What mediates the inverse association between education and occupational disability from back pain?—A prospective cohort study from the Nord-Trøndelag health study in Norway
Introduction
In most of the western world there is a growing concern about the proportion and socioeconomic consequences of work incapacity from back pain (BP). Early retirement due to BP is considered to be the extreme endpoint of a disabling process (Krause & Ragland, 1994), which is a great burden to the individual and costly for the society (Waddell & Norlund, 2001a; van Tulder, Koes, & Bouter, 1995).
Low socioeconomic status has consistently been associated with increased mortality and morbidity (Mackenbach, Kunst, Cavelaars, Groenhof, & Geurts, 1997). Education is often considered to be the best indicator of socioeconomic status, because it is easy to observe and unlikely to be affected by diseases that begin in adult life. Dionne and colleagues reviewed the scientific evidence on the relation between educational status and measures of the frequency and the consequences of BP, and concluded that no other single trait is so strongly and consistently related to BP disability as formal education (Dionne et al., 2001).
The underlying mechanisms for the inverse relationship between educational attainment and BP disability are poorly understood. Many studies have used socioeconomic status as a measure of occupational exposure, suggesting that the relationship between BP disability and socioeconomic status could be largely related to manual versus non-manual jobs, but evidence from empirical studies are sparse (CSAG Epidemiology Review, 1994). People with low education are more likely to work in physically and psychosocially demanding jobs, and there is empirical evidence that these factors play an important role in the aetiology and prognosis of BP (Hoogendoorn, van Poppel, Bongers, Koes, & Bouter, 1999; Hoogendoorn, van Poppel, Bongers, Koes, & Bouter, 2000) The association between BP disability and socioeconomic status may, however, have different causes and pathways. For example, well-educated people are more likely to be aware of the negative health effects of life style factors such as smoking, obesity, sedentary lifestyle and alcohol consumption. Some of these factors have also been considered as possible risk factors for BP (Leboeuf-Yde, 1999; Leboeuf-Yde, 2000).
Studying possible factors contributing to the explanation of educational inequalities in BP disability may advance our understanding of BP, and educational inequalities in BP disability can only be reduced when the causal mechanisms are understood and when important intermediate factors are identified. Therefore the aim of this study was to examine to what extent the inverse relationship between formal education and disability retirement from BP is mediated by factors related to the working conditions and to the individual lifestyle.
Section snippets
Methods
Data were available from a seven-year prospective population-based cohort study, by merging computerized files with individual data from the national medical insurance system (National Insurance Administration [NIA]), the Nord-Trøndelag Health Survey 1984–86 (HUNT-1), (Holmen et al., 1990) and population registries from the national bureau of statistics (Statistics Norway) at the individual level. The study was approved by the Regional Ethical Committee and by the Data Inspectorate.
Results
From 1987 to 1993 there were 322 women (2.1%) and 393 men (1.7%) between 25 and 59 years of age who were granted disability pension due to back diseases. The general characteristics of the study population are shown in Table 1. The incidence of BP disability increased from 0.2% for those with >13 years of education to 3.3% for those with<9 years of education. Occupational class, four of the five factors related with working conditions, (“Authority to plan your own work”, “Physically demanding
Discussion
The present study indicates that less than 50% of the educational inequalities in BP disability retirement could be explained by occupational class and factors related to working conditions and life style. Working conditions contributed most to the explanation for men, while the three groups of explanatory variables contributed equally for women. Subgroup analyses indicate small differences between full-time and part-time employees, while some differences were found between subcategories of
Acknowledgement
The Nord-Trøndelag health study (HUNT) is a collaboration between the HUNT Research Centre, Faculty of Medicine, Norwegian University of Science and Technology, Verdal; the Norwegian Institute of Public Health; the National Health Screening Service of Norway; and Nord-Trøndelag county council. This study was funded in part by grants from the Norwegian Research Council and the Norwegian Royal Ministry of Social Affairs. The authors would like to thank Dr. Petter Mowinckel at the Diakonhjemmet
References (23)
- et al.
Socioeconomic inequalities in morbidity and mortality in western Europe. The EU working group on socioeconomic inequalities in health
Lancet
(1997) - et al.
A cost-of-illness study of back pain in The Netherlands
Pain
(1995) - CSAG. (1994). Epidemiology review: The epidemiolgy and cost of back pain. Report of a CSAG (Clinical Standards Advisory...
- Dionne, C., Koepsell, T. D., Von Korff, M., Deyo, R. A., Barlow, W. I., & Checkoway, H. (1995). Formal education and...
- et al.
Formal education and back pain: A review
Journal of Epidemiology and Community Health
(2001) - et al.
Socioeconomic factors and disability retirement from back pain—A population-based prospective study in Norway 1983–1993
Spine
(2000) - et al.
A prospective cohort study of risk factors for disability retirement because of back pain in the general working population
Spine
(2002) - Holmen, J., Midthjell, K., Bjartveit, K., Hjort, P. F., Lund-larsen, P. G., et al., 1990. The Nord-Trøndelag health...
- et al.
Physical load during work and leisure time as risk factors for back pain [see comments]
Scandinavian Journal of Work Environment and Health
(1999) - et al.
Systematic review of psychosocial factors at work and private life as risk factors for back pain
Spine
(2000)
Modified work and return to work: A review of the literature
Journal of Occupational Rehabilitation
Cited by (47)
Poverty and pain: Low-SES people are believed to be insensitive to pain
2021, Journal of Experimental Social PsychologyDoes educational attainment increase the risk of low back pain when genetics are considered? A population-based study of Spanish twins
2017, Spine JournalCitation Excerpt :There is an inverse relationship between educational attainment and the severity [11,12] and frequency [13] of LBP; however, only a few studies have investigated educational attainment as a risk factor for LBP. It appears that having a higher level of education reduces the risk of developing activity limiting LBP [14,15], although there are additional factors that need to be considered before definite conclusions can be made, including the influence of gender and genetics. First, the impact gender has on the relationship between educational attainment and LBP has only been considered in a few observational studies.
Musculoskeletal pain at various anatomical sites and socioeconomic position: Results of a national survey
2016, Revue d'Epidemiologie et de Sante PubliquePain among women: Associations with socio-economic factors over time and the mediating role of depressive symptoms
2012, Scandinavian Journal of PainCitation Excerpt :In the present study educational level was associated with pain outcomes while occupational status was unrelated to these variables among women with pain. This has been demonstrated previously, indicating that educational level has a strong effect on pain outcomes, which should not be understood as related to occupational class and/or working conditions [30,37]. Finally, low SES has been associated with increased levels of stress hormones and allostatic load [38–40].
Socioeconomic risk factors for long-term opioid use: A national registry-linkage study
2024, European Journal of Pain (United Kingdom)