title: Interaction between physical activity and sleep duration in relation to insulin resistance among non-diabetic Chinese adults.
abstract: BACKGROUND
  It is of a public health interest to explore the relationship between different types of physical activity, sleep duration and diabetes/insulin resistance. However, little is known about such relationship. This study examines the single and joint associations of different types of physical activity, and sleep duration on insulin resistance among non-diabetic Chinese adults.
  
  
  METHODS
  Data was collected from 1124 non-diabetic adults in Jiangsu Province from the China Health and Nutrition Survey (CHNS). Domestic, occupational, transportation and leisure physical activity were assessed in terms of metabolic equivalent (MET)-hours-per-week to account for both intensity and time spent. Sleep duration was categorized into three groups: ≤ 7 hours, 7-9 hours, and ≥ 9 hours. Insulin resistance was evaluated by the homeostasis model of assessment (HOMA) and defined as the highest quartile of HOMA.
  
  
  RESULTS
  Total physical activity was mainly composed of occupational activity (75.1%), followed orderly by domestic, transportation and leisure time activity in both men and women. Total physical activity level was strongly negatively associated with fasting insulin and HOMA (p < 0.001). Among four types of physical activity, occupational activity was significantly negatively associated with HOMA after full adjustment (p < 0.05). Transportation activity was also negatively associated with HOMA when adjusted for age and gender (p = 0.028). Moreover, the combination of low physical activity and short sleep duration was associated with the highest odds of insulin resistance (adjusted OR = 3.26, 95% CI: 1.57-6.78), compared to those with high physical activity and adequate sleep duration.
  
  
  CONCLUSIONS
  Physical activity, mainly occupational physical activity, was negatively associated with insulin resistance in non-diabetic Chinese population, independently of potential confounders. There was a synergic effect of low physical activity and short sleep duration on insulin resistance.
authors.affiliation: Department of Nutrition and Food Hygiene, Jiangsu Provincial Center for Disease Control and Prevention, Nanjing 210009, China. huizuo97@gmail.com
authors.forename: Hui
authors.initials: H
authors.lastname: Zuo
authors.forename: Zumin
authors.initials: Z
authors.lastname: Shi
authors.forename: Baojun
authors.initials: B
authors.lastname: Yuan
authors.forename: Yue
authors.initials: Y
authors.lastname: Dai
authors.forename: Gang
authors.initials: G
authors.lastname: Hu
authors.forename: Gaolin
authors.initials: G
authors.lastname: Wu
authors.forename: Akhtar
authors.initials: A
authors.lastname: Hussain
mesh_terms: D000203:Activities of Daily Living / Q000523:psychology*; D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002681:China; D005260:Female; D006306:Health Surveys; D006706:Homeostasis; D006801:Humans; D007333:Insulin Resistance; D008019:Life Style; D016015:Logistic Models; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D009043:Motor Activity / Q000502:physiology*; D012111:Residence Characteristics; D012890:Sleep / Q000502:physiology*; D012923:Social Class; D011795:Surveys and Questionnaires; D013997:Time Factors; D014937:Work / Q000502:physiology