title: Relationship between alcohol consumption and myocardial infarction among ageing men using a marginal structural model.
abstract: BACKGROUND
  Studies on the association between alcohol consumption and myocardial infarction (MI) have typically used baseline data on alcohol consumption and potential confounders. This study aimed at investigating the association between alcohol consumption and MI considering time-varying alcohol consumption and time-varying confounders.
  
  
  METHODS
  Data were available for 1030 males participating in the Kuopio Ischaemic Heart Disease Risk Factor Study (Finland). Baseline data for the present study were collected in 1991-93. MIs were ascertained from national registries until December 2005. Alcohol consumption was categorized into four groups. Data were analysed using conventional discrete-time hazard and marginal structural models (MSMs). Time-invariant covariates were age, working status, diabetes and cigarette-years. Time-varying covariates in the MSM were prior alcohol consumption, smoking, history of cardiovascular diseases, body mass index, high-density lipoprotein cholesterol, systolic blood pressure, insulin and fibrinogen.
  
  
  RESULTS
  An insignificant increase of MI risk among the heaviest alcohol consumers (≥168 g week(-1)) compared with the reference group (12-83 g week(-1)) was observed when using a conventional model including baseline alcohol consumption and confounders measured prior to baseline [relative risk (RR) = 1.20, 95% confidence interval (95% CI) = 0.68-2.12]. When using a conventional model with time-varying alcohol consumption and adjusting for prior confounders, an increased risk of MI among the heaviest alcohol consumers was revealed (RR = 1.71, 95% CI = 1.03-2.85). There was also a trend towards increased risk among the heaviest consumers using the MSM (RR = 1.59, 95% CI = 0.93-2.72).
  
  
  CONCLUSIONS
  Our findings suggest that standard methods using only baseline data on alcohol consumption and confounders may lead to biased estimates on the association between alcohol consumption and MI.
authors.affiliation: Institute of Public Health and Clinical Nutrition, University of Eastern Finland, Kuopio, Finland. jenni.ilomaki@uef.fi
authors.forename: Jenni
authors.initials: J
authors.lastname: Ilomäki
authors.forename: Anjum
authors.initials: A
authors.lastname: Hajat
authors.forename: Jussi
authors.initials: J
authors.lastname: Kauhanen
authors.forename: Sudhir
authors.initials: S
authors.lastname: Kurl
authors.forename: Jay S
authors.initials: JS
authors.lastname: Kaufman
authors.forename: Tomi-Pekka
authors.initials: TP
authors.lastname: Tuomainen
authors.forename: Maarit Jaana
authors.initials: MJ
authors.lastname: Korhonen
mesh_terms: D000375:Aging / Q000502:physiology*; D000428:Alcohol Drinking / Q000453:epidemiology*; D015992:Body Mass Index; D005387:Finland / Q000453:epidemiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000453:epidemiology*; D016016:Proportional Hazards Models; D012042:Registries; D012307:Risk Factors; D012907:Smoking