Soy Isoflavone Intake and Sleep Parameters over 5 Years among Chinese Adults: Longitudinal Analysis from the Jiangsu Nutrition Study

J Acad Nutr Diet. 2017 Apr;117(4):536-544.e2. doi: 10.1016/j.jand.2016.10.016. Epub 2016 Dec 10.

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.

Design: 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.

Participants/setting: 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).

Main outcome measures: We measured sleep duration in 2002 and 2007 and daytime falling asleep occurrence in 2007.

Statistical analyses performed: 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.

Keywords: Chinese adults; Daytime falling asleep; Long sleep duration; Longitudinal; Soy isoflavone.

MeSH terms

  • Adult
  • Anthropometry
  • Asian People*
  • China
  • Diet*
  • Dietary Carbohydrates / administration & dosage
  • Dietary Fats / administration & dosage
  • Dietary Proteins / administration & dosage
  • Energy Intake
  • Female
  • Follow-Up Studies
  • Glycine max / chemistry*
  • Humans
  • Isoflavones / administration & dosage*
  • Logistic Models
  • Longitudinal Studies
  • Male
  • Middle Aged
  • Nutrition Assessment
  • Prospective Studies
  • Sedentary Behavior
  • Sleep / physiology*
  • Surveys and Questionnaires

Substances

  • Dietary Carbohydrates
  • Dietary Fats
  • Dietary Proteins
  • Isoflavones