title: Applied Prevalence Ratio estimation with different Regression models: An example from a cross-national study on substance use research.
abstract: OBJECTIVE
  To examine the differences between Prevalence Ratio (PR) and Odds Ratio (OR) in a cross-sectional study and to provide tools to calculate PR using two statistical packages widely used in substance use research (STATA and R).
  
  
  METHODS
  We used cross-sectional data from 41,263 participants of 16 European countries participating in the Survey on Health, Ageing and Retirement in Europe (SHARE). The dependent variable, hazardous drinking, was calculated using the Alcohol Use Disorders Identification Test - Consumption (AUDIT-C). The main independent variable was gender. Other variables used were: age, educational level and country of residence. PR of hazardous drinking in men with relation to women was estimated using Mantel-Haenszel method, log-binomial regression models and poisson regression models with robust variance. These estimations were compared to the OR calculated using logistic regression models.
  
  
  RESULTS
  Prevalence of hazardous drinkers varied among countries. Generally, men have higher prevalence of hazardous drinking than women [PR=1.43 (1.38-1.47)]. Estimated PR was identical independently of the method and the statistical package used. However, OR overestimated PR, depending on the prevalence of hazardous drinking in the country.
  
  
  CONCLUSIONS
  In cross-sectional studies, where comparisons between countries with differences in the prevalence of the disease or condition are made, it is advisable to use PR instead of OR.
authors.affiliation: Agència de Salut Pública de Barcelona. Departament de Psicobiologia i de Metodologia de les Ciències de la Salut, Universitat Autònoma de Barcelona. CIBER de Epidemiología y Salud Pública (CIBERESP), Instituto de Salud Carlos III. Institut d'Investigació Biomèdica de Sant Pau.. aespelt@aspb.cat.
authors.forename: Albert
authors.initials: A
authors.lastname: Espelt
authors.forename: Marc
authors.initials: M
authors.lastname: Marí-Dell'Olmo
authors.forename: Eva
authors.initials: E
authors.lastname: Penelo
authors.forename: Marina
authors.initials: M
authors.lastname: Bosque-Prous
mesh_terms: D003430:Cross-Sectional Studies; D005060:Europe / Q000453:epidemiology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D016017:Odds Ratio; D015995:Prevalence; D012044:Regression Analysis; D019966:Substance-Related Disorders / Q000453:epidemiology*