Low back pain is associated with sleep disturbance: a 3-year longitudinal study after the Great East Japan Earthquake

BACKGROUND: Low back pain and sleep disturbance are common health problems worldwide which are also commonly observed among people after natural disasters. These symptoms are well known to coexist, and recent reports have indicated that sleep disturbance is a risk factor for low back pain. However, the influence of low back pain on sleep disturbance has rarely been assessed; therefore, this study aimed to clarify the association of low back pain with sleep disturbance, especially focusing on the frequency of low back pain, using 3-year cohort data after the Great East Japan Earthquake. METHODS: This study used the data obtained from people living in the disaster-affected areas after the Great East Japan Earthquake (n = 2,097). Low back pain and sleep disturbance were assessed at 4, 5, 6, and 7 years after the disaster. The frequency of low back pain was defined as the number of low back pain episodes at and before the evaluation time point and categorized into five groups such as absence, 1, 2, 3, and 4 at the fourth time point and four groups such as absence, 1, 2, and 3 at the third time point. Multivariate logistic regression analyses were conducted to assess the association of low back pain with sleep disturbance. RESULTS: Low back pain was significantly associated with sleep disturbance, and the association was stronger in participants with more frequent low back pain (adjusted odds ratios [95% confidence intervals],1.46 [1.10–1.95] in “1”; 2.02 [1.49–2.74] in “2”; 2.38 [1.67–3.40] in “3”; and 4.08 [2.74–6.06] in “4” in the frequency of low back pain) (P for trend < 0.001). Furthermore, antecedent low back pain was significantly associated with new-onset sleep disturbance, and the association was robust in more frequent low back pain (adjusted odds ratios [95% confidence intervals],1.60 [1.05–2.44] in “1”; 1.96 [1.20–3.21] in “2”; and 2.17 [1.14–4.14] in “3” in the frequency of low back pain) (P for trend = 0.007). CONCLUSION: Our study showed that low back pain is strongly associated with sleep disturbance. Attention should be paid to low back pain to prevent and treat sleep disturbance, especially focusing on chronicity of low back pain.