Background: Compared to day workers, shift workers face an elevated risk of cardiovascular disease. We reviewed the evidence to address the research question: Does acute exposure to shift work impact (blunt) the natural drop (dip) in Blood Pressure (BP) occurring during sleep and/or nighttime hours? (PROSPERO CRD42018110847).
Methods: We performed a systematic review of five databases. We compared pooled estimates of mean BP stratified by periods of shift work, rest/leisure, and sleep, and evaluated the quality of evidence with the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) framework.
Results: Our search covered 1/1/1980-10/24/2018 and yielded 1,636 records. Inter-rater agreement during screening was high (Kappa=0.87). We retained 44 studies described in 50 publications. We identified wide variation in shift worker type, shift schedules, and regularity of BP measurements. Most studies examined BP during one shift workday and one rest/leisure day. No study examined the impact of repeated exposure to shift work on the sleep-related dip in BP. Eighteen studies examined night shifts and one reported on BP during sleep post night shift. Compared to BP measured during shift work, BP measured during any sleep period separate from shift work was lower by 17.5 mmHg Systolic BP (95%CI 15.75, 19.27) and 15.4 mmHg lower for Diastolic BP (95%CI 14.38, 16.42) (p < 0.05).
Conclusions: There is limited research exploring the acute and long-term impact of shift work on BP during sleep. The available evidence is heterogenous, low quality, and suggests that the mean dip in BP during sleep separate from shift work is not blunted.
Keywords: Blood pressure; Meta-analysis; Shift work; Sleep; Systematic review.
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