title: Smoking habits and leukocyte telomere length dynamics among older adults: Results from the ESTHER cohort.
abstract: OBJECTIVE
  Leukocyte telomere length (LTL) shortens with age and short LTL has been associated with increased mortality and increased risk for some age-related outcomes. This study aims to analyse the associations of smoking habits with LTL and rate of LTL change per year in older adults.
  
  
  METHODS
  LTL was measured by quantitative PCR at baseline in 3600 older adults, who were enrolled in a population-based cohort study in Germany. For longitudinal analyses, measurements were repeated in blood samples obtained at 8-year follow-up from 1000 participants. Terminal Restriction Fragment analysis was additionally performed in a sub-sample to obtain absolute LTL in base pairs. Multivariate linear regression models were used to estimate associations of smoking habits with baseline LTL and changes in LTL over time.
  
  
  RESULTS
  LTL was inversely associated with age (r=-0.090, p<0.0001). Women had longer LTL than men (p<0.0001). Smoking was inversely associated with LTL. On average, current smokers had 73 base pairs (BP) shorter LTL compared to never smokers. Smoking intensity and pack-years of smoking were also inversely associated with LTL, and a positive association was observed with years since smoking cessation. Slower LTL attrition rates were observed in ever smokers over 8years of follow-up.
  
  
  CONCLUSIONS
  Our cross-sectional analysis supports suggestions that smoking might contribute to shortening of LTL but this relationship could not be shown longitudinally. The overall rather small effect sizes observed for smoking-related variables suggest that LTL reflects smoking-related health hazards only to a very limited extent.
authors.affiliation: Division of Clinical Epidemiology and Aging Research, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 581, 69120 Heidelberg, Germany; Network Aging Research (NAR), University of Heidelberg, Heidelberg, Germany.
authors.forename: Aysel
authors.initials: A
authors.lastname: Müezzinler
authors.affiliation: Division of Clinical Epidemiology and Aging Research, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 581, 69120 Heidelberg, Germany. Electronic address: u.mons@dkfz.de.
authors.forename: Ute
authors.initials: U
authors.lastname: Mons
authors.affiliation: Division of Clinical Epidemiology and Aging Research, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 581, 69120 Heidelberg, Germany; German Cancer Consortium (DKTK), Heidelberg, Germany.
authors.forename: Aida Karina
authors.initials: AK
authors.lastname: Dieffenbach
authors.affiliation: Division of Clinical Epidemiology and Aging Research, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 581, 69120 Heidelberg, Germany.
authors.forename: Katja
authors.initials: K
authors.lastname: Butterbach
authors.affiliation: Division of Clinical Epidemiology and Aging Research, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 581, 69120 Heidelberg, Germany.
authors.forename: Kai-Uwe
authors.initials: KU
authors.lastname: Saum
authors.affiliation: Genomics and Proteomics Core Facility, German Cancer Research Center, Im Neuenheimer Feld 580, 69120 Heidelberg, Germany.
authors.forename: Matthias
authors.initials: M
authors.lastname: Schick
authors.affiliation: Division of Genetics of Skin Carcinogenesis, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg, Germany.
authors.forename: Hermann
authors.initials: H
authors.lastname: Stammer
authors.affiliation: Division of Genetics of Skin Carcinogenesis, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg, Germany.
authors.forename: Petra
authors.initials: P
authors.lastname: Boukamp
authors.affiliation: Saarland Cancer Registry, Präsident-Baltz-Straße 5, 66119 Saarbrücken, Germany.
authors.forename: Bernd
authors.initials: B
authors.lastname: Holleczek
authors.affiliation: Saarland Cancer Registry, Präsident-Baltz-Straße 5, 66119 Saarbrücken, Germany.
authors.forename: Christa
authors.initials: C
authors.lastname: Stegmaier
authors.affiliation: Division of Clinical Epidemiology and Aging Research, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 581, 69120 Heidelberg, Germany.
authors.forename: Hermann
authors.initials: H
authors.lastname: Brenner
mesh_terms: D000368:Aged; D000375:Aging / Q000097:blood / Q000235:genetics*; D003430:Cross-Sectional Studies; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007962:Leukocytes / Q000648:ultrastructure*; D008297:Male; D008875:Middle Aged; D012907:Smoking / Q000097:blood / Q000235:genetics*; D016615:Telomere / Q000502:physiology; D059505:Telomere Homeostasis / Q000502:physiology*; D059506:Telomere Shortening / Q000502:physiology
keywords: Age; Ageing; Cigarette smoking; ESTHER; Smoking; Telomere length