title: Associations ofLEP,CRH,ICAM-1, and LINE-1 methylation, measured in saliva, with waist circumference, body mass index, and percent body fat in mid-childhood.
abstract: Genetics explains a small proportion of variance in body mass index at the population level. Epigenetics, commonly measured by gene methylation, holds promise for understanding obesity risk factors and mechanisms.
  
  
  
  Participants were 431 adolescents aged 10-15 years. BMI z-score, waist circumference z-score, and percent body fat were measured. Saliva samples were collected and methylation of promoter regions of four candidate genes or sequences (LEP,ICAM-1,CRH, and LINE-1) were measured in 3-4 CpG sites each. Linear regression was used to identify associations of methylation with obesity-related outcomes.
  
  
  
  After adjusting for age, in sex-stratified analysis, the three obesity-related outcomes were negatively associated withLEPmethylation in obese boys only. There were no associations of methylation of the other genes or sequences and the obesity-related outcomes.
  
  
  
  Our results are consistent with prior studies that reported sex differences in associations of obesity-related outcomes withLEPmethylation, and also as would be expected in adipose tissue, the source of circulating leptin. The findings suggest that saliva might be an acceptable tissue for epigenetics studies in adolescents.
authors.affiliation: Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD USA.
authors.forename: Jocelyn
authors.initials: J
authors.lastname: Dunstan
authors.affiliation: Department of Environmental Health and Engineering, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD USA.
authors.forename: Joseph P
authors.initials: JP
authors.lastname: Bressler
authors.affiliation: Department of Psychiatry and Behavioral Sciences, Johns Hopkins School of Medicine, Baltimore, MD USA.
authors.forename: Timothy H
authors.initials: TH
authors.lastname: Moran
authors.affiliation: Department of Environmental Health and Engineering, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD USA.
authors.forename: Jonathan S
authors.initials: JS
authors.lastname: Pollak
authors.affiliation: Department of Epidemiology and Health Services Research, Geisinger Health System, Danville, PA USA.
authors.forename: Annemarie G
authors.initials: AG
authors.lastname: Hirsch
authors.affiliation: Department of Epidemiology and Health Services Research, Geisinger Health System, Danville, PA USA.
authors.forename: Lisa
authors.initials: L
authors.lastname: Bailey-Davis
authors.affiliation: Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD USA.
authors.forename: Thomas A
authors.initials: TA
authors.lastname: Glass
authors.affiliation: Department of Environmental Health and Engineering, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD USA.|Department of Epidemiology and Health Services Research, Geisinger Health System, Danville, PA USA.
authors.forename: Brian S
authors.initials: BS
authors.lastname: Schwartz
mesh_terms: D000293:Adolescent; D015992:Body Mass Index; D002648:Child; D003346:Corticotropin-Releasing Hormone / Q000235:genetics*; D019175:DNA Methylation; D044127:Epigenesis, Genetic; D005260:Female; D006801:Humans; D018799:Intercellular Adhesion Molecule-1 / Q000235:genetics*; D020738:Leptin / Q000235:genetics*; D020084:Long Interspersed Nucleotide Elements; D008297:Male; D009765:Obesity / Q000235:genetics*; D012727:Sex Characteristics; D055105:Waist Circumference
chemical_list: D020738:Leptin; D018799:Intercellular Adhesion Molecule-1; D003346:Corticotropin-Releasing Hormone
keywords: CRH; DNA methylation; Epigenetics; ICAM-1; LEP; LINE-1; Obesity; Sex differences