Short sleep duration and smoking initiation in university students: a retrospective cohort study

Purpose The aim of this study was to clarify an association between short sleep duration and smoking initiation. Methods Participants eligible for this retrospective cohort study were university students who were admitted to a single national university in Japan between 2007 and 2015. Baseline sleep duration and smoking status were measured using general questionnaires at health checkups at admission. During a 6-year observation period, smoking initiation was assessed using general questionnaires at annual health checkups. Cox proportional hazards models adjusted for clinically relevant factors were used to assess the association between sleep duration and smoking initiation. Results Of 17,493 men, including 540, 5,568, 8,458, 2,507, and 420 men with sleep duration of