Sleep duration is related to increased mortality risk through white blood cell counts in a large national sample.

This large, cross-sectional analysis suggests that sleep duration is associated with changes in mortality risk through-in part-effects on leukocyte count. These findings support an immunological/inflammatory pathway linking sleep and mortality. Further research in populations with quantitatively different sleep patterns can determine whether this sleep-immune-mortality pathway is restricted to Western, industrial samples or is characteristic of humans in general.