Supplementary file 1_Associations of different types of physical activity (PA) with musculoskeletal disorders (MSDs) at nine body sites in firefighters.docx

BackgroundMusculoskeletal disorders (MSDs) are one of the global health and economic burdens. They have a high prevalence in occupational populations such as firefighters. Besides poor postures and sedentary work, inappropriate physical activity (PA) is recognized as a relevant risk factor for MSDs. However, the independent associations between different types of PA and MSDs have not been fully investigated.
ObjectiveWe systematically investigated the associations of occupational physical activity (OPA), leisure-time physical activity (LTPA) and transport-related physical activity (TPA) with the onset, pain intensity and frequency of MSDs at nine body sites. We quantified their differential effects, so as to provide scientific evidence for the precise prevention and control of MSDs in high-workload occupational populations.
MethodsMultiple linear regression, logistic regression and polynomial regression were applied to analyze the distinct effects of different types of PA (OPA, LTPA, TPA) on the onset, intensity, frequency and cumulative number of painful sites of MSDs at nine body sites.
ResultsOPA was associated with the risks of the onset, increased pain intensity and prolonged duration of MSDs at nine body sites (p < 0.05). Only high-level LTPA was associated with the onset and increased pain intensity of MSDs at specific body sites (p < 0.05). In the state of high-intensity OPA, it was associated with the exacerbated accumulation of MSDs at multiple body sites.
ConclusionHigh OPA was a key risk factor for MSDs, and high LTPA was a risk factor for MSDs at specific body sites.

背景 肌肉骨骼疾病（Musculoskeletal disorders, MSDs）是全球范围内的卫生与经济负担之一，在消防员等职业人群中具有较高患病率。除不良姿势与久坐工作外，不恰当的身体活动（Physical activity, PA）被认定为肌肉骨骼疾病的相关危险因素。然而，不同类型身体活动与肌肉骨骼疾病之间的独立关联尚未得到充分探究。
目的 本研究系统探讨了职业性身体活动（Occupational physical activity, OPA）、闲暇时间身体活动（Leisure-time physical activity, LTPA）以及交通出行相关身体活动（Transport-related physical activity, TPA）与9个身体部位肌肉骨骼疾病的发病情况、疼痛强度及发作频率之间的关联，并量化了不同类型活动的差异化影响，旨在为高负荷职业人群肌肉骨骼疾病的精准防控提供科学依据。
方法 本研究采用多元线性回归、逻辑回归与多项式回归模型，分析不同类型身体活动（OPA、LTPA、TPA）对9个身体部位肌肉骨骼疾病的发病情况、疼痛强度、发作频率以及疼痛部位累积数量的差异化影响。
结果 职业性身体活动与9个身体部位肌肉骨骼疾病的发病风险、疼痛强度升高以及病程延长均存在显著关联（p < 0.05）。仅高水平闲暇时间身体活动与特定身体部位肌肉骨骼疾病的发病及疼痛强度升高存在显著关联（p < 0.05）。在高职业性身体活动水平状态下，其与多身体部位肌肉骨骼疾病的累积发病加重存在关联。
结论 高水平职业性身体活动是肌肉骨骼疾病的关键危险因素，而高水平闲暇时间身体活动则是特定身体部位肌肉骨骼疾病的危险因素。