Objective measures of circadian disruption are difficult to capture in a free-living environment hence the importance of validating subjective measures of jetlag. We aimed to assess the internal consistency of the 15-item Liverpool Jetlag Scale and its convergent and divergent validity with indicators of fatigue and anxiety in a large sample of air passengers. Online survey of passengers was conducted after travel on a range of long-haul flights. Jetlag was captured using the Liverpool scale, fatigue was measured using the Vitality subscale of the Short-Form Health Survey (SF-36), and the presence of anxiety or worry before, during, and after flight was self-reported. Inter-item correlations and Cronbach's alpha were calculated to assess the internal consistency of the scale. Exploratory factor analysis was used to examine whether the scale was consistent with one underlying construct of circadian disruption. Correlations between fatigue and anxiety (flying, situational, symptoms) with jetlag were used to assess convergent and divergent validity. Linear regression was used to determine the most important symptoms contributing to subjective jetlag rating. N = 460 passengers (57% female, mean age 50, SD 16 years) were surveyed. Cronbach's alpha indicated high internal reliability (alpha = 0.85). Jetlag was more strongly correlated with fatigue (rho = 0.47) than any type of anxiety (rho = 0.10-0.22). Exploratory factor analysis indicated responses were consistent with four factors: (i) fatigue/daytime impairment, (ii) sleep disturbance, (iii) changes in appetite and (iv) changes in bowel function. Regression analysis indicated that only changes in concentration, sleep time, fatigue, sleep quality and frequency of bowel motions were independent correlates of subjective jetlag (R2 = 27%). The Liverpool Jetlag Scale is internally consistent and demonstrates the expected relationships with fatigue and anxiety. Patterns of response are not consistent with all items being derived from one underlying factor, i.e. circadian disruption. Further, not all items contributed to the jetlag rating, suggesting the single-item rating may be useful for capturing the subjective experience of jetlag, whilst a total jetlag score is useful for also capturing circadian symptoms considered by passengers to be unrelated to jetlag. Validation of subjective jetlag against objective measures of circadian disruption is required.

中文翻译：

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利物浦时差问卷的内部一致性以及收敛性和发散性有效性。

在自由生活的环境中很难获得客观的昼夜节律测量，因此验证时差的主观测量非常重要。我们的目标是评估15个项目的利物浦时差量表的内部一致性以及其收敛性和发散性，并以大量航空乘客的疲劳和焦虑指标为指标。乘坐一系列长途航班旅行后，对乘客进行了在线调查。使用利物浦量表捕获时差，使用“简短健康调查”（SF-36）的“活力”子量表测量疲劳，并自动报告飞行前，飞行中和飞行后是否存在焦虑或忧虑。计算项目间的相关性和克朗巴赫（Cronbach）α，以评估量表的内部一致性。探索性因素分析用于检查量表是否与昼夜节律破坏的一种潜在结构一致。时差反应与疲劳和焦虑（飞行，处境，症状）之间的相关性用于评估收敛性和发散性有效性。线性回归用于确定导致主观时差评分最重要的症状。对N = 460名乘客（女性占57％，平均年龄50，标准差16岁）进行了调查。克朗巴赫（Cronbach）的alpha表示内部可靠性很高（alpha = 0.85）。与任何类型的焦虑（rho = 0.10-0.22）相比，时差与疲劳（rho = 0.47）的相关性更强。探索性因素分析表明，反应与四个因素一致：（i）疲劳/白天障碍，（ii）睡眠障碍，（iii）食欲改变和（iv）肠功能改变。回归分析表明，只有浓度，睡眠时间，疲劳，睡眠质量和排便频率的变化才是主观时差的独立相关因素（R2 = 27％）。利物浦时差量表在内部是一致的，并显示出与疲劳和焦虑的预期关系。响应方式与从一个潜在因素（即昼夜节律紊乱）得出的所有项目不一致。此外，并非所有项目都对时差评级有贡献，这表明单项评级可能有助于捕获时差的主观体验，而总时差得分也对捕获乘客认为与时差无关的昼夜节律症状有用。需要对照生物钟破坏的客观指标来验证主观时差。