title: Movement-Based Behaviors and Leukocyte Telomere Length among US Adults.
abstract: BACKGROUND
  Short leukocyte telomere length (LTL) has become a hallmark characteristic of aging. Some, but not all, evidence suggests that physical activity (PA) may play an important role in attenuating age-related diseases and may provide a protective effect for telomeres. The purpose of this study was to examine the association between PA and LTL in a national sample of US adults from the National Health and Nutrition Examination Survey.
  
  
  METHODS
  National Health and Nutrition Examination Survey data from 1999 to 2002 (n = 6503; 20-84 yr) were used. Four self-report questions related to movement-based behaviors (MBB) were assessed. The four MBB included whether individuals participated in moderate-intensity PA, vigorous-intensity PA, walking/cycling for transportation, and muscle-strengthening activities. An MBB index variable was created by summing the number of MBB an individual engaged in (range, 0-4).
  
  
  RESULTS
  A clear dose-response relation was observed between MBB and LTL; across the LTL tertiles, respectively, the mean numbers of MBB were 1.18, 1.44, and 1.54 (Ptrend < 0.001). After adjustments (including age) and compared with those engaging in 0 MBB, those engaging in 1, 2, 3, and 4 MBB, respectively, had a 3% (P = 0.84), 24% (P = 0.02), 29% (P = 0.04), and 52% (P = 0.004) reduced odds of being in the lowest (vs highest) tertile of LTL; MBB was not associated with being in the middle (vs highest) tertile of LTL.
  
  
  CONCLUSIONS
  Greater engagement in MBB was associated with reduced odds of being in the lowest LTL tertile.
authors.affiliation: 1Center for Health Behavior Research, Department of Health, Exercise Science, and Recreation Management, University of Mississippi, University, MS; 2Kevser Ermin Applied Physiology Laboratory, Department of Health, Exercise Science, and Recreation Management, University of Mississippi, University, MS; and 3Blackburn Laboratory, Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA.
authors.forename: Paul D
authors.initials: PD
authors.lastname: Loprinzi
authors.forename: Jeremy P
authors.initials: JP
authors.lastname: Loenneke
authors.forename: Elizabeth H
authors.initials: EH
authors.lastname: Blackburn
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000502:physiology*; D006801:Humans; D007962:Leukocytes / Q000502:physiology*; D008875:Middle Aged; D009043:Motor Activity / Q000502:physiology*; D009749:Nutrition Surveys; D059506:Telomere Shortening; D055815:Young Adult