title: Lifetime secondhand smoke exposure and childhood and adolescent asthma: findings from the PIAMA cohort.
abstract: Secondhand smoke (SHS) exposure is a modifiable risk factor associated with childhood asthma. Associations with adolescent asthma and the relevance of the timing and patterns of exposure are unclear. Knowledge of critical windows of exposure is important for targeted interventions.
  
  
  
  We used data until age 17 from 1454 children of the Dutch population-based PIAMA birth cohort. Residential SHS exposure was assessed through parental questionnaires completed at ages 3 months, 1-8 (yearly), 11, 14, and 17 years. Lifetime exposure was determined as; a) time window-specific exposure (prenatal, infancy, preschool, primary school, and secondary school); b) lifetime cumulative exposure; c) longitudinal exposure patterns using latent class growth modeling (LCGM). Generalized estimation equations and logistic regression were used to analyze associations between exposure and asthma at ages 4 to 17 years, adjusting for potential confounders.
  
  
  
  With all three methods, we consistently found no association between SHS exposure and asthma at ages 4 to 17 years e.g. adjusted overall odds ratio (95% confidence interval) 0.67 (0.41-1.12), 1.00 (0.66-1.51) and 0.67 (0.41-1.11) for prenatal maternal active smoking, infancy, and preschool school time window exposures, respectively.
  
  
  
  We assessed lifetime SHS exposure using different methods. Different timing and patterns of SHS exposure were not associated with an increased risk of asthma in childhood and adolescence in our study. More longitudinal studies could investigate effects of lifetime SHS exposure on asthma in adolescence and later life.
authors.affiliation: Institute for Risk Assessment Sciences (IRAS), Division of Environmental Epidemiology, Utrecht University, P.O. Box 80178, 3508 TD, Utrecht, The Netherlands. E.B.milanzi@uu.nl.
authors.forename: Edith B
authors.initials: EB
authors.lastname: Milanzi
authors.affiliation: Institute for Risk Assessment Sciences (IRAS), Division of Environmental Epidemiology, Utrecht University, P.O. Box 80178, 3508 TD, Utrecht, The Netherlands.|Julius Center for Health Sciences and Primary Care, University Medical Center Utrecht, Utrecht, The Netherlands.
authors.forename: Bert
authors.initials: B
authors.lastname: Brunekreef
authors.affiliation: Department of Pediatric Pulmonology and Pediatric Allergology, GRIAC Research Institute, University of Groningen, University Medical Center Groningen, Beatrix Children's Hospital, Groningen, The Netherlands.|Groningen Research Institute for Asthma and COPD (GRIAC), University of Groningen, University Medical Center Groningen, Groningen, The Netherlands.
authors.forename: Gerard H
authors.initials: GH
authors.lastname: Koppelman
authors.affiliation: Centre for Prevention and Health Services Research, National Institute for Public Health and the Environment (RIVM), Bilthoven, The Netherlands.
authors.forename: Alet H
authors.initials: AH
authors.lastname: Wijga
authors.affiliation: Julius Center for Health Sciences and Primary Care, University Medical Center Utrecht, Utrecht, The Netherlands.
authors.forename: Lenie
authors.initials: L
authors.lastname: van Rossem
authors.affiliation: Groningen Research Institute for Asthma and COPD (GRIAC), University of Groningen, University Medical Center Groningen, Groningen, The Netherlands.|Department of Epidemiology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands.
authors.forename: Judith M
authors.initials: JM
authors.lastname: Vonk
authors.affiliation: Julius Center for Health Sciences and Primary Care, University Medical Center Utrecht, Utrecht, The Netherlands.
authors.forename: Henriëtte A
authors.initials: HA
authors.lastname: Smit
authors.affiliation: Institute for Risk Assessment Sciences (IRAS), Division of Environmental Epidemiology, Utrecht University, P.O. Box 80178, 3508 TD, Utrecht, The Netherlands.
authors.forename: Ulrike
authors.initials: U
authors.lastname: Gehring
mesh_terms: D000293:Adolescent; D001249:Asthma / Q000453:epidemiology*; D002648:Child; D000067576:Child Health; D002675:Child, Preschool; D004781:Environmental Exposure; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D008431:Maternal-Fetal Exchange; D009426:Netherlands / Q000453:epidemiology; D016017:Odds Ratio; D011247:Pregnancy; D014028:Tobacco Smoke Pollution
chemical_list: D014028:Tobacco Smoke Pollution
keywords: Asthma; Environmental epidemiology; Longitudinal data; Secondhand smoke