M Meloni1, A Del Rio, D Setzu, P Cocco. 1. Dipartimento di Sanità Pubblica, Sezione di Medicina del Lavoro, Università degli Studi di Cagliari, Asse didattico, Policlinico Universitario, Monserrato. melonim@medicina.unica.it
Abstract
BACKGROUND: Besides a significant deterioration in their family and personal life, shift workers also suffer health problems ranging from chronic fatigue to gastro-intestinal disorders, changes in sleep rhythm and cardiovascular disease, including arrhythmia and ischaemic heart disease. OBJECTIVES: The aim of the study was to assess the prevalence of electrocardiographic changes, such as conduction disorders, alterations in the repolarization phase and frequency-adjusted QT interval (QTc) in relation to shift work. METHODS: We conducted a cross sectional survey of 125 male subjects, 60 of whom worked fixed hours, and 65 were shift workers on two different schedules: 32 were on duty for 24 hours followed by 96 hours rest, and 33 worked 8-hour shifts (3 x 8). During periodical health assessment we examined their electrocardiograms (ECG), classified the morphology and measured the QTc interval. RESULTS: The QTc interval did not differ by type of work shift or by the presence of morphological changes in the ECG, including concurrent conduction disorders, or alterations in the repolarization phase. However, unlike day workers and 24-h shift workers, the QTc interval tended to increase with age among 8-h shift workers (r = 0.338; p = 0.05). Also, risk of conduction disorders was moderately, but not significantly, elevated among 8-h shift workers compared with subjects working fixed hours (OR = 1.9; I.E 95% 0.6, 5.7). CONCLUSIONS: Our study did not reveal significant changes in the ECG morphology in relation to the type of work shift.
BACKGROUND: Besides a significant deterioration in their family and personal life, shift workers also suffer health problems ranging from chronic fatigue to gastro-intestinal disorders, changes in sleep rhythm and cardiovascular disease, including arrhythmia and ischaemic heart disease. OBJECTIVES: The aim of the study was to assess the prevalence of electrocardiographic changes, such as conduction disorders, alterations in the repolarization phase and frequency-adjusted QT interval (QTc) in relation to shift work. METHODS: We conducted a cross sectional survey of 125 male subjects, 60 of whom worked fixed hours, and 65 were shift workers on two different schedules: 32 were on duty for 24 hours followed by 96 hours rest, and 33 worked 8-hour shifts (3 x 8). During periodical health assessment we examined their electrocardiograms (ECG), classified the morphology and measured the QTc interval. RESULTS: The QTc interval did not differ by type of work shift or by the presence of morphological changes in the ECG, including concurrent conduction disorders, or alterations in the repolarization phase. However, unlike day workers and 24-h shift workers, the QTc interval tended to increase with age among 8-h shift workers (r = 0.338; p = 0.05). Also, risk of conduction disorders was moderately, but not significantly, elevated among 8-h shift workers compared with subjects working fixed hours (OR = 1.9; I.E 95% 0.6, 5.7). CONCLUSIONS: Our study did not reveal significant changes in the ECG morphology in relation to the type of work shift.