title: Soy Isoflavone Intake and Sleep Parameters over 5 Years among Chinese Adults: Longitudinal Analysis from the Jiangsu Nutrition Study.
abstract: BACKGROUND
  Soy isoflavone is beneficial for menopausal/postmenopausal symptoms, including sleep complaints. However, little is known about its longitudinal association with sleep in the general population.
  
  
  OBJECTIVE
  Our aim was to investigate the association between soy isoflavone intake and sleep duration and daytime falling asleep among Chinese adults.
  
  
  METHODS
  A longitudinal analysis was performed. Soy isoflavone intake was assessed by food frequency questionnaire. Sleep duration was self-reported at two time points. Occurrence of daytime falling asleep was determined at follow-up. Short and long sleep were defined as sleep <7 h/day or ≥9 h/day, respectively.
  
  
  METHODS
  Adults aged 20 years and older from the Jiangsu Nutrition Study (2002-2007) with complete isoflavone intake and sleep duration data at both time points (n=1,474) were analyzed (follow-up, n=1,492).
  
  
  METHODS
  We measured sleep duration in 2002 and 2007 and daytime falling asleep occurrence in 2007.
  
  
  METHODS
  Mixed-effects logistic regression was performed for repeated measures between isoflavone intake and sleep duration. Logistic regression was performed for daytime falling asleep at follow-up. Demographic, anthropometric, and social factors were adjusted in the analyses.
  
  
  RESULTS
  The prevalence of long sleep duration was 18.9% in 2002 and 12.6% in 2007, and the prevalence of daytime falling asleep was 5.3%. Compared with the lowest quartile of isoflavone intake, the highest quartile was associated with a lower risk of long sleep duration (odds ratio=0.66; 95% CI 0.48 to 0.90; P for trend=0.018) over 5 years. Compared with persistent low intake of isoflavone (less than median intake of isoflavone at two time points), persistent high intake was associated with a reduced risk of daytime falling asleep in women (odds ratio=0.20; 95% CI 0.06 to 0.68), but not men. No consistent association between soy isoflavone intake and short sleep duration was found.
  
  
  CONCLUSIONS
  Soy isoflavone intake was associated with a low risk of long sleep duration in both sexes and a low risk of daytime falling asleep in women but not men.
authors.forename: Yingting
authors.initials: Y
authors.lastname: Cao
authors.forename: Anne W
authors.initials: AW
authors.lastname: Taylor
authors.forename: Shiqi
authors.initials: S
authors.lastname: Zhen
authors.forename: Robert
authors.initials: R
authors.lastname: Adams
authors.forename: Sarah
authors.initials: S
authors.lastname: Appleton
authors.forename: Zumin
authors.initials: Z
authors.lastname: Shi
mesh_terms: D000328:Adult; D000886:Anthropometry; D044466:Asian People; D002681:China; D004032:Diet; D004040:Dietary Carbohydrates / Q000008:administration & dosage; D004041:Dietary Fats / Q000008:administration & dosage; D004044:Dietary Proteins / Q000008:administration & dosage; D002149:Energy Intake; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007529:Isoflavones / Q000008:administration & dosage*; D016015:Logistic Models; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D015596:Nutrition Assessment; D011446:Prospective Studies; D057185:Sedentary Behavior; D012890:Sleep / Q000502:physiology*; D013025:Glycine max / Q000737:chemistry*; D011795:Surveys and Questionnaires
chemical_list: D004040:Dietary Carbohydrates; D004041:Dietary Fats; D004044:Dietary Proteins; D007529:Isoflavones
keywords: Chinese adults; Daytime falling asleep; Long sleep duration; Longitudinal; Soy isoflavone