Sleep duration and risk of lung cancer in the physicians' health study.

BACKGROUND

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.