0380 Association of Day-to-Day Variability in Rest-Activity Circadian Rhythm with Sleep Quality Among Law Enforcement Officers

Abstract Introduction Poor sleep quality may be attributed to several occupational factors and has been linked to adverse health outcomes, including cardiovascular disease. Recent epidemiologic studies suggest rest-activity circadian rhythm (RAR) as a possible determinant of poor sleep quality. The focus of these studies has been on the magnitude of the parameters of RAR with little attention to the impact of their day-to-day fluctuation. We examined association of daily variation in parameters of RAR with sleep quality. Methods Participants (n=280) were officers from the Buffalo Cardio-metabolic Occupational Police Stress Study (2004-2009). Sleep quality was determined using the Pittsburgh Sleep Quality Index (PSQI). Participants wore wrist actigraph for a minimum of seven days. A cosine curve was fit to measure goodness of fit and estimate the mean values of the three parameters of RAR: Mesor, Amplitude, and Acrophase. Day-to-day variability of the parameters were assessed by fitting the cosine function separately for each day and computing the sample standard deviation across the days. Poisson regression models were conducted adjusting for demographic, lifestyle, and occupational factors. Results The prevalence of poor sleep quality was 50.3%. Poor sleep quality was 56% higher in officers with the largest day-to-day variability in Mesor (PR=1.56, 95%CI:1.11 - 2.19) compared to those with the lowest daily variation. Similar estimates were found for Amplitude (PR=1.42, 1.03 - 1.95), Acrophase (PR=1.86, 1.29 - 2.67), and measure of goodness of fit (PR=1.54, 1.13 - 2.11). On the other hand, mean values of RAR parameters were not significantly associated with poor sleep quality. Conclusion Results suggest larger daily variation in parameters of RAR is associated with a decrease in sleep quality. Given that day-to-day variation in RAR may increase the odds of poor sleep quality, future studies ought to address risk factors for higher daily fluctuations in RAR which could aid in developing intervention measures. Support CDC/NIOSH grant 1R01OH009640-01A1