Mortality Associated With Sleep Duration and Insomnia

TLDR

Patients often complain of insufficient sleep or chronic insomnia, assuming they need 8 hours of sleep. The study aims to determine which sleep durations predict optimal survival and whether insomnia signals mortality risks, and to evaluate the need for further research on the risks of long sleep and sleeping‑pill use. The authors used Cox proportional hazards models on data from over 1.1 million participants aged 30–102, adjusting for demographics, habits, health factors, and medication use, to assess associations between sleep duration, insomnia, and mortality up to 1988. Analysis showed that 7 hours of sleep conferred the lowest mortality risk, while sleeping 8 or more hours or 6 or fewer hours increased risk (exceeding 15 % for >8.5 hours or <3.5–4.5 hours), insomnia was not linked to excess mortality, and sleeping‑pill use was associated with higher mortality, though causality remains unproven.

Abstract

Patients often complain about insufficient sleep or chronic insomnia in the belief that they need 8 hours of sleep. Treatment strategies may be guided by what sleep durations predict optimal survival and whether insomnia might signal mortality risks.In 1982, the Cancer Prevention Study II of the American Cancer Society asked participants about their sleep duration and frequency of insomnia. Cox proportional hazards survival models were computed to determine whether sleep duration or frequency of insomnia was associated with excess mortality up to 1988, controlling simultaneously for demographics, habits, health factors, and use of various medications.Participants were more than 1.1 million men and women from 30 to 102 years of age. The best survival was found among those who slept 7 hours per night. Participants who reported sleeping 8 hours or more experienced significantly increased mortality hazard, as did those who slept 6 hours or less. The increased risk exceeded 15% for those reporting more than 8.5 hours sleep or less than 3.5 or 4.5 hours. In contrast, reports of "insomnia" were not associated with excess mortality hazard. As previously described, prescription sleeping pill use was associated with significantly increased mortality after control for reported sleep durations and insomnia.Patients can be reassured that short sleep and insomnia seem associated with little risk distinct from comorbidities. Slight risks associated with 8 or more hours of sleep and sleeping pill use need further study. Causality is unproven.