Atherosclerotic risk and social jetlag in rotating shift-workers: First evidence from a pilot study

Abstract

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.

Strategies to decrease social jetlag: Reducing evening blue light advances sleep and melatonin

“…In previous studies, SJL (>2 hr) has been associated with a decline in academic performance (Haraszti, Ella, Gyöngyösi, Roenneberg, & Káldi, ) and with several health issues, such as increased risk for cigarettes and alcohol consumption, overweight, cardiovascular risk, diabetes and depression (Kantermann et al., ; Koopman et al., ; Larcher et al., ; Levandovski et al., ; Mota, Silva, Balieiro, Fahmy, & Crispim, ; Roenneberg, Allebrandt, Merrow, & Vetter, ; Rutters et al., ; Wittmann et al., ; Wong, Hasler, Kamarck, Muldoon, & Manuck, ). Here, we sought to reduce SJL through practical interventions using light, given that light is the strongest zeitgeber for human behavioural entrainment (Duffy & Wright, ; Roenneberg & Foster, ; Roenneberg & Merrow, ).…”

Circadian phase, circadian period and chronotype are reproducible over months

“…In addition, light allows for activities like work or food consumption at the times for natural sleep, which is circadian misalignment and conflicts with a healthy lifestyle (Roenneberg et al, 2012; Wittmann et al, 2006). One prominent example thereof is shift work, which is associated with negative sleep and health outcomes (Akerstedt et al, 1984; Folkard et al, 2005; Gold et al, 1992; Kantermann et al, 2013; Kantermann et al, 2014; Knutsson, 2003; Lunn et al, 2017; Smith & Eastman, 2012). …”

“…There is evidence that sleep time individuality moderates the impact of shift work on sleep. For example, individuals with a habitual late sleep behavior have been shown to be more suitable for night work compared to individuals with a habitual early sleep behavior, quantified by the difference in the amount of their social jetlag (Fischer et al, 2016; Kantermann et al, 2013; Vetter et al, 2015). Applying chronobiology to the practice can help reduce the sleep and health burden in many shift workers (Boivin & James, 2005; Eastman, 2016; Kantermann et al, 2012; Smith & Eastman, 2012).…”

“…Hence, a better understanding of the variability of these parameters in healthy individuals is needed (Goel, 2016; Van Reen et al, 2013). This will also help to better understand phenomena like circadian misalignment and social jetlag, which have, for example, been associated with adverse lifestyle habits (Wittmann et al, 2006), cardiovascular problems in shift workers (Kantermann et al, 2013) and increased rates of obesity (Roenneberg et al, 2012). …”

Turnos de trabajo: ¿un factor de riesgo cardiovascular?

“…Del total de los artículos revisados, ocho tenían grupo control 14,15,[18][19][20][22][23][24] que generalmente fueron reclutados de diferentes secciones de la misma organización y seis estaban ajustados por factores de confusión 14,15,[18][19][20]22 : edad, sexo, experiencia de trabajo por turnos, los factores de estilo de vida, o el contenido del trabajo. La mayoría de los estudios se realizaron en poblaciones relativamente homogéneas (por ej enfermeras, controladores aéreos, etc), pero ninguno presenta resultados diferenciados por edades y solamente uno por nivel socioeconómico 19 .…”