title: Joint Effect of Cigarette Smoking and Body Mass Index on White Blood Cell Count in Korean Adults.
abstract: BACKGROUND
  White blood cell count is an independent risk factor for cardiovascular disease. Several lifestyle and metabolic factors such as cigarette smoking and obesity are known to be associated with an elevated white blood cell count. However, the joint effect of cigarette smoking and obesity on white blood cell count has not yet been fully described.
  
  
  METHODS
  We explored the joint effect of cigarette smoking and obesity on white blood cell count using multiple logistic regression analyses after adjusting for confounding variables in a population-based, cross-sectional study of 416,065 Korean adults.
  
  
  RESULTS
  Cigarette smoking and body mass index have a dose-response relationship with a higher white blood cell count, but no synergistic interaction is observed between them (men, P for interaction=0.797; women, P for interaction=0.311). Cigarette smoking and body mass index might have an additive combination effect on high white blood cell count. Obese male smokers were 2.36 times more likely and obese female smokers 2.35 times more likely to have a high white blood cell count when compared with normal body mass index non-smokers.
  
  
  CONCLUSIONS
  Cigarette smoking and body mass index are independently associated with an elevated white blood cell count in both men and women.
authors.affiliation: Department of Family Medicine, Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: A-Ra
authors.initials: AR
authors.lastname: Cho
authors.affiliation: Department of Family Medicine, Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Won-Jun
authors.initials: WJ
authors.lastname: Choi
authors.affiliation: Department of Family Medicine, Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Shin-Hye
authors.initials: SH
authors.lastname: Kim
authors.affiliation: Department of Family Medicine, Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Jae-Yong
authors.initials: JY
authors.lastname: Shim
authors.affiliation: Department of Family Medicine, Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Yong-Jae
authors.initials: YJ
authors.lastname: Lee
keywords: Leukocyte Count; Obesity; Smoking