title: Recent increases in efficiency in cigarette nicotine delivery: implications for tobacco control.
abstract: BACKGROUND
  Recent increases in nicotine yield of cigarettes sold in the United States have been attributed by tobacco manufacturers to natural variation in agricultural products. We tested this assertion using data reported by the manufacturers.
  
  
  METHODS
  Data were collected from the annual reports filed with the Massachusetts Department of Public Health by 4 major manufacturers of cigarettes from 1997 to 2012. Reportable measures included nicotine yield (mg/cig) in smoke generated by a smoking machine based on the Massachusetts smoking regimen and nicotine content in the unburned tobacco per cigarette (mg/cig). We used multilevel linear mixed-effect models to examine temporal trends in and predictors of these measures, overall and by brand style and by brand family.
  
  
  RESULTS
  While nicotine content remained relatively stable in the range of 12-14 mg/cig between 1998 and 2012, average nicotine yield increased significantly (p < .01) over time and ranged from the lowest level of 1.65 mg/cigarette in 1999 to the highest level of 1.89 mg/cigarette in 2011. Nicotine yield and yield-to-content ratio varied significantly among manufacturers and brand families. When controlling for market category and all available design features, the yield-to-content ratio of all manufacturers except Lorillard increased significantly over time.
  
  
  CONCLUSIONS
  The data provided by tobacco manufacturers suggest that the increasing trend in yield is not related to variations in nicotine content but to the yield-to-content ratio, which contradicts their assertions of agricultural variations. Nicotine yield and yield-to-content ratio are controllable features of cigarettes, and they should be monitored and regulated by government agencies.
authors.affiliation: Bureau of Community Health and Prevention, Massachusetts Department of Public Health, Boston, MA;
authors.forename: Thomas
authors.initials: T
authors.lastname: Land
authors.forename: Lois
authors.initials: L
authors.lastname: Keithly
authors.forename: Kevin
authors.initials: K
authors.lastname: Kane
authors.forename: Lili
authors.initials: L
authors.lastname: Chen
authors.forename: Mark
authors.initials: M
authors.lastname: Paskowsky
authors.forename: Doris
authors.initials: D
authors.lastname: Cullen
authors.forename: Rashelle B
authors.initials: RB
authors.lastname: Hayes
authors.forename: Wenjun
authors.initials: W
authors.lastname: Li
mesh_terms: D008404:Massachusetts; D009538:Nicotine / Q000032:analysis*; D012906:Smoke / Q000032:analysis*; D019460:Tobacco Industry; D062789:Tobacco Products / Q000032:analysis*
chemical_list: D012906:Smoke; D009538:Nicotine