Physical activity level at work and risk of chronic low back pain: A follow-up in the Nord-Trøndelag Health Study.

Ingrid Heuch,John-Anker Zwart,Knut Hagen,Ivar Heuch,David Meyre

doi:10.1371/journal.pone.0175086

Abstract

BackgroundPhysical activity in leisure time seems to reduce the risk of low back pain, but it is not known whether occupational activity, as recorded in a representative working population, produces a higher or lower risk.ObjectiveTo study associations between physical activity level at work and risk of chronic low back pain.MethodsAssociations were examined in a Norwegian prospective study using data from the HUNT2 and HUNT3 surveys carried out in the whole county of Nord-Trøndelag. Participants were 7580 women and 7335 men who supplied information about physical activity level at work. Levels considered were sedentary work, work involving walking but no heavy lifting, work involving walking and heavy lifting, and particularly strenuous physical work. Nobody in the cohort was affected by chronic low back pain at baseline. After 11 years, participants reported whether they suffered from chronic low back pain. Generalized linear modelling with adjustment for potential confounders was applied to assess associations with risk factors.ResultsIn age-adjusted analyses both women and men showed statistically significant associations between physical activity at work and risk of chronic low back pain, suggesting positive relationships. For particularly strenuous physical work the relative risk of chronic low back pain was 1.30 (95% CI: 1.00–1.71) in women and 1.36 (95% CI 1.17–1.59) in men, compared to sedentary work. Women still showed a general association with activity level after adjustment for education, leisure time physical activity, BMI, smoking and occupational category. In men, the higher risk was only maintained for particularly strenuous work.ConclusionIn this cohort, women had a higher risk of chronic low back pain with work involving walking and heavy lifting or particularly strenuous work, compared to sedentary work. Men participating in particularly strenuous work also experienced a higher risk of chronic low back pain.

Highlights

Low back pain (LBP) is a common disabling condition, and it is one of the most frequent causes of long-term sick leave and disability in Norway
Physical activity in leisure time seems to reduce the risk of low back pain, but it is not known whether occupational activity, as recorded in a representative working population, produces a higher or lower risk
For strenuous physical work the relative risk of chronic low back pain was 1.30 in women and 1.36 in men, compared to sedentary work

Summary

Introduction

Low back pain (LBP) is a common disabling condition, and it is one of the most frequent causes of long-term sick leave and disability in Norway. Among the Norwegian working population, about 32% experience pain in the lower back during any one month [1]. Physical activity is considered to be beneficial, but particular strenuous activities may be associated with increased risk of LBP [3]. In studies of physical activity at work, specific types of work-related exposure seem to provide a higher risk of back pain [3, 4], it is not clear that there is any definite causal relationship [5]. Occupational and leisure time physical activity may in general have opposing effects on health [6]. Physical activity in leisure time seems to reduce the risk of low back pain, but it is not known whether occupational activity, as recorded in a representative working population, produces a higher or lower risk

Methods

Results

Conclusion