title: The genetic correlation between cigarette smoking and alcohol drinking among Chinese adult male twins: an ordinal bivariate genetic analysis.
abstract: BACKGROUND
  Though multiple policies have been implemented, the cigarette control in China is still facing a great challenge. At the same time, alcohol drinking has increasingly become a public health problem. Considering cigarette smoking and alcohol drinking often co-occur, a few studies tested the covariance of these phenotypes. However, the genetic and environmental correlation between them among Chinese population has not been determined. The main aim of this study is to fill this gap.
  
  
  METHODS
  From the Chinese National Twin Registry, we obtained the data on cigarette smoking and alcohol drinking behaviors. The ordinal bivariate genetic analysis was performed to fit the categorical variables. After identifying the best decomposition among the Cholesky, common, and independent pathway model, we established the most parsimonious submodel.
  
  
  RESULTS
  The correlation between current tobacco and alcohol use could be explained by Cholesky model. The shared environmental variances for both phenotypes were dropped to construct the most parsimonious submodel. Furthermore, the most parsimonious submodel showed a moderate correlation (0.32, 95%CI=0.17-0.46) between the genetic components and a negligible non-shared environmental correlation.
  
  
  CONCLUSIONS
  As the first bivariate genetic analysis on current tobacco smoking and current alcohol drinking in China, this study suggested a common genetic vulnerability to tobacco and alcohol use in male twins. Further studies should be carried out to track the pertinent genes that are related to the comorbidity of smoking and drinking in Chinese population. Another urgent need is to recognize the behavior-specific environmental risk factors.
authors.affiliation: Department of Epidemiology and Biostatistics, School of Public Health, Peking University Health Science Center, Beijing, China.
authors.forename: Ting
authors.initials: T
authors.lastname: Zhang
authors.forename: Wenjing
authors.initials: W
authors.lastname: Gao
authors.forename: Weihua
authors.initials: W
authors.lastname: Cao
authors.forename: Siyan
authors.initials: S
authors.lastname: Zhan
authors.forename: Jun
authors.initials: J
authors.lastname: Lv
authors.forename: Zengchang
authors.initials: Z
authors.lastname: Pang
authors.forename: Shaojie
authors.initials: S
authors.lastname: Wang
authors.forename: Rongfu
authors.initials: R
authors.lastname: Chen
authors.forename: Yonghua
authors.initials: Y
authors.lastname: Hu
authors.forename: Liming
authors.initials: L
authors.lastname: Li
mesh_terms: D000328:Adult; D000428:Alcohol Drinking / Q000453:epidemiology / Q000235:genetics*; D016009:Chi-Square Distribution; D002681:China / Q000453:epidemiology; D059647:Gene-Environment Interaction; D020022:Genetic Predisposition to Disease; D006801:Humans; D016015:Logistic Models; D008297:Male; D008957:Models, Genetic; D010641:Phenotype; D012042:Registries; D012307:Risk Factors; D012907:Smoking / Q000453:epidemiology / Q000235:genetics*