title: Long-term smoking cessation and heart rate dynamics in an aging healthy cohort: Is it possible to fully recover?
abstract: OBJECTIVE
  To evaluate the long-term influence of smoking cessation on the regulation of the autonomic cardiovascular system in an aging general population, using the subpopulation of lifelong non-smokers as control group.
  
  
  METHODS
  We analyzed 1481 participants aged ≥50 years from the SAPALDIA cohort. In each participant, heart rate variability and heart rate dynamics were characterized by means of various quantitative analyzes of the inter-beat interval time series generated from 24-hour electrocardiogram recordings. Each parameter obtained was then used as the outcome variable in multivariable linear regression models in order to evaluate the association with smoking status and time elapsed since smoking cessation. The models were adjusted for known confounding factors and stratified by the time elapsed since smoking cessation.
  
  
  RESULTS
  Our findings indicate that smoking triggers adverse changes in the regulation of the cardiovascular system, even at low levels of exposure since current light smokers exhibited significant changes as compared to lifelong non-smokers. Moreover, there was evidence for a dose-response effect. Indeed, the changes observed in current heavy smokers were more marked as compared to current light smokers. Furthermore, full recovery was achieved in former smokers (i.e., normalization to the level of lifelong non-smokers). However, while light smokers fully recovered within the 15 first years of cessation, heavy former smokers might need up to 15-25 years to fully recover.
  
  
  CONCLUSIONS
  This study supports the substantial benefits of smoking cessation, but also warns of important long-term alterations caused by heavy smoking.
authors.affiliation: University of Basel, University Children's Hospital (UKBB), Basel, Switzerland; Swiss Tropical and Public Health Institute, Basel, Switzerland. Electronic address: delphine.gd@gmail.com.
authors.forename: Delphine
authors.initials: D
authors.lastname: Girard
authors.affiliation: University of Basel, University Children's Hospital (UKBB), Basel, Switzerland.
authors.forename: Edgar
authors.initials: E
authors.lastname: Delgado-Eckert
authors.affiliation: Swiss Tropical and Public Health Institute, Basel, Switzerland; University of Basel, Basel, Switzerland.
authors.forename: Emmanuel
authors.initials: E
authors.lastname: Schaffner
authors.affiliation: University of Basel, University Children's Hospital (UKBB), Basel, Switzerland.
authors.forename: Christoph
authors.initials: C
authors.lastname: Häcki
authors.affiliation: Swiss Tropical and Public Health Institute, Basel, Switzerland; University of Basel, Basel, Switzerland.
authors.forename: Martin
authors.initials: M
authors.lastname: Adam
authors.affiliation: University of Basel, University Children's Hospital (UKBB), Basel, Switzerland.
authors.forename: Georgette L
authors.initials: GL
authors.lastname: Stern
authors.affiliation: University of Basel, University Children's Hospital (UKBB), Basel, Switzerland.
authors.forename: Nitin
authors.initials: N
authors.lastname: Kumar
authors.affiliation: Federal Office for the Environment FOEN, Air Quality Management Section, Bern, Switzerland.
authors.forename: Denise
authors.initials: D
authors.lastname: Felber Dietrich
authors.affiliation: Zürcher Höhenklinik Wald, Faltigberg-Wald, Switzerland.
authors.forename: Alexander
authors.initials: A
authors.lastname: Turk
authors.affiliation: Regional Hospital of Lugano, Division of Pulmonary Medicine, Lugano, Switzerland.
authors.forename: Marco
authors.initials: M
authors.lastname: Pons
authors.affiliation: Swiss Tropical and Public Health Institute, Basel, Switzerland; University of Basel, Basel, Switzerland.
authors.forename: Nino
authors.initials: N
authors.lastname: Künzli
authors.affiliation: University Hospital of Geneve, Health and Community Medicine, Geneve, Switzerland.
authors.forename: Jean-Michel
authors.initials: JM
authors.lastname: Gaspoz
authors.affiliation: University Hospital of Geneve, Pneumology, Geneve, Switzerland.
authors.forename: Thierry
authors.initials: T
authors.lastname: Rochat
authors.affiliation: Swiss Tropical and Public Health Institute, Basel, Switzerland; University of Basel, Basel, Switzerland.
authors.forename: Christian
authors.initials: C
authors.lastname: Schindler
authors.affiliation: Swiss Tropical and Public Health Institute, Basel, Switzerland; University of Basel, Basel, Switzerland.
authors.forename: Nicole
authors.initials: N
authors.lastname: Probst-Hensch
authors.affiliation: University of Basel, University Children's Hospital (UKBB), Basel, Switzerland.
authors.forename: Urs
authors.initials: U
authors.lastname: Frey
mesh_terms: D000375:Aging / Q000502:physiology*; D015331:Cohort Studies; D015716:Electrocardiography, Ambulatory; D005260:Female; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D008019:Life Style; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D020127:Recovery of Function; D012907:Smoking / Q000009:adverse effects / Q000453:epidemiology; D016540:Smoking Cessation / Q000706:statistics & numerical data; D000074606:Smoking Prevention; D013557:Switzerland; D013997:Time Factors
keywords: Heart rate variability; Nonlinear dynamics; Recovery of function; Smoking cessation