title: Time to first cigarette and lung cancer risk in Japan.
abstract: BACKGROUND
  Cigarette smoking is the major cause of lung cancer (LC). Although the time to first cigarette (TTFC) of the day is a distinct indicator of nicotine dependence, little information is available on its possible relation to LC.
  
  
  METHODS
  This case-control study includes a total of 1572 incident LC cases and 1572 non-cancer controls visiting for the first time the Aichi Cancer Center Hospital between 2001 and 2005. We estimated the odds ratio (OR) and 95% confidence interval (CI) for TTFC using a logistic regression model after adjustment for several potential confounders.
  
  
  RESULTS
  TTFC was inversely associated with the risk of LC. This association was consistent across histological subtypes of LC. For all LCs considered among ever smokers and after accurate allowance for smoking quantity and duration, besides other relevant covariates, compared with TTFC >60 min, the adjusted ORs were 1.08 (95% CI, 0.73-1.61) for TTFC of 31-60 min, 1.40 (0.98-2.01) for 6-30 min and 1.86 (1.28-2.71) for within 5 min (Ptrend, < 0.001). Statistically marginally significant heterogeneity by histological subtype was observed (Pheterogeneity, 0.002).
  
  
  CONCLUSIONS
  Nicotine dependence, as indicated by the TTFC, is associated with increased risk of LC and is therefore an independent marker of exposure to tobacco smoking.
authors.affiliation: Division of Epidemiology and Prevention, Aichi Cancer Center Research Institute, Nagoya, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Ito
authors.forename: S
authors.initials: S
authors.lastname: Gallus
authors.forename: S
authors.initials: S
authors.lastname: Hosono
authors.forename: I
authors.initials: I
authors.lastname: Oze
authors.forename: K
authors.initials: K
authors.lastname: Fukumoto
authors.forename: Y
authors.initials: Y
authors.lastname: Yatabe
authors.forename: T
authors.initials: T
authors.lastname: Hida
authors.forename: T
authors.initials: T
authors.lastname: Mitsudomi
authors.forename: E
authors.initials: E
authors.lastname: Negri
authors.forename: K
authors.initials: K
authors.lastname: Yokoi
authors.forename: K
authors.initials: K
authors.lastname: Tajima
authors.forename: C
authors.initials: C
authors.lastname: La Vecchia
authors.forename: H
authors.initials: H
authors.lastname: Tanaka
authors.forename: K
authors.initials: K
authors.lastname: Matsuo
mesh_terms: D000328:Adult; D000368:Aged; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D007564:Japan / Q000453:epidemiology; D008175:Lung Neoplasms / Q000150:complications / Q000453:epidemiology* / Q000473:pathology; D008297:Male; D008875:Middle Aged; D012307:Risk Factors; D012907:Smoking; D013997:Time Factors; D014029:Tobacco Use Disorder / Q000150:complications / Q000473:pathology*
keywords: addiction; lung cancer; nicotine dependence; smoking