title: Association between habitual daytime napping and metabolic syndrome: a population-based study.
abstract: OBJECTIVE
  Our objective was to evaluate the association between habitual daytime napping and the prevalence of metabolic syndrome.
  
  
  METHODS
  We conducted a population-based study of 8,547 subjects aged 40 years or older. Metabolic syndrome was defined according to a harmonized definition from a joint statement and the recommended thresholds for the Chinese population. Information about sleep duration was self-reported.
  
  
  RESULTS
  The prevalence of metabolic syndrome in the no daytime napping group, the 0 to 1 hour daytime napping group and the more than 1 hour daytime napping group were 35.0%, 36.0% and 44.5% among the females (P<0.0001). Increased daytime napping hours were positively associated with parameters of metabolic syndrome in the female subjects, including waist circumference, systolic blood pressure, triglycerides and fasting plasma glucose (P<0.05 for all). Multivariate adjusted logistic regression analysis revealed that, compared to the no habitual daytime napping females, napping for more than 1 hour was independently associated with an increased prevalence of metabolic syndrome (odds ratio 1.39, 95% confidence interval, 1.13-1.72). Compared to the female subjects in the no daytime napping group, those habitually napped for more than 1 hour exhibited 46% and 26% increases in the prevalence of central obesity and hypertriglyceridemia (all P<0.05). No statistically significant associations were detected between daytime napping hours and metabolic syndrome among the male subjects.
  
  
  CONCLUSIONS
  Daytime napping is associated with an increased prevalence of metabolic syndrome in middle-aged non-obese Chinese women.
authors.affiliation: Department of Endocrinology, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, 107 Yanjiang West Road, Guangzhou 510120, People's Republic of China.
authors.forename: Diaozhu
authors.initials: D
authors.lastname: Lin
authors.affiliation: Department of Endocrinology, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, 107 Yanjiang West Road, Guangzhou 510120, People's Republic of China.
authors.forename: Kan
authors.initials: K
authors.lastname: Sun
authors.affiliation: Department of Endocrinology, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, 107 Yanjiang West Road, Guangzhou 510120, People's Republic of China.
authors.forename: Feng
authors.initials: F
authors.lastname: Li
authors.affiliation: Department of Endocrinology, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, 107 Yanjiang West Road, Guangzhou 510120, People's Republic of China.
authors.forename: Yiqin
authors.initials: Y
authors.lastname: Qi
authors.affiliation: Department of Endocrinology, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, 107 Yanjiang West Road, Guangzhou 510120, People's Republic of China.
authors.forename: Meng
authors.initials: M
authors.lastname: Ren
authors.affiliation: Department of Endocrinology, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, 107 Yanjiang West Road, Guangzhou 510120, People's Republic of China.
authors.forename: Chulin
authors.initials: C
authors.lastname: Huang
authors.affiliation: Department of Endocrinology, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, 107 Yanjiang West Road, Guangzhou 510120, People's Republic of China.
authors.forename: Juying
authors.initials: J
authors.lastname: Tang
authors.affiliation: Department of Endocrinology, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, 107 Yanjiang West Road, Guangzhou 510120, People's Republic of China.
authors.forename: Shengneng
authors.initials: S
authors.lastname: Xue
authors.affiliation: Department of Endocrinology, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, 107 Yanjiang West Road, Guangzhou 510120, People's Republic of China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Li
authors.affiliation: Department of Endocrinology, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, 107 Yanjiang West Road, Guangzhou 510120, People's Republic of China. Electronic address: hfxyl@163.net.
authors.forename: Li
authors.initials: L
authors.lastname: Yan
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000886:Anthropometry; D002681:China / Q000453:epidemiology; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D008297:Male; D024821:Metabolic Syndrome / Q000453:epidemiology* / Q000503:physiopathology*; D008875:Middle Aged; D015995:Prevalence; D012727:Sex Characteristics; D012890:Sleep; D012959:Socioeconomic Factors
keywords: Daytime napping; Metabolic syndrome; Night sleeping; Siesta; Sleep