title: Associations between BMI and the FTO gene are age dependent: results from the GINI and LISA birth cohort studies up to age 6 years.
abstract: OBJECTIVE
  The association between polymorphisms in intron 1 of the fat mass and obesity associated gene (FTO) and obesity-related traits is one of the most robust associations reported for complex traits and is established both in adults and children. However, little is known about the longitudinal dynamics of these polymorphisms on body mass index (BMI), overweight, and obesity.
  
  
  METHODS
  This study is based on the 2,732 full-term neonates of the German GINI-plus and LISA-plus birth cohorts, for whom genotyping data on the FTO variants rs1558902 (T>A) or rs9935401 (G>A) were available. Children were followed from birth up to age 6 years. Up to 9 anthropometric measurements of BMI were obtained. Fractional-Polynomial-Generalized-Estimation-Equation modeling was used to assess developmental trends and their potential dependence on genotype status.
  
  
  RESULTS
  We observed no evidence for BMI differences between genotypes of both variants for the first 3 years of life. However, from age 3 years onwards, we noted a higher BMI for the homozygous minor alleles carriers in comparison to the other two genotype groups. However, evidence for statistical significance was reached from the age of 4 years onwards.
  
  
  CONCLUSIONS
  This is one of the first studies investigating in detail the development of BMI depending on FTO genotype between birth and the age of 6 years in a birth cohort not selected for the phenotype studied. We observed that the association between BMI and FTO genotype evolves gradually and becomes descriptively detectable from the age of 3 years onwards.
authors.affiliation: Institute of Epidemiology, German Research Center for Environmental Health, Helmholtz Zentrum München, Neuherberg, Germany. peter.rzehak@helmholtz-muenchen.de
authors.forename: Peter
authors.initials: P
authors.lastname: Rzehak
authors.forename: André
authors.initials: A
authors.lastname: Scherag
authors.forename: Harald
authors.initials: H
authors.lastname: Grallert
authors.forename: Stefanie
authors.initials: S
authors.lastname: Sausenthaler
authors.forename: Sibylle
authors.initials: S
authors.lastname: Koletzko
authors.forename: Carl Peter
authors.initials: CP
authors.lastname: Bauer
authors.forename: Beate
authors.initials: B
authors.lastname: Schaaf
authors.forename: Andrea
authors.initials: A
authors.lastname: von Berg
authors.forename: Dietrich
authors.initials: D
authors.lastname: Berdel
authors.forename: Michael
authors.initials: M
authors.lastname: Borte
authors.forename: Olf
authors.initials: O
authors.lastname: Herbarth
authors.forename: Ursula
authors.initials: U
authors.lastname: Krämer
authors.forename: Thomas
authors.initials: T
authors.lastname: Illig
authors.forename: H-Erich
authors.initials: HE
authors.lastname: Wichmann
authors.forename: Johannes
authors.initials: J
authors.lastname: Hebebrand
authors.forename: Joachim
authors.initials: J
authors.lastname: Heinrich
mesh_terms: D017677:Age Distribution; D000071516:Alpha-Ketoglutarate-Dependent Dioxygenase FTO; D015992:Body Mass Index; D002648:Child; D002675:Child, Preschool; D020022:Genetic Predisposition to Disease / Q000453:epidemiology; D005838:Genotype; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008137:Longitudinal Studies; D009765:Obesity / Q000453:epidemiology* / Q000235:genetics*; D011506:Proteins / Q000235:genetics*; D012044:Regression Analysis
chemical_list: D011506:Proteins; D000071516:Alpha-Ketoglutarate-Dependent Dioxygenase FTO; C526492:FTO protein, human