Study Design. A cross-sectional population-based study.
Objective. To examine the association between body mass index and chronic low back pain, with adjustment for potential confounders.
Summary of Background Data. Although many studies have investigated this association, it is still unclear whether there is a general relationship between body mass index and low back pain which applies to all populations.
Methods. This study is based on data collected in the HUNT 2 study in the county of Nord-Trøndelag in Norway between 1995 and 1997. Among a total of 92,936 persons eligible for participation, 30,102 men and 33,866 women gave information on body mass index and indicated whether they suffered from chronic low back pain (69% participation rate). A total of 6293 men (20.9%) and 8923 women (26.3%) experienced chronic low back pain. Relations were assessed by logistic regression of low back pain with respect to body mass index and other variables.
Results. In both sexes, a high body mass index was significantly associated with an increased prevalence of low back pain. In men the estimated OR per 5 kg/m2 increase in body mass index was 1.07 (95% CI: 1.03–1.12) and in women 1.17 (95% CI: 1.14–1.21), after adjustment for age, with a significantly stronger association in women. Additional adjustment for education, smoking status, leisure time physical activity, employment status, and activity at work hardly affected these associations. No interactions were found with most other factors.
Conclusion. This large population-based study indicates that obesity is associated with a high prevalence of low back pain. Further studies are needed to determine if the association is causal.
In a cross-sectional study of 30,102 men and 33,866 women in Norway, high values of body mass index were related to a high prevalence of low back pain in both sexes. The relationship was not affected by adjustment for education, smoking, physical activity, or work status.
From the *Department of Neurology, Oslo University Hospital, Oslo, Norway; †Department of Neuroscience, Norwegian University of Science and Technology, Trondheim, Norway; ‡Norwegian National Headache Centre, Department of Neurology, St. Olavs Hospital, Trondheim, Norway; §Department of Mathematics, University of Bergen, Bergen, Norway; ¶National Centre for Spinal Disorders, St. Olavs Hospital, Trondheim, Norway; and ‖Faculty of Medicine, University of Oslo, Oslo, Norway.
Acknowledgment date: March 19, 2009. Revision date: May 13, 2009. Acceptance date: July 11, 2009.
The manuscript submitted does not contain information about medical device(s)/drug(s).
No funds were received in support of this work. No benefits in any form have been or will be received from a commercial party related directly or indirectly to the subject of this manuscript.
This study was approved by the Regional Committee for Ethics in Medical Research, and the HUNT study was also approved by the Norwegian Data Inspectorate.
Address correspondence and reprint requests to Ingrid Heuch, Department of Neurology, Oslo University Hospital, N-0407 Oslo, Norway; E-mail: email@example.com