title: Familial risk moderates the association between sleep and zBMI in children.
abstract: OBJECTIVE
  A cumulative risk approach was used to examine the moderating effect of familial risk factors on relations between actigraphy-based sleep quantity (minutes) and quality (efficiency) and sex- and age-standardized body mass index (zBMI).
  
  
  METHODS
  The sample included 124 boys and 104 girls with a mean age of 10.41 years (SD = 0.67). Children wore actigraphs for 1 week, and their height and weight were assessed in the lab.
  
  
  RESULTS
  After controlling for potential confounds, multiple regression analyses indicated that sleep minutes predicted children's zBMI and that both sleep minutes and efficiency interacted with family risk in the prediction of zBMI. The association between poor sleep and zBMI was especially evident for children exposed to higher levels of family risk.
  
  
  CONCLUSIONS
  Findings suggest that not all children who exhibit poor sleep are at equal risk for higher zBMI and that familial and contextual conditions need to be considered in this link.
authors.affiliation: Department of Human Development and Family Studies, Auburn University, Auburn, AL 36849-5214, USA. ejb0009@auburn.edu
authors.forename: Erika J
authors.initials: EJ
authors.lastname: Bagley
authors.forename: Mona
authors.initials: M
authors.lastname: El-Sheikh
mesh_terms: D056044:Actigraphy / Q000379:methods; D015992:Body Mass Index; D002648:Child; D015897:Comorbidity; D005260:Female; D020022:Genetic Predisposition to Disease; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D009765:Obesity / Q000453:epidemiology / Q000235:genetics / Q000503:physiopathology*; D011237:Predictive Value of Tests; D012307:Risk Factors; D012890:Sleep / Q000235:genetics / Q000502:physiology*; D012893:Sleep Wake Disorders / Q000453:epidemiology / Q000235:genetics / Q000503:physiopathology*
keywords: children; obesity; risk; sleep