BACKGROUND Musculoskeletal disorders, and in particular low-back pain (LBP), are common among blue collar workers. In the work environment, both physical- and psychosocial risk factors exist. Working in warehouses in Denmark involve large quantities of occupational lifting, high work pace and a low degree of influence at work. This study investigates both acute and long-term associations between physical- and psychosocial work environmental factors and risk of LBP in warehouse workers. The specific study aims are to investigate 1) exposure-response associations between quantity of occupational lifting and short-term (day-to-day) changes in LBP, 2) the influence of accumulated workdays and rest days during a working week on LBP, 3) long-term association between occupational lifting exposure and LBP when assessed over 1 year, and 4) the role of psychological and social factors on the above associations. METHODS The present study is designed as a 1-year prospective cohort study that will examine full-time warehouse workers from up to five retail chains in Denmark. Study aims 1 and 2 will be addressed using objective data based on company records with information on weight of all the goods handled by each warehouse worker during every single workday for 3 weeks. During this period, each worker will reply to text messages received before and after every workday (also on days off work) in which study participants will score their pain in the low back, bodily fatigue and perceived mental stress (scale 0-10). Long-term pain development is assessed using questionnaire surveys before and after 1 year. Further, pressure pain threshold (PPT) will be measured for selected trunk extensor muscles in approximately 50 workers using algometry along with measurements of maximal trunk extensor strength. Associations are modelled using linear mixed models with repeated measures between variables and LBP controlled for relevant confounders. DISCUSSION This study provides knowledge about the acute and long-term associations between physical- and psychosocial work environmental factors and LBP. The obtained data will have the potential to provide recommendations on improved design of the working week to minimize the risk of LBP among warehouse workers, and may potentially enable to identify a reasonable maximum lifting threshold per day (ton lifted/day).

中文翻译：

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腰背痛的身体和社会心理工作环境危险因素：一项为期1年的前瞻性队列研究方案。

背景技术肌肉骨骼疾病，尤其是下腰痛（LBP）在蓝领工人中很常见。在工作环境中，存在身体和社会心理风险因素。在丹麦的仓库中工作涉及大量的职业提升，较高的工作节奏和较低的工作影响力。这项研究调查了物理和社会心理工作环境因素与仓库工人的LBP风险之间的急性和长期联系。具体研究的目的是调查1）职业提升量与LBP的短期（日常）变化之间的暴露-反应关联，2）工作周中累积的工作日和休息日对LBP的影响， 3）评估1年以上时，职业举重暴露与LBP之间存在长期联系，（4）心理和社会因素在上述联想中的作用。方法本研究旨在进行为期1年的前瞻性队列研究，该研究将研究丹麦多达5个零售连锁店的全职仓库工人。研究目标1和2将使用基于公司记录的客观数据解决，该信息包含有关每个仓库工人在每个工作日内3周内搬运的所有货物重量的信息。在此期间，每个工作人员将回复每个工作日前后（也包括下班日）收到的文本消息，在该消息中，研究参与者将对他们的腰背疼痛，身体疲劳和感觉到的精神压力进行评分（0-10级）。在1年之前和之后，通过问卷调查评估长期疼痛的发展。进一步，压力疼痛阈值（PPT）将使用航向测量法测量大约50名工人的选定躯干伸肌，并测量最大躯干伸肌的力量。关联使用线性混合模型建模，变量之间重复测量，并为相关混杂因素控制LBP。讨论本研究提供有关身体和社会心理工作环境因素与LBP之间的急性和长期关联的知识。所获得的数据将可能为改进工作周的设计提供建议，以最大程度地降低仓库工人的LBP风险，并可能潜在地确定每天合理的最大起重阈值（起重吨/天）。