title: U-shaped relationships between sleep duration and metabolic syndrome and metabolic syndrome components in males: a prospective cohort study.
abstract: OBJECTIVE
  Based on cross-sectional studies, sleep duration has been shown to have a relationship with the prevalence of metabolic syndrome (MS); however, no prospective studies have verified a correlation between the incidence of MS and the gender difference. Herein we prospectively determined the association between MS and gender using a large sample.
  
  
  METHODS
  A total of 4774 subjects without MS, 30-65 years of age, participated in this study. One-way ANOVA and Chi-square test were used to analyze the baseline variables. Cox regression models were performed separately in a mixed-gender population, males and females, while controlling for lifestyle and sleep-related factors.
  
  
  RESULTS
  During an average of 4.4-year follow-up, 1506 subjects developed MS. Both short (<6 h) and long sleep durations (8-9 and ≥9 h) increased the incidence of MS and elevated the fasting blood glucose (FBG) level in the mixed-gender population (MS: HR = 1.43, 1.25, and 1.45, respectively; elevated FBG: HR = 1.61, 1.65, and 1.98, respectively) and males (MS: HR = 1.87, 1.73, and 1.96, respectively; elevated FBG: HR = 2.27, 2.28, and 3.16, respectively). The HR(8-9 and ≥9 h) for hypertriglyceridemia in males was 1.48 and 19.4, and the HR(<6, 6-7, and ≥9 h) for hypertension in females was 1.25, 1.46, and 1.72, respectively.
  
  
  CONCLUSIONS
  Both short and long sleep durations were associated with a greater incidence of MS and elevated FBG in a mixed-gender population and in males, and hypertension in females. Males who sleep longer were also at a higher risk for hypertriglyceridemia.
authors.affiliation: Department of Nutrition and Food Hygiene, College of Public Health, Harbin Medical University, Harbin, China.
authors.forename: Xue
authors.initials: X
authors.lastname: Li
authors.affiliation: Department of Nutrition and Food Hygiene, College of Public Health, Harbin Medical University, Harbin, China.
authors.forename: Liqun
authors.initials: L
authors.lastname: Lin
authors.affiliation: Department of Nutrition and Food Hygiene, College of Public Health, Harbin Medical University, Harbin, China.
authors.forename: Lin
authors.initials: L
authors.lastname: Lv
authors.affiliation: Department of Nutrition and Food Hygiene, College of Public Health, Harbin Medical University, Harbin, China.
authors.forename: Xiuyu
authors.initials: X
authors.lastname: Pang
authors.affiliation: Department of Nutrition and Food Hygiene, College of Public Health, Harbin Medical University, Harbin, China.
authors.forename: Shanshan
authors.initials: S
authors.lastname: Du
authors.affiliation: Department of Nutrition and Food Hygiene, College of Public Health, Harbin Medical University, Harbin, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Zhang
authors.affiliation: Department of Nutrition and Food Hygiene, College of Public Health, Harbin Medical University, Harbin, China.
authors.forename: Guanqiong
authors.initials: G
authors.lastname: Na
authors.affiliation: Department of Nutrition and Food Hygiene, College of Public Health, Harbin Medical University, Harbin, China.
authors.forename: Hao
authors.initials: H
authors.lastname: Ma
authors.affiliation: Department of Nutrition and Food Hygiene, College of Public Health, Harbin Medical University, Harbin, China.
authors.forename: Qiao
authors.initials: Q
authors.lastname: Zhang
authors.affiliation: Department of Nutrition and Food Hygiene, College of Public Health, Harbin Medical University, Harbin, China.
authors.forename: Shuo
authors.initials: S
authors.lastname: Jiang
authors.affiliation: Department of Nutrition and Food Hygiene, College of Public Health, Harbin Medical University, Harbin, China.
authors.forename: Haoyuan
authors.initials: H
authors.lastname: Deng
authors.affiliation: Department of Nutrition and Food Hygiene, College of Public Health, Harbin Medical University, Harbin, China.
authors.forename: Tianshu
authors.initials: T
authors.lastname: Han
authors.affiliation: Department of Nutrition and Food Hygiene, College of Public Health, Harbin Medical University, Harbin, China.
authors.forename: Changhao
authors.initials: C
authors.lastname: Sun
authors.affiliation: Department of Nutrition and Food Hygiene, College of Public Health, Harbin Medical University, Harbin, China. Electronic address: liying_helen@163.com.
authors.forename: Ying
authors.initials: Y
authors.lastname: Li
mesh_terms: D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D006943:Hyperglycemia / Q000209:etiology; D006973:Hypertension / Q000209:etiology; D015228:Hypertriglyceridemia / Q000209:etiology; D008297:Male; D024821:Metabolic Syndrome / Q000209:etiology*; D008875:Middle Aged; D011446:Prospective Studies; D012307:Risk Factors; D012737:Sex Factors; D012890:Sleep / Q000502:physiology*; D012892:Sleep Deprivation / Q000150:complications; D013997:Time Factors
keywords: Cohort study; Metabolic syndrome; Metabolic syndrome components; Sleep duration