Approximately 2.4 million janitors work in the United States. High physical workload may explain a lost-work days rate 2.7 times that of other occupations. Information is limited about non-physical workload factors for janitors and their relations to injuries. For this retrospective cross-sectional study, specially designed, pre-tested questionnaires were distributed to full-time janitor members of a union for two six-month sequential intervals. Questions addressed mental workload (modified NASA Task Load Index), job satisfaction (Andrews and Withey Job Satisfaction Scale), stress (Perceived Stress Scale-4 [PSS-4], and the Single Item Stress Scale [SISS]), physical fitness, and occupational injury experiences. Descriptive and multivariable analyses, with bias adjustment, were conducted. A decreased risk of injury was associated with increased job satisfaction (expressed as a risk ratio (RR): 0.91 [95% confidence interval (CI): 0.83, 0.97]) and increased physical fitness (0.89, [0.83, 0.96]). A highly suggestive increased risk of injury was associated with increased mental workload (1.07, [1.00, 1.15]).

在美国，大约有240万管理员。较高的体力劳动量可能导致失业天数是其他职业的2.7倍。关于看门人的非体力工作量因素及其与伤害的关系的信息是有限的。对于这项回顾性横断面研究，经过特别设计，预先测试的问卷以两个六个月的连续时间间隔分发给工会的专职看门人。这些问题涉及精神工作量（修改后的NASA任务负荷指数），工作满意度（Andrews和Withey工作满意度量表），压力（感知压力量表4 [PSS-4]和单项压力量表[SISS]），身体健康状况，和职业伤害经历。进行描述性和多变量分析，并进行偏差调整。受伤风险的降低与工作满意度的提高有关（以风险比（RR）：0.91 [95％置信区间（CI）：0.83，0.97]表示）和身体健康度的提高（0.89，[0.83，0.96]）。高度暗示性的增加受伤风险与增加精神工作量相关（1.07，[1.00，1.15]）。