Objective:The aim of this study was to identify atherosclerotic risk using pulse wave velocity (PWV) in steel workers employed in different shift-work rotations, and to elucidate its relationship to social jetlag and shift schedule details. Participants:Male workers in a steel factory (n = 77, 32 fast clockwise (CW), 30 slow counterclockwise (CC), 15 day workers (DW); mean age 42 ± SD 7.6 yrs) with at least 5 years experience in their current work schedule participated.Methods: All workers completed questionnaires on demographics, health, stimulants, sleep, social and work life, social jetlag (difference between mid-sleep time on workdays and days off used as a marker of circadian disruption) and chronotype (midsleep time on free days corrected for sleep deficit on workdays). In 63 workers we measured PWV, blood pressure (BP), heart rate (HR) between 08:00 and 12:30 h in controlled posture conditions (no caffeine/smoking/exercise).Results: There was no significant difference in PWV (covariates: age, BP) between the different shift-rotations (CW, CC and DW). In all workers combined HR and social jetlag were significantly positively correlated. Although demographic variables did not differ between shift-workers and day workers, the shift-workers (CW, CC) reported significantly more stomach upsets, digestion problems, weight fluctuations, 2 and social jetlag. The CW and CC workers did not differ in ratings of how shift-work affected sleep, social and work life. Conclusions:Although PWV was not different between the two shift-rotations, this pilot study shows first evidence that HR is related to social jetlag, and warrants more studies in different shift schedules.

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The current study investigated the accident rates across morning, late, and night shifts in rotating shift-workers employed in two different shift rotations at the same steel work factory. A retrospective analysis has been performed of accident data (N = 578) over a 5-year period (2003 through 2007) of 730 male shift-workers employed in either a clockwise (mean age of the workers 38.1 ± SD 9.8 years) or counterclockwise rotation (mean age 38.0 ± SD 10.1 years) with comparable work conditions. The overall accident rate across the 24-hour day was not significantly different between clockwise and counterclockwise shift rotation. In both shift-work rotations, morning shifts as opposed to night shifts exhibited a significantly higher accident rate.There was no significant difference between late shifts and morning or night shifts in either shift rotation. The increased accident rate in the morning shift at this steel factory could be related to the early starting time of the shift and to this shift being more labor intensive in both shift rotations. These findings suggest that work-related factors must be considered in addition to shift-work schedules when investigating accident rates in rotating shift-workers.