Factors associated with care-seeking for low back pain when genetics and the familial environment are considered.

BACKGROUND: Low back pain (LBP) is the leading cause of disability worldwide. Care-seekers for LBP cause substantial economic burden to governments and the healthcare system. OBJECTIVE: To investigate lifestyle and health-related factors associated with care-seeking (including pain medication use) in individuals experiencing LBP, after controlling for important genetic and early environmental confounders through the use of a within-twin pair case-control design. DESIGN: A secondary analysis of observational longitudinal data, derived from the Australian Twin low BACK pain (AUTBACK) study, was performed on 66 twin pairs that presented with similar symptoms of LBP at baseline but became discordant for care-seeking behaviour over one month. METHODS: Subjective and objective assessment of pain intensity, disability, depression, sleep quality, physical activity and body mass index were performed. Data was analysed using stepwise conditional logistic regression in two stages: within-pair case-control for monozygotic and dizygotic twins together; and within-pair case-control analysis of monozygotic twins only. Results were expressed as odds ratios (OR) and 95% confidence intervals (CI). RESULTS: Higher LBP intensity (OR 2.9; 95% CI 1.3-6.8) and poorer sleep quality (OR 10.9; 95% CI 1.5-77.7) were the main factors that increased the likelihood of care-seeking for LBP. These associations remained significant and increased in magnitude after adjusting for genetic confounding. CONCLUSIONS: Individuals with higher LBP intensity and worse sleep quality are more likely to seek care for LBP, and this relationship is likely to be causal after adjustment of familial and genetic confounding.