Sleep
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A population-based probability sample of elderly individuals (n = 426), who were originally studied between 1981 and 1986 (mean age at initial study was 72.5 years), were followed for mortality. Those with > or = 30 respiratory disturbances per hour of sleep had significantly shorter survival (p = 0.0034), but the respiratory disturbance index (RDI) was not an independent predictor of death. When Cox proportional hazards analysis was done, only age (the strongest predictor), cardiovascular disease and pulmonary disease were independent predictors of death. It may be that factors that are secondary to or associated with sleep-disordered breathing (SDB), such as cardiovascular or pulmonary disease, predispose these elderly to death.