational factors and personal qualities impact the perception and response to pain. In this study, it was determined that pain catastrophizing and acquisition of negative beliefs about one’s pain are associated with lower back pain. Low job satisfaction and high job support are independently associated with work leave for low back pain. It is necessary to continue this study longitudinally to observe if these trends persist, as a 12-month duration is suboptimal to draw definitive conclusions.

Of course this study is not externally valid given the parochial nature of the study population—middle-aged, female nurses from Australia. There may be underlying factors intrinsic to the field of nursing that render them especially vulnerable to the psychosocial impact of pain. Nurses often care for patients complaining of back pain in the hospital. Health care workers, in general, are susceptible to factitious disorder, malingering, and somatization given the nature of their work. They witness the benefits of infirmity, the proverbial “sick role,” as many of their patients take leave of work and receive the attention of loved ones. Different professions require different amounts of manual labor. The field of nursing is not only vulnerable to mirroring of the “sick role,” but requires more manual labor than other professions, which limits the extrapolation of the data. In addition, men, who are generally more physically active than women, were not studied. The differences in perceptions and prevalence of low back pain amongst different professions should be studied further.

The low responder rate of 38% is another limitation of this study. Low back pain and work leave may be underreported due to severe debility that precludes participation in the study or busy work scheduling.The work attrition due to work-related low-back pain and/or individual psychosocial stressors may be an underestimate as the study favors those out of work with ample time and motivation to complete the questionnaire. There may be a subset of nurses who suffer from work-related low-back pain, yet are resilient enough to withstand it and continue to work. This same population may be too busy to complete the questionnaire as it is not mandatory. Also, the retrospective design leaves the study open to recall bias amongst the limited responders. Given that greater than 50% of the data is unknown and prone to such memory bias, we should apply the data judiciously.

Each individual brings his or her own experiences to a situation. In any study, it is difficult to anticipate and control for the variability of personal qualities and circumstances. Chronic pain syndromes are created by the complex interaction of genetic and environmental factors. Various genetic polymorphisms causing aberrant signaling within the serotonergic and adrenergic pathways have been associated with susceptibility to musculoskeletal pain.8 In addition, individual differences in mental schemata and coping strategies will no doubt influence the way in which the body reacts to occupational stress. Undue emotional distress, somatic awareness, psychosocial stress, and catastrophizing amplify pain mechanisms.8 The mental schema of thinking something is worse than it actually is the basis of catastrophizing, which can influence occupation attrition rates. Catastrophizing is the process of entering an experience with negative expectations, which often results in poor outcomes due to poor coping and self-fulfilling prophecy of one’s own doom.Maladaptive processing of an external conflict, such as job-related stress, often leads toaberrant signaling transduction that leads to increased release of inflammatory cytokines and vulnerability to somatization and pain.2 Somatization has been found in several studies to be associated with development of chronic back pain.4 Biofeedback, cognitive-behavioral therapy, and physical exercise are possible conservative means of managing stress and averting somatization and pain.5-7,9

Thus, as genetically diverse creatures, humans carry the burden of diverse, unexpected reactions to environmental stressors. For this reason, pain management is not a field of systematic protocols, but one of individualization, patient-focused care. Identification of an adverse work environment, as well as faulty mental coping mechanisms, may be the first steps in averting the pathogenesis of chronic pain and limiting occupational attrition rates.

Amber N. Mitchell is a neurology resident at Albany Medical Center Hospital

References:

1. Urquhart DM, Kelsall HL, Hoe VC, Cicuttini FM, Forbes AB, Sim MR. Are Psychosocial Factors Associated With Low Back Pain and Work Absence for Low Back Pain in an Occupational Cohort? Clin J Pain. 2013 Jan 30. [Epub ahead of print].

2. McBeth J, Jones K. Epidemiology of chronic musculoskeletal pain. Best Pract Res Clin Rheumatol. 2007;21:403-25.

3. Freemont AJ. The cellular pathobiology of the degenerate intervertebral disc and discogenic back pain. Rheumatology (Oxford). 2009 Jan;48(1):5-10.

4. Pincus T, Burton AK, Vogel S, Field AP.A systematic review of psychological factors as predictors of chronicity/disability in prospective cohorts of low back pain. Spine (Phila Pa 1976). 2002 Mar 1;27(5):E109-20.

5. Katsamanis M, Lehrer PM, Escobar JI, Gara MA, Kotay A, Liu R. Psychophysiologic treatment for patients with medically unexplained symptoms: a randomized controlled trial. Psychosomatics. 2011 May-Jun;52(3):218-29.

6. Staudenmayer H.Psychological treatment of psychogenic idiopathic environmental intolerance. Occup Med. 2000 Jul-Sep;15(3):627-46.

7. Chandler C, Bodenhamer-Davis E, Holden JM, Evenson T, Bratton S. Enhancing personal wellness in counselor trainees using biofeedback: an exploratory study. Appl Psychophysiol Biofeedback. 2001 Mar;26(1):1-7.

8. Diatchenko L, Fillingim RB, Smith SB, Maixner W. The phenotypic and genetic signatures of common musculoskeletal pain conditions. Nat Rev Rheumatol. 2013 Apr 2. doi: 10.1038/nrrheum.2013.43. [Epub ahead of print].

9. Henschke N, Ostelo RW, van Tulder MW, Vlaeyen JW, Morley S, Assendelft WJ, Main CJ. Behavioural treatment for chronic low-back pain. Cochrane Database Syst Rev. 2010 Jul 7;(7):CD002014.