title: Leukocyte telomere length in healthy Caucasian and African-American adolescents: relationships with race, sex, adiposity, adipokines, and physical activity.
abstract: OBJECTIVE
  To examine the relationships of race, sex, adiposity, adipokines, and physical activity to telomere length in adolescents.
  
  
  METHODS
  Leukocyte telomere length (T/S ratio) was assessed cross-sectionally in 667 adolescents (aged 14-18 years; 48% African-Americans; 51% girls) using a quantitative polymerase chain reaction method. Generalized estimating equations analyses were performed.
  
  
  RESULTS
  Telomere length was greater in the African-American adolescents than in the Caucasian adolescents (age- and sex-adjusted T/S ratio ± SE, 1.32 ± 0.01 vs 1.27 ± 0.01: P = .014) and greater in girls than in boys (age- and race-adjusted T/S ratio ± SE, 1.31 ± 0.01 vs 1.27 ± 0.01; P = .007). None of the adiposity or adipokine measures explained a significant proportion of the variance in telomere length. Vigorous physical activity was positively associated with telomere length (adjusted R(2) = 0.019; P = .009) and accounted for 1.9% of the total variance only in girls.
  
  
  CONCLUSIONS
  This study, conducted in a biracial adolescent cohort, demonstrated that (1) race and sex differences in telomere length have already emerged during adolescence; (2) adiposity and adipokines are not associated with telomere length at this age; and (3) the antiaging effect of vigorous physical activity may begin in youth, especially in girls.
authors.affiliation: Department of Pediatrics, Georgia Prevention Institute, Medical College of Georgia, Augusta, GA 30912-3715, USA. hzhu@mail.mcg.edu
authors.forename: Haidong
authors.initials: H
authors.lastname: Zhu
authors.forename: Xiaoling
authors.initials: X
authors.lastname: Wang
authors.forename: Bernard
authors.initials: B
authors.lastname: Gutin
authors.forename: Catherine L
authors.initials: CL
authors.lastname: Davis
authors.forename: Daniel
authors.initials: D
authors.lastname: Keeton
authors.forename: Jeffrey
authors.initials: J
authors.lastname: Thomas
authors.forename: Inger
authors.initials: I
authors.lastname: Stallmann-Jorgensen
authors.forename: Grace
authors.initials: G
authors.lastname: Mooken
authors.forename: Vanessa
authors.initials: V
authors.lastname: Bundy
authors.forename: Harold
authors.initials: H
authors.lastname: Snieder
authors.forename: Pim
authors.initials: P
authors.lastname: van der Harst
authors.forename: Yanbin
authors.initials: Y
authors.lastname: Dong
mesh_terms: D054392:Adipokines / Q000097:blood*; D050154:Adiposity / Q000208:ethnology* / Q000235:genetics*; D000293:Adolescent; D001741:Black or African American / Q000235:genetics; D000886:Anthropometry; D015992:Body Mass Index; D003430:Cross-Sectional Studies; D005260:Female; D020022:Genetic Predisposition to Disease / Q000453:epidemiology; D006304:Health Status; D006801:Humans; D007962:Leukocytes; D009043:Motor Activity / Q000502:physiology*; D009765:Obesity / Q000208:ethnology / Q000235:genetics; D016133:Polymerase Chain Reaction / Q000379:methods; D018570:Risk Assessment; D012680:Sensitivity and Specificity; D012737:Sex Factors; D016615:Telomere / Q000235:genetics*; D044465:White People / Q000235:genetics
chemical_list: D054392:Adipokines