Separate and joint associations of shiftwork and sleep quality with lipids

Background: Shift work and/or sleep quality may affect health. We investigated whether shift work and sleep quality, separately and jointly, were associated with abnormal levels of triglycerides, total cholesterol (TC), and low-and high-density lipoprotein cholesterol in 360 police officers (27.5% women). Methods: Triglycerides, TC, and high-density lipoprotein were analyzed on the Abbott Architect; low-density lipoprotein was calculated. Shift work was assessed using City of Buffalo payroll work history records. Sleep quality (good, <= 5; intermediate, 6-8; poor, >= 9) was assessed using the Pittsburgh Sleep Quality Index questionnaire. A shift work + sleep quality variable was created: day plus good sleep; day plus poor sleep; afternoon/night plus good; and poor sleep quality. Mean values of lipid biomarkers were compared across categories of the exposures using analysis of variance/analysis of covariance. Results: Shift work was not significantly associated with lipids. However, as sleep quality worsened, mean levels of triglycerides and TC gradually increased but only among female officers (age-and raceadjusted p = 0.013 and 0.030, respectively). Age significantly modified the association between sleep quality and TC. Among officers >= 40 years old, those reporting poor sleep quality had a significantly higher mean level of TC (202.9 +/- 3.7 mg/dL) compared with those reporting good sleep quality (190.6 +/- 4.0 mg/dL) (gender-and race-adjusted p = 0.010). Female officers who worked the day shift and also reported good sleep quality had the lowest mean level of TC compared with women in the other three categories (p = 0.014). Conclusion: Sleep quality and its combined influence with shift work may play a role in the alteration of some lipid measures. (C) 2015, Occupational Safety and Health Research Institute. Published by Elsevier.