Background: Low back pain and obesity are both major public health problems however the relationship between body composition and low back pain in men is unknown. Therefore, the aim of this study was to examine the relationship between body composition and low back pain and disability in a population-based sample of men.
Methods: 978 male participants from the Geelong Osteoporosis Study were invited to participate in a follow up study in 2006. Participants completed questionnaires on sociodemographics and health status. Low back pain was determined using the validated Chronic Back Pain Grade Questionnaire and the presence of mood disorders was assessed using the Hospital Anxiety Depression Scale. Body composition was measured using dual energy x-ray absorptiometry.
Results: Of the 820 respondents (84% response rate), 124 (15%) had high intensity low back pain and/or disability. Participants with high intensity pain and/or disability were older, more likely to have a mood disorder, less likely to have completed secondary school and more likely to have poor mobility than those with no or low back pain and disability (p<0.002 for all). Low back pain was associated with higher BMI (28.7±0.4 vs 27.3±0.2 kg/m2, p=0.02) and waist-hip ratio (0.97±0.006 vs 0.96±0.006, p=0.04), with increased tendency towards having a higher fat mass index (8.0 vs 7.6 kg/m2, p=0.08), but not fat-free mass index (p=0.68). The relationships between back pain and measures of obesity were stronger in those with a mood disorder, particularly for waist-hip ratio (p=0.05 for interaction) and fat mass index (p=0.06 for interaction).
Conclusion: In a population-based sample of men, high intensity low back pain and/or disability were associated with increased levels of obesity, particularly in those with mood disorders. This provides evidence to support a biopsychosocial interaction between mood disorders and obesity with low back pain.