Impact of Stress, Obesity and Ergonomics on Chronic Pain

I.    Stress (e.g., psychosocial factors) increases the risk of chronic pain

A cohort study by Macfarlane et al concluded psychosocial factors may be as important as biomechanical dysfunctions in determining the onset of chronic pain symptoms.

  • Macfarlane GJ, Hunt IM and Silman AJ 2000.  Role of mechanical and psychosocial factors in the onset of forearm pain: parospective population based study.  BMJ (online) 321:676, September 16.

Spies-Dorgelo et al when evaluating the severity of wrist and hand symptoms concluded that the severity of symptoms appear to be associated not only with physical factors, but also with psychosocial and socio-demographic factors.

  • Spies-Dorgelo MN, van der Windt WM, et al 2007.  Hand and writs problems in general practice - patient characteristics and factors related to symptom severity. Rheumatology, Vol 46:11, Pp. 1723-1728.

Cole et al concluded that the stress of low social support at work and high job insecurity were independent predictors of restricted activity due to musculoskeletal disorders

  • Cole DC, Ibrahim SA, Shannon HS et al 2001.  Work correlates of back problems and activity restriction due to musculoskeletal disorders in the Canadian national population health survey (NPHS) 1994–5 data. Occupational Environmental Medicine 58:728-734 doi:10.1136/oem.58.11.728

In a study involving 20,386 female and 4,764 Finnish public sector employees, Laine et al found that job stress is associated with the risk of disability pension.

  • Laine S, Gimeno D, Virtanen M, et al 2009. Job strain as a predictor of disability pension: the Finnish Public Sector Study.  Journal Epidemiology and Community Health 63:24-30 doi:10.1136/jech.2007.071407

II.  Obesity increases the risk of chronic pain

This large population-based study indicates that obesity is associated with a high prevalence of low back pain

  • Heuch I, Hagen K, Heuch I, Nygaard Ø, Zwart JA 2010.  The impact of body mass index on the prevalence of low back pain: the HUNT study. Spine (Phila Pa 1976). Apr 1;35(7):764-8.

Results of this study involving nearly 30,000 Norwegian men and women indicated that obesity increased the risk of chronic pain by 20 percent, while moderate exercise (1 - 2 hours/week) reduced the same in both men and women.

  • Nilsen TI, Holtermann A, Mork PJ 2011. Physical exercise, body mass index, and risk of chronic pain in the low back and neck/shoulders: longitudinal data from the Nord-Trondelag Health Study. American  Journal Epidemioogy. . 2011 Aug 1;174(3):267-73. Epub 2011 Jun 1.

III. Poor Ergonomics increases the risk of chronic pain

The results suggest that cumulative occupational exposure to lifting or carrying and extreme forward bending increases the risk for developing symptomatic osteochondrosis or spondylosis of the lumbar spine.

  • Seidler A, Heiskel H, Bolm-Audorff U, et al, 2001. The role of cumulative physical work load in lumbar spine disease: risk factors for lumbar osteochondrosis and spondylosis associated with chronic complaints. Occupational  Environmental Medicine 2001;58:735 746 doi:10.1136/ oem. 58.11.73

My research (statistical analysis on five years of subjective pain and outcome profiles) suggest that in the presence of one or more of the above contriubuting factors, chronic subjective musculoskeletal pain ratings can be increased by a factor of 0.25 (x+0.25x) to 0.50 (x+0.50x).