Sleep Duration and Mortality

I read the paper by Khan et al1 with great interest. The authors conducted a long-term survival study to evaluate the relationship between self-reported sleep duration and risk of fatal coronary heart disease, sudden cardiac death, cancer related death and all-cause mortality. Adjusted hazard ratios (HRs) (95% confidence intervals (CIs)) of long sleep duration (> 10 hours) against sleep duration under 8 hours was 1.19 (1.01-1.43) for all-cause mortality, 1.27 (0.88-1.84) for fatal coronary heart disease, 1.20 (0.78-1.86) for sudden cardiac death, and 1.29 (0.92-1.80) for cancer death, respectively.