title: Interaction of smoking and metabolic syndrome on cardiovascular risk in a Chinese cohort.
abstract: BACKGROUND
  The high prevalence of smoking and metabolic syndrome (MS) and increased incidence of cardiovascular disease (CVD) in China indicates that there may be an interaction between smoking and MS on cardiovascular risk. Therefore, we aimed to examine the independent and combined effects of smoking and MS on risk of CVD in a Chinese cohort.
  
  
  METHODS
  We analyzed data from a population-based prospective cohort of 3598 participants aged 35-74 years from Jiangsu China who were free of diabetes and CVD at enrollment and were followed for cardiovascular events (including myocardial infarction, ischemic stroke, hemorrhagic stroke, and cardiovascular mortality) until 31 August 2008.
  
  
  RESULTS
  During 8 years (median 6.3 years) of follow-up, 82 participants developed CVD. After adjusting for age, sex, body mass index, alcohol consumption, family history of cardiovascular disease and MS, smoking significantly increased cardiovascular risk in a dose-response manner. After further adjustment for smoking status, the hazard ratio of CVD for participants with MS was 2.49 (95% confidence interval 1.59-3.90) compared with those without the syndrome. There was a statistically significant additive interaction between current smoking and MS on cardiovascular risk. The risk of CVD for current smokers with MS was 1.81 times as high as the sum of risks in participants with a single condition alone.
  
  
  CONCLUSIONS
  Both cigarette smoking and MS are strong risk factors of CVD in the Chinese population. Moreover, this study further demonstrates an additive interaction of current smoking and MS on cardiovascular risk.
authors.affiliation: Department of Epidemiology, School of Public Health, Soochow University, Suzhou, China.
authors.forename: Lijun
authors.initials: L
authors.lastname: Zhang
authors.forename: Zhirong
authors.initials: Z
authors.lastname: Guo
authors.forename: Ming
authors.initials: M
authors.lastname: Wu
authors.forename: Xiaoshu
authors.initials: X
authors.lastname: Hu
authors.forename: Yanying
authors.initials: Y
authors.lastname: Xu
authors.forename: Zhengyuan
authors.initials: Z
authors.lastname: Zhou
mesh_terms: D000328:Adult; D000368:Aged; D044466:Asian People / Q000208:ethnology*; D002318:Cardiovascular Diseases / Q000175:diagnosis* / Q000208:ethnology*; D015331:Cohort Studies; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D024821:Metabolic Syndrome / Q000175:diagnosis* / Q000208:ethnology*; D008875:Middle Aged; D011159:Population Surveillance / Q000379:methods; D011446:Prospective Studies; D012307:Risk Factors; D012907:Smoking / Q000208:ethnology*