Poor sleep is an increasing problem in modern society, but most previous studies on the association between sleep and mortality rates have addressed only duration, not quality, of sleep. The authors prospectively examined the effects of sleep disturbances on mortality rates and on important risk factors for mortality, such as body mass index, hypertension, and diabetes. A total of 16,989 participants in the GAZEL cohort study were asked validated questions on sleep disturbances in 1990 and were followed up until 2009, with