title: Circadian Misalignment Increases C-Reactive Protein and Blood Pressure in Chronic Shift Workers.
abstract: Shift work is a risk factor for inflammation, hypertension, and cardiovascular disease. This increased risk cannot be fully explained by classical risk factors. Shift workers' behavioral and environmental cycles are typically misaligned relative to their endogenous circadian system. However, there is little information on the impact of acute circadian misalignment on cardiovascular disease risk in shift workers, independent of differences in work stress, food quality, and other factors that are likely to differ between night and day shifts. Thus, our objectives were to determine the independent effect of circadian misalignment on 24-h high-sensitivity C-reactive protein (hs-CRP; a marker of systemic inflammation) and blood pressure levels-cardiovascular disease risk factors-in chronic shift workers. Chronic shift workers undertook two 3-day laboratory protocols that simulated night work, comprising 12-hour inverted behavioral and environmental cycles (circadian misalignment) or simulated day work (circadian alignment), using a randomized, crossover design. Circadian misalignment increased 24-h hs-CRP by 11% ( p < 0.0001). Circadian misalignment increased 24-h systolic blood pressure (SBP) and diastolic blood pressure (DBP) by 1.4 mmHg and 0.8 mmHg, respectively (both p ≤ 0.038). The misalignment-mediated increase in 24-h SBP was primarily explained by an increase in SBP during the wake period (+1.7 mmHg; p = 0.017), whereas the misalignment-mediated increase in 24-h DBP was primarily explained by an increase in DBP during the sleep opportunity (+1.8 mmHg; p = 0.005). Circadian misalignment per se increases hs-CRP and blood pressure in shift workers. This may help explain the increased inflammation, hypertension, and cardiovascular disease risk in shift workers.
authors.affiliation: Medical Chronobiology Program, Division of Sleep and Circadian Disorders, Departments of Medicine and Neurology, Brigham and Women's Hospital, Boston, Massachusetts.|Division of Sleep Medicine, Department of Medicine, Harvard Medical School, Boston, Massachusetts.
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Morris
authors.affiliation: Medical Chronobiology Program, Division of Sleep and Circadian Disorders, Departments of Medicine and Neurology, Brigham and Women's Hospital, Boston, Massachusetts.
authors.forename: Taylor E
authors.initials: TE
authors.lastname: Purvis
authors.affiliation: Medical Chronobiology Program, Division of Sleep and Circadian Disorders, Departments of Medicine and Neurology, Brigham and Women's Hospital, Boston, Massachusetts.
authors.forename: Joseph
authors.initials: J
authors.lastname: Mistretta
authors.affiliation: Medical Chronobiology Program, Division of Sleep and Circadian Disorders, Departments of Medicine and Neurology, Brigham and Women's Hospital, Boston, Massachusetts.|Division of Sleep Medicine, Department of Medicine, Harvard Medical School, Boston, Massachusetts.
authors.forename: Kun
authors.initials: K
authors.lastname: Hu
authors.affiliation: Medical Chronobiology Program, Division of Sleep and Circadian Disorders, Departments of Medicine and Neurology, Brigham and Women's Hospital, Boston, Massachusetts.|Division of Sleep Medicine, Department of Medicine, Harvard Medical School, Boston, Massachusetts.
authors.forename: Frank A J L
authors.initials: FAJL
authors.lastname: Scheer
mesh_terms: D000328:Adult; D015415:Biomarkers; D001794:Blood Pressure; D002097:C-Reactive Protein / Q000032:analysis*; D002318:Cardiovascular Diseases / Q000209:etiology; D021081:Chronobiology Disorders / Q000150:complications* / Q000503:physiopathology; D002940:Circadian Rhythm / Q000502:physiology*; D005260:Female; D006801:Humans; D006973:Hypertension / Q000209:etiology* / Q000503:physiopathology; D007249:Inflammation / Q000209:etiology; D008297:Male; D008875:Middle Aged; D012307:Risk Factors; D000073577:Shift Work Schedule; D012890:Sleep; D014940:Work Schedule Tolerance / Q000502:physiology*; D055815:Young Adult
chemical_list: D015415:Biomarkers; D002097:C-Reactive Protein
keywords: circadian misalignment; hypertension; inflammatory markers; night work; shift work