title: Afternoon Napping and Cognition in Chinese Older Adults: Findings from the China Health and Retirement Longitudinal Study Baseline Assessment.
abstract: OBJECTIVE
  To examine the cross-sectional associations between self-reported postlunch napping and structured cognitive assessments in Chinese older adults.
  
  
  METHODS
  Cross-sectional cohort study.
  
  
  METHODS
  China.
  
  
  METHODS
  Individuals aged 65 and older from the baseline national wave of the China Health and Retirement Longitudinal Study (CHARLS) (N = 2,974).
  
  
  METHODS
  Interview-based cognitive assessments of orientation and attention, episodic memory, visuospatial abilities, and a combined global cognition score incorporating these assessments. Other self-reported or interview-based assessments included postlunch napping duration, nighttime sleep duration, demographic characteristics, health habits, comorbidities, functional status and social activities. According to reported napping duration, older adults were categorized as non-nappers (0 minutes), short nappers (<30 minutes), moderate nappers (30-90 minutes), and extended nappers (>90 minutes).
  
  
  RESULTS
  Postlunch napping was reporting in 57.7% of participants for a mean of 63 minutes. Cognitive function was significantly associated with napping (P < .001). Between-group comparisons showed that moderate nappers had better overall cognition than nonnappers (P < .001) or extended nappers (P = .01). Nonnappers also had significantly poorer cognition than short nappers (P = .03). In multiple regression analysis, moderate napping was significantly associated with better cognition than non- (P = .004), short (P = .04), and extended napping (P = .002), after controlling for demographic characteristics, body mass index, depression, instrumental activities of daily living, social activities, and nighttime sleep duration.
  
  
  CONCLUSIONS
  A cross-sectional association was found between moderate postlunch napping and better cognition in Chinese older adults. The cross-sectional design and self-reported measures of sleep limited the findings. Longitudinal studies with objective napping measures are needed to further test this hypothesis.
authors.affiliation: Center for Sleep and Circadian Neurobiology, Johns Hopkins University, Baltimore, Maryland.|School of Nursing, Johns Hopkins University, Baltimore, Maryland.
authors.forename: Junxin
authors.initials: J
authors.lastname: Li
authors.affiliation: School of Nursing, Johns Hopkins University, Baltimore, Maryland.
authors.forename: Pamela Z
authors.initials: PZ
authors.lastname: Cacchione
authors.affiliation: School of Nursing, Johns Hopkins University, Baltimore, Maryland.
authors.forename: Nancy
authors.initials: N
authors.lastname: Hodgson
authors.affiliation: School of Nursing, Johns Hopkins University, Baltimore, Maryland.
authors.forename: Barbara
authors.initials: B
authors.lastname: Riegel
authors.affiliation: Center for Sleep and Circadian Neurobiology, Johns Hopkins University, Baltimore, Maryland.
authors.forename: Brendan T
authors.initials: BT
authors.lastname: Keenan
authors.affiliation: Center for Sleep and Circadian Neurobiology, Johns Hopkins University, Baltimore, Maryland.
authors.forename: Mathew T
authors.initials: MT
authors.lastname: Scharf
authors.affiliation: School of Nursing, College of Health and Human Services, George Mason University, Fairfax, Virginia.
authors.forename: Kathy C
authors.initials: KC
authors.lastname: Richards
authors.affiliation: Center for Sleep and Circadian Neurobiology, Johns Hopkins University, Baltimore, Maryland.|Division of Geriatric Medicine, School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania.
authors.forename: Nalaka S
authors.initials: NS
authors.lastname: Gooneratne
mesh_terms: D000368:Aged; D002681:China; D003071:Cognition / Q000502:physiology*; D015331:Cohort Studies; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D008297:Male; D011939:Mental Recall; D009483:Neuropsychological Tests; D012044:Regression Analysis; D012146:Rest / Q000502:physiology*; D012189:Retrospective Studies; D012890:Sleep / Q000502:physiology*; D013997:Time Factors
keywords: cognition; older adults; postlunch napping; sleep duration