Back pain and work: Personal factors
Leboeuf-Yde C. Body weight and low back pain. A systematic literature review of 56 journal articles reporting on 65 epidemiologic studies. Spine 2000; 25:226-37.
Summary
This study reviews articles published between 1965 and 1997 about low back pain (LBP) and body weight. The researchers systematically searched Medline and found 65 relevant studies.
32% of the studies reported a positive association between weight and LBP.
This association was not affected by:
- Gender (reported in 15 studies);
- Different measurements of body weight;
- Different definition of LBP; or
- A statistical analysis that took other risk factors in account.
The association was affected by:
- Different study populations;
- Representative study sample; and
- Sample size – the bigger the sample size the stronger the association found.
From the large population studies however, the relation between body weight and LBP was still weak with rate ratios of < 2.
The authors concluded that there is insufficient evidence for a causal link between body weight and LBP.
Leboeuf-Yde C, Kyvik KO, Bruun NH. Low back pain and lifestyle. Part II--Obesity. Information from a population-based sample of 29,424 twin subjects. Spine 1999; 24:779-83; discussion 783-4.
Summary
The researchers in this study wanted to assess whether there is a link between weight and low back pain (LBP), and, if so, whether this link is also associated with gender, age, type of work or smoking. Furthermore, they wanted to explore a possible association between genetics and LBP.
In order to do so, they used the data from a Danish register of twins. Of 29 424 participants, 3751 were identical twins. Participants were sent a questionnaire about their health status, low back issues, BMI, smoking status, work status and work environment.
Results showed that:
- Being underweight was associated with lower risk of LBP: OR 0.6 (95% CI 0.5-0.6);
- Being overweight was associated with a higher risk of LBP, which became stronger with longer duration of LBP;
- Being younger and a male further lowered the risk of LBP for underweight participants: OR 0.4 (95% 0.3-0.4) for men aged 12-20 years;
- Type of work or smoking did not change the results significantly; and
- The association between BMI and LBP could not be reproduced in identical twin pairs who differed from each other in body weight.
The researchers concluded that while there was an association between obesity and low back pain, obesity probably does not cause the pain, although it may have an impact on its duration.
Dempsey, P. G., A. Burdorf, et al. (1997). "The influence of personal variables on work-related low-back disorders and implications for future research." J Occup Environ Med 39(8): 748-59.
Summary
This article is a discussion paper about personal variables for work-related low back disorders. The objective of the researchers is to recommend which personal variables should be taken into account when analysing potential occupational risk factors for developing low back pain.
The authors recommend the following variables to be studied further, because they consider these factors to be correlated with low back pain:
- Age;
- Gender;
- Injury history;
- Relative strength (in relation to job demand, especially in cases where jobs are highly repetitive or contain tasks such as lifting);
- Smoking; and
- Psychosocial variables.
The following factors seemed to have little impact on the development of low back pain:
- Height and weight;
- Pathologies and genetic factors;
- Maximum oxygen uptake; and
- Absolute strength.
Leboeuf-Yde C. Smoking and low back pain. A systematic literature review of 41 journal articles reporting 47 epidemiologic studies. Spine 1999; 24:1463-70
Summary
The authors reviewed 47 articles (1974-1996) that describe the potential relation between smoking and low back pain.
A positive association between smoking and LBP was found in 24 of 47 studies (51%). In the larger sample studies (> 3000 participants) the strength of the association remained modest but was more consistent. Estimated rate ratio was less than 2.
A dose-response association between smoking and LBP could only be found in the largest study (> 30,000 participants).
The authors conclude that smoking should not be considered a definite cause of LBP but rather a weak risk indicator.
Hildebrandt VH, Bongers PM, Dul J, van Dijk FJ, Kemper HC. The relationship between leisure time, physical activities and musculoskeletal symptoms and disability in worker populations. International Archives of Occupational & Environmental Health 2000; 73:507-18.
Summary
This study by Dutch researchers describes the relationship between physical activity in leisure time and the risk for musculoskeletal problems. 39 studies (1975-1999) on this topic were reviewed.
The studies showed that 50% of workers participated in sports, with a mean number of 4.1 h per week.
There were weak or no associations between physical activity, participation in sport and musculoskeletal symptoms in those studies.
However workers with many sedentary activities in leisure time do have higher rates of low back pain and sick leave. Furthermore, for workers with sedentary tasks, non-participation in sport and having many sedentary leisure activities seems to be associated with a higher prevalence of symptoms.
The researchers conclude that workers should be encouraged to participate in sports and other active past-times as a way of avoiding inactivity.