Assessment of potential risk factors for new onset disabling low back pain in Japanese workers: findings from the CUPID (cultural and psychosocial influences on disability) study.
Kawaguchi M et al. BMC Musculoskelet Disord. 2017;18:334. 

Kawaguchiらは、
日本人労働者の縦断データを用いて、
腰痛の既往歴と長時間労働が、腰痛の新規発症リスクになっていることを見出しました。
研究結果はBMC Musculoskeletal Disordor誌に発表されました。

研究は東京近郊の腰痛ではない労働者955人を1年間追跡したものです。
追跡中58人が新たに腰痛を発症しました。
追跡開始時の調査で、
腰痛の既往歴があった人が2.8倍（Odds Ratio 2.8, 95% CI:1.6-4.9）、
長時間労働（週60時間以上の労働；80hr/月以上）のあった人が1.6倍（OR 1.8, 95% CI: 1.0-3.5）
新規腰痛発症のリスクが高くなっていました。

論文の詳細（全文）はこちら。

Abstract
BACKGROUND: Most studies of risk factors for new low back pain (LBP) have been conducted in Western populations, but because of cultural and environmental differences, the impact of causal factors may not be the same in other countries. We used longitudinal data from the Cultural and Psychosocial Influences on Disability (CUPID) study to assess risk factors for new onset of disabling LBP among Japanese workers.
METHODS: Data came from a 1-year prospective follow-up of nurses, office workers, sales/marketing personnel, and transportation workers, initially aged 20-59 years, who were employed in or near Tokyo. A baseline questionnaire included items on past history of LBP, personal characteristics, ergonomic work demands, and work-related psychosocial factors. Further information about LBP was collected at follow-up. Analysis was restricted to participants who had been free from LBP during the 12 months before baseline. Logistic regression was used to assess baseline risk factors for new onset of disabling LBP (i.e. LBP that had interfered with work) during the 12 months of follow-up.
RESULTS: Among 955 participants free from LBP during the 12 months before baseline, 58 (6.1%) reported a new episode of disabling LBP during the 12-month follow-up period. After mutual adjustment in a multivariate logistic regression analysis, which included the four factors that showed associations individually (p < 0.1) in analyses adjusted only for gender and age, the highest odds ratio (OR) was for past history of LBP (2.8, 95% [confidence interval {CI}]: 1.6-4.9), followed by working ≥60 h per week (1.8, 95% CI: 1.0-3.5) and lifting weights ≥25 kg by hand (1.6, 95% CI: 0.9-3.0). When past history of LBP was excluded from the model, ORs for the remaining risk factors were virtually unchanged.
CONCLUSIONS: Our findings suggest that among Japanese workers, as elsewhere, past history of LBP is a major risk factor for the development of new episodes of disabling back pain. They give limited support to the association with occupational lifting that has been observed in earlier research, both in Japan and in Western countries. In addition, they suggest a possible role of long working hours, which merits further investigation.