title: Combined effects of smoking and systolic blood pressure on risk of coronary heart disease: a cohort study in Chinese women.
abstract: OBJECTIVE
  To quantify the combined effects of systolic blood pressure (SBP) and cigarette smoking on incident coronary heart disease (CHD) in women.
  
  
  METHODS
  Overall, 86,338 women aged >or=40 years were enrolled in 1991. The follow-up evaluation was conducted in 1999-2000, with a response rate of 92.9%.
  
  
  RESULTS
  A total of 829 CHD events (fatal and nonfatal) were observed among the participants who were free of cardiovascular diseases (CVD) at baseline. Higher SBP was significantly associated with more risk of CHD in both nonsmokers and current smokers (all p < 0.0001 for linear trends). Comparing with never smoking, both low and high levels of cigarettes smoked per day (1-7, and >or=8 cigarettes per day) and pack-years (<10, and >or=10 pack-years) were associated with increased risk of CHD in those with normal and high SBP. The multivariate adjusted relative risks (RRs) of CHD were 2.54 (95% confidence interval [CI] 2.00-3.23), 1.28 (1.01-1.63), and 1.57 (1.33-1.86) for current smokers with high SBP, current smokers with normal SBP, and nonsmokers with high SBP, respectively, compared with nonsmokers with normal SBP. The present study identified a statistically significant additive interaction between these two factors on CHD.
  
  
  CONCLUSIONS
  Our study indicated that the combined effects of cigarette smoking and high SBP could be expected to have extra adverse effects on CHD in women, which highlights the importance of multifactorial interventions to decrease the risk of CHD, for example, quitting smoking and treatment of high blood pressure in Chinese women.
authors.affiliation: Department of Evidence Based Medicine, Cardiovascular Institute & FuWai Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China.
authors.forename: Dongling
authors.initials: D
authors.lastname: Sun
authors.forename: Jie
authors.initials: J
authors.lastname: Cao
authors.forename: Xiaoqing
authors.initials: X
authors.lastname: Liu
authors.forename: Ling
authors.initials: L
authors.lastname: Yu
authors.forename: Chonghua
authors.initials: C
authors.lastname: Yao
authors.forename: Jianxin
authors.initials: J
authors.lastname: Li
authors.forename: Dahai
authors.initials: D
authors.lastname: Yu
authors.forename: Jing
authors.initials: J
authors.lastname: Chen
authors.forename: Jichun
authors.initials: J
authors.lastname: Chen
authors.forename: Xigui
authors.initials: X
authors.lastname: Wu
authors.forename: Jianfeng
authors.initials: J
authors.lastname: Huang
authors.forename: Jiang
authors.initials: J
authors.lastname: He
authors.forename: Dongfeng
authors.initials: D
authors.lastname: Gu
mesh_terms: D000328:Adult; D000368:Aged; D001794:Blood Pressure / Q000502:physiology; D002681:China / Q000453:epidemiology; D015331:Cohort Studies; D003327:Coronary Disease / Q000453:epidemiology / Q000209:etiology*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D006973:Hypertension / Q000150:complications*; D008875:Middle Aged; D012306:Risk; D012907:Smoking / Q000009:adverse effects* / Q000453:epidemiology / Q000523:psychology; D013599:Systole / Q000502:physiology; D016387:Women's Health