People may be getting more willing to report pain

The evidence for an epidemic of low back pain in the United Kingdom rests on the unrelenting rise in sickness and invalidity benefit payments for low back pain since the 1950s.¹ Similar trends have been observed elsewhere in Europe, and the same period has also seen a steady rise in rates of general practice consultations for low back pain.^2,3 Many have argued that these changes do not represent a true rise in the incidence of low back pain but an epidemic of work incapacity attributed to low back pain.¹ Increasing acceptance of low back pain as a reason for sickness certification, particularly in the context of rising unemployment and lack of opportunities for rehabilitation, seems likely to have contributed to this, as have changes in social security provision.^1-4 The underlying assumption is that the actual occurrence of low back pain in the general population has changed very little during the post war period. New data in the BMJ challenges that assumption.⁵

The assumption is difficult to test because of the variety of definitions used in different surveys.⁶ But a paper from Palmer et al overcomes this difficulty: in two separate population surveys in the United Kingdom, 10 years apart and using identical questionnaires, they observed an increase of a third in the prevalence of self reported low back pain.⁵ What is the explanation?

One possibility is the inherent variability of subjective symptom reporting. However, another identical survey in 1993 found a similar figure to the authors' first survey.⁷ This finding argues against large random fluctuations in answers to the question on back pain but does suggest that the increase may have happened during the mid-1990s.

A second explanation is that back conditions have become more common. Some risks may have increased (monotonous sedentary work or dissatisfaction in the workplace, for example^8,9), although others, such as manual handling, have declined. Such factors may possibly have contributed to a changed level of symptom reporting and to the importance placed on symptoms. Palmer et al disagree with that explanation because they observed no concomitant rise in severe back related disability. Yet, if monotonous hours seated at work can exacerbate low back pain, then this may disable because it hinders work, even though it is compatible with the unhindered putting on of socks or tights (their measure of disabling back pain). Nevertheless, changes in risk factors alone could not explain such a sharp rise in self reported low back pain over a short period affecting all adult age groups simultaneously.

Palmer et al's favoured explanation is that general cultural influences have affected awareness and reporting of symptoms. Is there evidence that this can happen? Levels of self reporting of symptoms and episodes of illness seem to be higher now than earlier in the century.¹⁰ Cultural influences on the presentation of painful symptoms are evidenced by postwar changes in the pattern of musculoskeletal morbidity in general practice and the dramatic differences in consultation rates for musculoskeletal conditions between different ethnic groups in the United Kingdom.^2,3 Commentators have described "syndrome shift,"¹¹ in which different patterns of symptom reporting dominate at different times. Attempts have been made to relate such shifts to prevailing climates of medical diagnostics or social circumstances. One historian has concluded that symptom reporting has become increasingly dominated by pain during the past 50 years, speculating that this reflects the increased solitude of modern life.¹²

But why should it be pain in the back in the 1990s rather than another pain? Most low back pain cannot be explained by diagnosable spinal disease,¹ and cultural factors might influence its reporting. Cultural preoccupation with the back is nothing new: rail travel in the 19th century was accompanied by a multiplicity of symptoms and public debate about "railway spine."¹² The rise in work incapacity has focused attention on low back pain. Increasing public knowledge of the "low back pain epidemic," media attention, government reports, and even back pain surveys are all likely to have made back pain a more prominent part of life in the 1990s. The increase in reporting of low back pain may reflect this.

Any explanation must strike a balance between the reality of the pain for the sufferer; the likelihood that mechanical factors can aggravate symptoms; the strong evidence that distress and dissatisfaction in daily life make back pain more likely and more persistent; and the possibility that public attention was increasingly drawn to the back during the 1990s. Whether the rise in symptom reporting reflects the way we live and work or our current pattern of preoccupation with illness, Palmer et al's study provides empirical evidence that it has occurred. Is this finding important? The answer lies in the importance that patients and their doctors attach to the symptoms.

The dominance of a medical model which sees low back pain exclusively in terms of spinal disease and injury may generate inappropriate investigations and treatment and contribute to the persistence of symptoms.^1,13 Neurophysiological advances are helping us to understand how pain can persist in the absence of injury and under the influence of culture and belief. The challenge is how to change the culture and the beliefs and keep faith with the person with the pain.

Reference points
1. Waddell G. The epidemiology of back pain. In: Clinical Standards Advisory Group. Epidemiology review: the epidemiology and cost of back pain. London: HMSO, 1994.
2. Royal College of General Practitioners, Office of Population Censuses and Surveys, Department of Health and Social Security. Morbidity statistics from general practice 1981-82. Third national study. London: HMSO, 1986.
3. McCormick A, Fleming D, Charlton J. Morbidity statistics from general practice. Fourth national study 1991-1992. London: HMSO, 1995.
4. May C, Doyle H, Chew-Graham C. Medical knowledge and the intractable patient: the case of chronic low back pain. Soc Sci Med 1999;48:523-34.
5. Palmer KT, Walsh K, Bendall H, Cooper C, Coggon D. Back pain in Britain: comparison of two prevalence surveys at an interval of 10 years. BMJ 2000;320:1577-8.
6. Dionne CE. Low back pain. In: Crombie IK, Croft PR, Linton SJ, LeResche L, Von Korff M, eds. Epidemiology of pain. Seattle: IASP Press, 1999.
7. Mason V. The prevalence of back pain in Great Britain. London: HMSO, 1994.
8. Barnekow-Bergkvist M, Hedberg G, Janlert U, Jansson E. Determinants of self-reported neck-shoulder and low back symptoms in a general population. Spine 1998;23:235-43.
9. Papageorgiou AC, Macfarlane GJ, Thomas E, Croft PR, Jayson MIV, Silman AJ. Psychosocial factors in the workplace-do they predict new episodes of low back pain? Evidence from the South Manchester back pain study. Spine 1997;22:1137-42.
10. Shorter E. From paralysis to fatigue. A history of psychosomatic illness in the modern era. New York: Free Press, 1992.
11. Kissen DM. The significance of syndrome shift and late syndrome association in psychosomatic medicine. J Nerv Ment Dis 1963;136:34-42.
12. Harrington R. The "railway spine" diagnosis and Victorian responses to PTSD. J Psychosom Res 1996;40:11-4.
13. Hadler NM. Occupational musculoskeletal disorders. 2nd ed. Philadelphia: Lippincott Williams and Wilkins, 1999.