title: Gene-environment contributions to energy and macronutrient intakes in 9-year-old children: results from the Quebec Newborn Twin Study.
abstract: BACKGROUND
  Few twin studies have examined nutrition-related phenotypes among children, and none has investigated energy and macronutrient intakes.
  
  
  OBJECTIVE
  The objective was to quantify genetic and environmental influences on variations in energy and macronutrient intakes among children aged 9 years.
  
  
  METHODS
  We conducted a nutrition study among children participating in the Quebec Newborn Twin Study, a population-based birth cohort of twins. We derived dietary data from two multiple-pass 24-hour dietary recalls with a parent and his or her child. The analysis employed a classic twin study design and used data from 379 twin pairs.
  
  
  RESULTS
  Univariate analyses indicate that heritability for mean daily energy (kcal) and macronutrient (g) intakes was moderate, ranging from 0.34 (95% CI: 0.22, 0.46) to 0.42 (0.31, 0.53). Genetic effects also accounted for 0.28 (0.16, 0.40) of the variance in percent of energy from lipids, while only environmental (shared and unique) effects accounted for the variance in percent of energy from proteins and carbohydrates. The shared environment did not contribute to variations in daily intakes for most of the nutritional variables under study. Multivariate analyses suggest the presence of macronutrient-specific genetic influences for lipids and carbohydrates, estimated at 0.12 (0.04, 0.19) and 0.20 (0.11, 0.29) respectively.
  
  
  CONCLUSIONS
  The unique environment (i.e., not shared by family members) has the largest influence on variances in daily energy and macronutrient intakes in 9-year-old children. This finding underscores the need to take obesogenic environments into account when planning dietary interventions for younger populations.
authors.affiliation: Institute of Population Health, University of Ottawa, 1 Stewart St., Ottawa, ON K1N 6N5, Canada. lise.dubois@uottawa.ca
authors.forename: Lise
authors.initials: L
authors.lastname: Dubois
authors.forename: Maikol
authors.initials: M
authors.lastname: Diasparra
authors.forename: Brigitte
authors.initials: B
authors.lastname: Bédard
authors.forename: Jaakko
authors.initials: J
authors.lastname: Kaprio
authors.forename: Bénédicte
authors.initials: B
authors.lastname: Fontaine-Bisson
authors.forename: Daniel
authors.initials: D
authors.lastname: Pérusse
authors.forename: Richard
authors.initials: R
authors.lastname: Tremblay
authors.forename: Michel
authors.initials: M
authors.lastname: Boivin
mesh_terms: D002648:Child; D004435:Eating / Q000235:genetics*; D002149:Energy Intake / Q000235:genetics*; D005247:Feeding Behavior; D005260:Female; D059647:Gene-Environment Interaction; D006801:Humans; D008297:Male; D011792:Quebec; D014429:Twins, Dizygotic / Q000235:genetics*; D014430:Twins, Monozygotic / Q000235:genetics*
keywords: Children; Energy intake; Environment; Heritability; Macronutrients; Twins