RT Journal
A1 Kripke DF, Garfinkel L, Wingard DL, Klauber MR, Marler MR
T1 MOrtality associated with sleep duration and insomnia
JF Archives of General Psychiatry
JO Archives of General Psychiatry
YR 2002
FD February 1
VO 59
IS 2
SP 131
OP 136
DO 10.1001/archpsyc.59.2.131
UL http://dx.doi.org/10.1001/archpsyc.59.2.131
AB Background 
    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.Methods 
    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.Results 
    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 than3.5 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.Conclusions 
    Patients can be reassured that short sleep and insomnia seem associated with little risk distinct from comorbidities. Slight risks associated with8 or more hours of sleep and sleeping pill use need further study. Causality is unproven.