title: The relationship between waterpipe and cigarette smoking in low and middle income countries: cross-sectional analysis of the global adult tobacco survey.
abstract: BACKGROUND
  Waterpipe tobacco smoking is receiving growing attention due to accumulating evidence suggesting increasing prevalence in some populations and deleterious health effects. Nevertheless, the relationship between waterpipe and cigarette smoking remain unknown, particularly in low and middle income countries.
  
  
  METHODS
  We analysed waterpipe and cigarette smoking using data from Global Adult Tobacco Survey, a household survey of adults aged ≥15 years conducted between 2008-2010 in LMICs. Factors associated with waterpipe and cigarette use were assessed using multiple logistic regression. Factors associated with the quantity of waterpipe and cigarette smoking were assessed using log-linear regression models.
  
  
  RESULTS
  After adjusting for age, gender, residence, education, occupation and smokeless tobacco use, waterpipe smoking was significantly higher among cigarette users than in non-cigarette users in India (5.6% vs. 0.6%, AOR 13.12, 95% CI 7.41-23.23) and Russia (6.7% vs. 0.2%, AOR 27.73, 95% CI 11.41-67.43), but inversely associated in Egypt (2.6% vs. 3.4%, AOR 0.21, 95% CI 0.15-0.30) and not associated in Vietnam (13.3% vs. 4.7%, AOR 0.96, 95% CI 0.74-1.23). Compared to non-cigarette smokers, waterpipe smokers who also used cigarettes had more waterpipe smoking sessions per week in Russia (1.3 vs. 2.9, beta coefficient 0.31, 95% CI 0.06, 0.57), but less in Egypt (18.2 vs. 10.7, beta coefficient -0.45, 95% CI -0.73, -0.17) and Vietnam (102.0 vs. 79.3, beta coefficient -0.31, 95% CI -0.56, -0.06) and similar amounts in India (29.4 vs. 32.6, beta coefficient -0.12, 95% CI -0.46, 0.22).
  
  
  CONCLUSIONS
  Waterpipe smoking is low in most LMICs but important country-level differences in use, including concurrent cigarette smoking, should be taken into account when designing and evaluating tobacco control interventions.
authors.affiliation: Department of Primary Care and Public Health, School of Public Health, Imperial College London, London, United Kingdom.
authors.forename: Mohammed
authors.initials: M
authors.lastname: Jawad
authors.affiliation: Department of Primary Care and Public Health, School of Public Health, Imperial College London, London, United Kingdom.
authors.forename: John Tayu
authors.initials: JT
authors.lastname: Lee
authors.affiliation: Department of Primary Care and Public Health, School of Public Health, Imperial College London, London, United Kingdom; South Asia Network for Chronic Disease, Public Health Foundation of India, New Delhi, India.
authors.forename: Christopher
authors.initials: C
authors.lastname: Millett
mesh_terms: D000328:Adult; D000367:Age Factors; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D008297:Male; D012189:Retrospective Studies; D012737:Sex Factors; D012907:Smoking / Q000453:epidemiology*; D016540:Smoking Cessation; D012959:Socioeconomic Factors