Objective: To assess the effect of body mass index (BMI) on pain and function outcomes in the acute and subacute stages of work-related low back pain (LBP).
Methods: A prospective cohort of working-age patients (410 male, 197 female) with recent onset LBP (≤14 days' duration) provided height and weight as part of a study of prognostic factors for back disability. Self-reported pain, functional limitation, and work status were assessed at 1- and 3-month follow-ups.
Results: BMI (kg/m2) was used to categorize participants as normal (31%), overweight (40%), or obese (29%). In prediction analyses, outcomes of pain, functional limitation, and return to work showed no significant variation (P > 0.05) by BMI, with or without controlling for potential confounds.
Conclusions: BMI is not a useful prognostic factor during the acute and subacute stages of work-related LBP.