title: Tobacco smoking and acute myocardial infarction in young adults: a population-based case-control study.
abstract: OBJECTIVE
  To evaluate the effect of tobacco smoking on the risk of non-fatal acute myocardial infarction in young adults (< or = 45 years), and whether there is modification of this effect by sex.
  
  
  METHODS
  We conducted a population-based case-control study with 329 incident acute myocardial infarction cases (42 women; 287 men), consecutively admitted to the Cardiology department of hospitals in Porto, Portugal, and 778 controls (486 women; 292 men), selected within the non-institutionalized Porto population, during 2001-2003. Odds ratios and 95% confidence intervals (OR, 95%CI) were calculated using unconditional logistic regression.
  
  
  RESULTS
  The prevalence of current smoking was 80.8% in male cases and 53.8% in male controls (OR=3.63, 95%CI: 2.50, 5.27) and 59.5% of female cases were smokers compared to 35.8% of controls (OR=2.64, 95%CI: 1.39, 5.02). No interaction was found between current smoking and sex on myocardial infarction risk (p=0.401). A dose-effect response was present, the odds favoring myocardial infarction reaching an eight-fold increase for those that smoked > 25 cigarettes/day compared to never smokers. The risk estimate for former smokers was similar to never smokers.
  
  
  CONCLUSIONS
  Tobacco smoking is an important independent risk factor for acute myocardial infarction in young adults, with similar strength of association for both sexes.
authors.affiliation: Department of Hygiene and Epidemiology, University of Porto Medical School, Alameda Prof. Hernâni Monteiro, 4200-319, Porto, Portugal. acmatos@med.up.pt
authors.forename: Andreia
authors.initials: A
authors.lastname: Oliveira
authors.forename: Henrique
authors.initials: H
authors.lastname: Barros
authors.forename: Maria Júlia
authors.initials: MJ
authors.lastname: Maciel
authors.forename: Carla
authors.initials: C
authors.lastname: Lopes
mesh_terms: D000208:Acute Disease; D000293:Adolescent; D000328:Adult; D016507:Cardiology Service, Hospital / Q000706:statistics & numerical data; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D015994:Incidence; D016015:Logistic Models; D008297:Male; D009203:Myocardial Infarction / Q000453:epidemiology*; D016017:Odds Ratio; D011174:Portugal / Q000453:epidemiology; D018570:Risk Assessment; D012307:Risk Factors; D012309:Risk-Taking; D012737:Sex Factors; D012907:Smoking / Q000453:epidemiology*