Validation and Exploration of Sleep and Mood Predictors

To determine whether objectively recorded sleep durations were mortality risk factors, whether sleep duration could be distinguished from depression as a risk factor in Women's Health Initiative (WHI) data, and whether sleep-associated risks were attributable to specific pathophysiologic processes such as sleep apnea, circadian rhythm phase advances, or deficiencies of melatonin, or deficiencies of reproductive steroids. The study was ancillary to the WHI.