title: Sleep, but not other daily routines, mediates the association between maternal employment and BMI for preschool children.
abstract: BACKGROUND
  It has been established that the more time mothers spend working outside of the home, the more likely their preschool-aged children are to be overweight. However, the mechanisms explaining this relationship are not well understood. Our objective was to explore child sleep, dietary habits, TV time, and family mealtime routines as mediators of the relationship between maternal employment status (full-time, part-time, and no or minimal employment) and child body mass index (BMI) percentile.
  
  
  METHODS
  Data were drawn from waves 1 and 2 of STRONG Kids, a prospective panel study examining childhood obesity among parent-preschooler dyads (n = 247). Mothers reported their own work hours, their child's hours of nighttime sleep, dietary habits, TV time, and mealtime routines. Trained staff measured child height and weight.
  
  
  RESULTS
  Compared to working 0-19 h/week, both full-time (>35 h/week) and part-time (20-34 h/week) employment predicted higher child BMI percentile 1 year later. Hours of child nighttime sleep partially mediated the association between maternal full-time employment and child BMI percentile. Adjusting for individual and family characteristics, children whose mothers were employed full time were less likely to sleep longer hours than children whose mothers were employed 0-19 h/week (b = -0.49, p < 0.04). Shorter child nighttime sleep was associated with higher BMI percentile (b = -7.31, p < 0.001). None of the other mediation pathways tested were significant.
  
  
  CONCLUSIONS
  These findings add to the growing literature on the importance of adequate sleep for young children's health.
authors.affiliation: Human and Community Development, University of Illinois at Urbana-Champaign, 904 West Nevada Street, MC-081, Urbana, IL 61801, USA. Electronic address: kspeirs@illinois.edu.
authors.forename: Katherine E
authors.initials: KE
authors.lastname: Speirs
authors.affiliation: School of Social Work and College of Medicine, University of Illinois at Urbana-Champaign, 1010 West Nevada Street, Urbana, IL 61801, USA.
authors.forename: Janet M
authors.initials: JM
authors.lastname: Liechty
authors.affiliation: School of Social Work, University of Illinois at Urbana-Champaign, 1010 West Nevada Street, Urbana, IL 61801, USA.
authors.forename: Chi-Fang
authors.initials: CF
authors.lastname: Wu
mesh_terms: D000328:Adult; D015992:Body Mass Index; D002675:Child, Preschool; D004651:Employment / Q000706:statistics & numerical data; D005260:Female; D006801:Humans; D008297:Male; D009035:Mothers / Q000706:statistics & numerical data*; D063766:Pediatric Obesity / Q000209:etiology*; D011446:Prospective Studies; D012890:Sleep / Q000502:physiology*; D012892:Sleep Deprivation / Q000150:complications
keywords: BMI; Daily routines; Dietary quality; Maternal employment; Obesity; Preschool children; Sleep; Television viewing