An analysis of shiftwork and self-reported depressive symptoms in a police cohort from Buffalo, New York.

Shiftwork has been associated with elevated depressive symptoms; police officers frequently work shifts and may experience depressive symptoms. This study assessed the association between depressive symptoms and shiftwork in a police cohort from Buffalo, New York, USA using a repeated cross-sectional design with data collected in 2004-2009 (n = 428) and 2010-2014 (n = 261). Electronic payroll records were used to quantitatively classify officers on the day, evening, or night shift based on the shift they spent most of their working hours. Two self-reported depressive symptomology measures were used as outcomes - the Center for Epidemiological Studies - Depression (CES-D) scale and the Beck Depression Inventory (BDI). Repeated measures linear and logistic regression analyses were used to estimate least squares means or odds, respectively, of depressive symptom questionnaire scores by shiftwork category. Those working the evening/night shift had higher odds for depressive symptoms according to the BDI (based on a cut-point score of 14) than those working the day shift (OR = 4.60, 95% CI = 1.15-18.39). Similar results were observed for the evening shift group. No differences in mean CES-D or BDI scores were observed between groups for short-term shiftwork, long-term shiftwork, or shift changes. After stratifying by stress, as measured by the Perceived Stress Scale (PSS), total Impact of Events (IES), and the Spielberger Police Stress Survey (SPSS), mean values for depressive symptoms were higher in the high-stress categories regardless of shiftwork status. Further research should include biomarkers for depression, a longitudinal study design with a larger cohort, and joint effects of shiftwork and stress on depressive symptoms.