Background and Objectives:Lung cancer is the most common cancer and cancer related cause of death worldwide.However,the association between sleep duration and incident lung cancer has not been investigated in a prospective cohort study.Methods:We prospectively examined the association between sleep duration and incident lung cancer in a cohort of 21,026 United States(US)male physicians.Self-reported sleep duration was ascertained during 2002 annual follow-up questionnaire.Incident lung cancer was ascertained through yearly follow-up questionnaires.Cox regression was used to estimate relative risk of incident lung cancer.Results:The average age at baseline was 68.3±8.8 yr.During a mean follow up of 7.5(±2.2)yr,150 cases of lung cancer occurred.Using 7 h of sleep as the reference group,multivariable adjusted hazard ratios(95%CI)for lung cancer were 1.18(0.77-1.82),1.0(ref),and 0.97(0.67-1.41)from lowest to the highest category of sleep duration(P for quadratic trend 0.697),respectively.In a secondary analysis,smoking status did not modify the sleep duration-lung cancer association(P=0.78).There was no evidence for an interaction between sleep duration and sleep apnea on the risk of lung cancer either(P=0.65).Conclusions:Our data failed to show a higher risk of lung cancer in association with altered sleep duration among US male physicians. Background and Objectives:Lung cancer is the most common cancer and cancer related cause of death worldwide.However,the association between sleep duration and incident lung cancer has not been investigated in a prospective cohort study.Methods:We prospectively examined the association between sleep duration And incident lung cancer in a cohort of 21,026 United States(US) male physicians.Self-reported sleep duration was ascertained during 2002 annual follow-up questionnaire.Incident lung cancer was ascertained through several yearly follow-up questionnaires.Cox regression was used to estimate Relative risk of incident lung cancer.Results:The average age at baseline was 68.3±8.8 yr. During a mean follow up of 7.5(±2.2)yr,150 cases of lung cancer occurred.Using 7 h of sleep as the reference group, Multivariable adjusted hazard ratios(95%CI) for lung cancer were 1.18(0.77-1.82),1.0(ref),and 0.97(0.67-1.41) from lowest to the highest category of sleep duration(P for quadratic trend 0.697),respectively .In a secondary analysis, smoking status did not modify the sleep duration-lung cancer association(P=0.78).There was no evidence for an interaction between sleep duration and sleep apnea on the risk of lung cancer either(P=0.65). Conclusions: Our data failed to show a higher risk of lung cancer in association with altered sleep duration among US male physicians.