title: Cigarette smoking and periodontal disease among 32-year-olds: a prospective study of a representative birth cohort.
abstract: BACKGROUND
  Smoking is recognized as the primary behavioural risk factor for periodontal attachment loss (AL), but confirmatory data from prospective cohort studies are scarce.
  
  
  OBJECTIVE
  To quantify the association between cigarette smoking patterns and AL by age 32.
  
  
  METHODS
  Periodontal examinations were conducted at ages 26 and 32 in a longstanding prospective study of a birth cohort born in Dunedin (New Zealand) in 1972/1973. Longitudinal categorization of smoking exposure was undertaken using data collected at ages 15, 18, 21, 26 and 32.
  
  
  RESULTS
  Complete data were available for 810 individuals of whom 48.9% had ever smoked (31.5% were current smokers). Compared with never-smokers, long-term smokers (and other age-32 smokers) had very high odds ratios (ORs of 7.1 and 5.7, respectively) for having 1 +sites with 5 +mm AL, and were more likely to be incident cases after age 26 (ORs of 5.2 and 3.2, respectively). Two-thirds of new cases after age 26 were attributable to smoking. There were no significant differences in periodontal health between never-smokers and those who had quit smoking after age 26.
  
  
  CONCLUSIONS
  Current and long-term smoking in young adults is detrimental to periodontal health, but smoking cessation may be associated with a relatively rapid improvement in the periodontium.
authors.affiliation: Department of Oral Sciences, School of Dentistry, The University of Otago, Otago, New Zealand. murray.thomson@stonebow.otago.ac.nz
authors.forename: W Murray
authors.initials: WM
authors.lastname: Thomson
authors.forename: Jonathan M
authors.initials: JM
authors.lastname: Broadbent
authors.forename: David
authors.initials: D
authors.lastname: Welch
authors.forename: James D
authors.initials: JD
authors.lastname: Beck
authors.forename: Richie
authors.initials: R
authors.lastname: Poulton
mesh_terms: D000293:Adolescent; D000328:Adult; D003753:Dental Health Surveys; D004812:Epidemiologic Methods; D005260:Female; D006801:Humans; D008297:Male; D017622:Periodontal Attachment Loss / Q000453:epidemiology / Q000209:etiology*; D010510:Periodontal Diseases / Q000453:epidemiology / Q000209:etiology; D012907:Smoking / Q000009:adverse effects* / Q000453:epidemiology; D016540:Smoking Cessation / Q000706:statistics & numerical data*; D013997:Time Factors