Sleep apnea and mortality in an aged cohort.

In the aged, sleep may be a vulnerable period for death from cardiovascular causes. Because of its high prevalence in the elderly, sleep apnea has been suggested to be one mechanism contributing to such sleep-related mortality. In this study, a cohort of 198 non-institutionalized elderly individuals (mean age at entry = 66) were followed for periods up to 12 years after initial polysomnography. The mortality ratio for sleep apnea (defined as a Respiratory Disturbance Index of over 10 events per sleep hour) was estimated to be 2.7 (95% CI = .95, 7.47). Multiple regression with the Cox proportional hazards model suggested that cardiovascular death was most clearly associated with age in this cohort. These results raise the possibility that "natural" death during sleep in the elderly may be associated with specific pathophysiological events during sleep.