Association between Work-Related Stress and QT Prolongation in Male Workers

Abstract

Background: Work-related stress is a potential cardiovascular risk factor, but the underlying mechanism is not fully explained. The autonomic nervous system control of cardiac function might play a specific role; therefore, monitoring the QT interval in the electrocardiogram can highlight an autonomic imbalance induced by occupational stressors. The aim of our study was to explore the QT interval parameters as early indicators of imbalance of the autonomic cardiac function in relation to work-related stress. Methods: During 2015–2016 annual workplace health surveillance, we measured work-related stress in 484 workers of a logistic support company using the Health and Safety Executive (HSE) tool. We assessed the frequency-corrected QT (QTc) interval and the QT index (QTi) on the electrocardiogram of each participant, and collected demographic and clinical data. We compared the QTc values by the four Karasek’s categories (active/passive jobs, low/high strain job), and by job support (present/lacking), and conducted multivariate analysis to adjust for possible confounders. Results: The results of the multivariate regression analysis showed that QTc was prolonged among workers operating at a specific site where stress level was found to be elevated. Regular physical activity showed a beneficial effect against QTc prolongation. We did not observe an effect on QTc length by the cross-combined Karasek’s categories of job control, job demand, and job support. Conclusions: Our study suggests subclinical effects of conditions associated with work-related stress on the autonomic regulation of cardiac function. Further research is warranted to elucidate the combined effect of work organization and lifestyle factors on autonomic cardiac function.

Reply to Comment on Lecca, L.I.; Portoghese, I.; Mucci, N.; Galletta, M.; Meloni, F.; Pilia, I.; Marcias, G.; Fabbri, D.; Fostinelli, J.; Lucchini, R.G.; Cocco, P.; Campagna, M. Association between Work-Related Stress and QT Prolongation in Male Workers

“…We appreciate the interest raised by our paper on the association between conditions linked to work-related stress and the prolongation of the QT interval on the electrocardiogram [1]. Alizargar et al, in their commentary [2], raise two main concerns, namely: (1) the operational location would be the main determinant of QT interval prolongation, and (2) one would have to assess Pearson's correlation "before analyzing the assumptions that should be made before such an analysis".…”

“…Table 1. Test for the assumption of normality of the distribution of the continuous variables presented in Table 2 of Lecca et al (1). BMI-body mass index; KS-Kolmogorov-Smirnov; SD-standard deviation.…”

Comment on Lecca, L.I.; Portoghese, I.; Mucci, N.; Galletta, M.; Meloni, F.; Pilia, I.; Marcias, G.; Fabbri, D.; Fostinelli, J.; Lucchini, R.G.; Cocco, P.; Campagna, M. Association between Work-Related Stress and QT Prolongation in Male Workers. Int. J. Environ. Res. Public Health 2019, 16, 4781

“…We read with interest the article by Lecca et al [1], in which the authors focused on the effects of work-related stress on changes in the QT interval in the routine electrocardiogram (ECG) among workers without overt cardiovascular dysfunction. They also tried to consider some confounders in their analysis.…”

“…However, the main factor is age. Lecca et al [1] had excluded the people that had some of the these conditions so they could not interfere with the conclusion of their study. They also showed that the observed effects of age in the correlation analysis disappeared when they controlled for some factors, such as operating location, physical activity, systolic blood pressure (SBP), age, education, and alcohol intake; yet, they concluded that "age was a clear contributing factor in QTc and QTi prolongation in our study", and compared their results to other studies.…”

“…If both variables are normally and if the normality assumption is not met, distributed a Pearson's correlation and a Spearman's correlation analysis, respectively, are appropriate [3]. Lecca et al [1] provided no information about the normality of the variables, and it is very possible that some of their variables were not normally distributed, yet they performed a Pearson's correlation on them.…”