Age and gender differences in linkages of sleep with subsequent mortality and health among very old Chinese.
BACKGROUND
Studies suggest that sleep quality and duration are significantly associated with mortality risk and health conditions, yet such studies are seldom conducted among very old adults. The objective of this study was to examine associations between self-reported sleep quality/duration and subsequent mortality/health among very old adults in China. A second objective determines whether these associations vary by age and gender.


METHODS
This study used data of the 2005 and 2008 waves from a large, representative survey with a total of 12,671 individuals in 22 provinces in mainland China, in which 3158 respondents were aged 90-99 and 2293 were centenarians. Two self-reported questions about sleep quality and duration were examined while adjusting for numerous socio-demographic, family/social support, health practices, and baseline health factors.


RESULTS
Hazard regressions showed that, when demographic factors are controlled for, Chinese elders who report poor and fair quality of sleep have 26% and 10% higher risk of death over the next three years compared to those with good sleep quality; those who sleep either 6h or less or 10h or more per day have an 18-22% higher mortality risk as compared to those who sleep 8h per day. The increased mortality risks of poorer sleep and too short or too long sleep duration are larger in men than in women and more robust in the oldest-old than in young elders. Logistic regressions show that poor sleep and daily sleep durations of 5h or less or 10h or more are also associated with worse health three years later.


CONCLUSIONS
Poorer sleep quality and too short or too long sleep duration are associated with higher subsequent mortality risk and lower odds of being in a healthy state among very old Chinese.
Department of Neurobiology, Duke University, Durham, NC 27710, USA.
Li
L
Qiu
Jessica
J
Sautter
Yuzhi
Y
Liu
Danan
D
Gu
D017677:Age Distribution; D000369:Aged, 80 and over / Q000706:statistics & numerical data*; D044466:Asian People / Q000706:statistics & numerical data*; D002681:China / Q000453:epidemiology; D005260:Female; D006306:Health Surveys / Q000706:statistics & numerical data*; D006801:Humans; D008136:Longevity; D008297:Male; D012307:Risk Factors; D017678:Sex Distribution; D012890:Sleep; D012893:Sleep Wake Disorders / Q000208:ethnology* / Q000401:mortality*