Sleep Disturbances and Cause-Specific Mortality: Results From the GAZEL Cohort Study

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 < 1% loss to follow-up. Body mass index, hypertension, and diabetes were measured annually through self-reporting. During follow-up, a total of 1,045 men and women died. Sleep disturbances were associated with a higher overall mortality risk in men (P = 0.005) but not in women (P = 0.33). This effect was most pronounced for men < 45 years of age (>= 3 symptoms vs. none: hazard ratio = 2.03, 95% confidence interval: 1.24, 3.33). There were no clear associations between sleep disturbances and cardiovascular mortality rates, although men and women with sleep disturbances were more likely to develop hypertension and diabetes (P < 0.001). Compared with people with no sleep disturbances, men who reported >= 3 types of sleep disturbance had an almost 5 times' higher risk of committing suicide (hazard ratio = 4.99, 95% confidence interval: 1.59, 15.7). Future strategies to prevent premature deaths may benefit from assessment of sleep disturbances, especially in younger individuals.