Lifestyle factors associated with prevalent and exacerbated musculoskeletal pain after the Great East Japan Earthquake: a cross-sectional study from the Fukushima Health Management Survey
Authors:   on behalf of the Mental Health Group of the Fukushima Health Management Survey, Jinnouchi Hiroshige , Ohira Tetsuya , Kakihana Hironobu , Matsudaira Ko , Maeda Masaharu , Yabe Hirooki , Suzuki Yuriko , Harigane Mayumi , Iso Hiroyasu , Kawada Tomoyuki , Yasumura Seiji , Kamiya Kenji 
Published: May 2020

Abstract
Background
While the prevalence of post-disaster musculoskeletal pain has been documented, its associated disaster-related factors have not been investigated. This study was to investigate the association of lifestyle factors associated with musculoskeletal pain after the Great East Japan Earthquake.

Methods
We conducted a cross-sectional study of 34,919 participants, aged 40–89 years, without any major disabilities at about 1 year after the disaster. The participants were asked about their musculoskeletal pain (low back and limb pain) and lifestyle factors: use of evacuation shelters or temporary housing at any point of time, job loss after the disaster, decreased income after the disaster, current smoking status, current drinking status, lack of sleep, regular exercise, and participation in recreational or community activities. Furthermore, psychological factors, such as traumatic reactions, psychological distress, and uncomfortable symptoms, affecting musculoskeletal pain were assessed. We used multinomial logistic regression analysis to calculate odds ratios of each lifestyle factor for prevalent and prevalent plus exacerbated musculoskeletal pain.

Results
Musculoskeletal pain prevalence was 32.8%: 27.6% for prevalent and 5.2% for prevalent plus exacerbated musculoskeletal pain. Multivariable adjusted odds ratios and 95% confidence intervals of lifestyle factors associated with prevalent and prevalent plus exacerbated musculoskeletal pain were as follows: shelter use (prevalent: 1.02, 0.96–1.08; exacerbated: 1.44, 1.29–1.60), job loss (prevalent: 1.03, 0.96–1.10; exacerbated: 1.30, 1.16–1.47), decreased income (prevalent: 1.13, 1.05–1.21; exacerbated: 1.29, 1.14–1.45), current heavy drinking (prevalent: 1.33, 1.21–1.47; exacerbated: 1.38, 1.14–1.68), insomnia (prevalent: 1.22, 1.15–1.29; exacerbated: 1.50, 1.36–1.65), exercising almost daily (prevalent: 0.83, 0.77–0.91; exacerbated: 0.80, 0.68–0.95), and participating in community activities often (prevalent: 0.83, 0.75–0.92; exacerbated: 0.76, 0.61–0.95).

Conclusions
Prevalent and exacerbated musculoskeletal pain were inversely associated with exercising almost daily and participating in recreational or community activities sometimes or often, and positively associated with decreased income, current heavy drinking, and insomnia. Besides, the use of evacuation shelters or temporary housing/job loss was positively associated only with exacerbated musculoskeletal pain. These results suggest that post-disaster lifestyle factors are potentially associated with musculoskeletal pain. To achieve better post-disaster pain management, further studies are needed to confirm the consistency of these results in other disasters and to highlight the underlying causative mechanisms.