title: Physical Activity Domains/Recommendations and Leukocyte Telomere Length in U.S. Adults.
abstract: The purpose of this study was to examine the associations between different physical activity (PA) domains, PA recommendations, and leukocyte telomere length (LTL) using data from a nationally representative sample of U.S. adults in the National Health and Nutrition Examination Survey, 1999-2002.
  
  
  
  A total of 6933 U.S. adults (3402 men, 3531 women; age range: 20-84 yr) who completed demographic, general health and PA questionnaires and provided a blood sample were included in the analyses. Multivariable-adjusted linear regression models were used to determine associations between PA (domain-specific PA [household/yard work PA, transportation PA, moderate leisure time PA (LTPA), and vigorous LTPA], total moderate PA and PA recommendation groups), and log-transformed LTL adjusting for age, gender, education, cigarette smoking, alcohol consumption, and body mass index.
  
  
  
  On average, an increase of 1 h·wk of vigorous LTPA was associated with a 0.31% (P < 0.001) longer LTL, and an increase of 1 h·wk of household/yard work PA was associated with a 0.21% (P = 0.03) shorter LTL while adjusted for sociodemographic and health behavior covariates. Neither transportation PA nor moderate LTPA was significantly associated with LTL. In addition, compared with not meeting the PA recommendation (<150 min·wk), exceeding the recommended PA levels (≥300 min·wk) was positively associated with longer LTL (P = 0.04), whereas there was no difference in telomere length between those not meeting versus those meeting the PA recommendation (150-299 min·wk).
  
  
  
  Greater engagement in vigorous LTPA and exceeding the PA recommendation may have a protective effect against telomere shortening. Future studies should examine the association between PA and LTL by exploring potential mediators such as sedentary behavior, genetics, nutrition, and chronic diseases.
authors.affiliation: 1Department of Exercise and Health Sciences, University of Massachusetts Boston, Boston, MA; 2Department of Nursing, College of Nursing and Health Sciences, University of Massachusetts Boston, Boston, MA; 3Division of General Medicine and Primary Care, Beth Israel Deaconess Medical Center, Boston, MA; and 4Department of Medicine, Harvard Medical School, Boston, MA.
authors.forename: Elisa F
authors.initials: EF
authors.lastname: Ogawa
authors.forename: Suzanne G
authors.initials: SG
authors.lastname: Leveille
authors.forename: Julie A
authors.initials: JA
authors.lastname: Wright
authors.forename: Ling
authors.initials: L
authors.lastname: Shi
authors.forename: Sarah M
authors.initials: SM
authors.lastname: Camhi
authors.forename: Tongjian
authors.initials: T
authors.lastname: You
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000502:physiology; D015444:Exercise / Q000502:physiology*; D005260:Female; D006801:Humans; D007962:Leukocytes / Q000502:physiology*; D008297:Male; D008875:Middle Aged; D012959:Socioeconomic Factors; D016615:Telomere / Q000502:physiology*; D059506:Telomere Shortening; D055815:Young Adult