title: The effect of leisure-time physical activity on the risk of acute myocardial infarction depending on body mass index: a population-based case-control study.
abstract: BACKGROUND
  High body mass index (BMI) and lack of physical activity have been recognized as important risk factors for coronary heart disease. The aim of the present study was to evaluate whether leisure-time physical activity compensates for the increased risk of acute myocardial infarction associated with overweight and obesity.
  
  
  METHODS
  Data from the SHEEP (Stockholm Heart Epidemiology Program) study were used. The SHEEP study is a large Swedish population-based case-control study, comprising 1204 male and 550 female cases, and 1538 male and 777 female controls, conducted in Stockholm County, Sweden, during the period 1992-1994. Odds ratios (OR), together with 95 % confidence intervals (95% CI), were calculated using unconditional logistic regression, as estimates of the relative risks.
  
  
  RESULTS
  Regular leisure-time physical activity was associated with a decreased risk of myocardial infarction among lean, normal-weight and overweight subjects, but not among obese subjects. Obese (BMI > or = 30) and physically active persons had an almost twofold risk of myocardial infarction, compared with normal-weight and sedentary persons (OR 1.85, 95% CI 1.07-3.18). The results were similar for men and women.
  
  
  CONCLUSIONS
  While regular leisure-time physical activity seems to provide protection against myocardial infarction among lean, normal-weight and overweight subjects, this does not appear to be the case in obese subjects.
authors.affiliation: Division of Cardiovascular Epidemiology, Institute of Environmental Medicine, Karolinska Institutet, Box 210, SE-171 77 Stockholm, Sweden. eleonor.fransson@ki.se
authors.forename: Eleonor
authors.initials: E
authors.lastname: Fransson
authors.forename: Ulf
authors.initials: U
authors.lastname: de Faire
authors.forename: Anders
authors.initials: A
authors.lastname: Ahlbom
authors.forename: Christina
authors.initials: C
authors.lastname: Reuterwall
authors.forename: Johan
authors.initials: J
authors.lastname: Hallqvist
authors.forename: Lars
authors.initials: L
authors.lastname: Alfredsson
mesh_terms: D000208:Acute Disease; D000368:Aged; D015992:Body Mass Index; D016022:Case-Control Studies; D015444:Exercise / Q000502:physiology*; D005260:Female; D006801:Humans; D007899:Leisure Activities; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D009043:Motor Activity / Q000502:physiology*; D009203:Myocardial Infarction / Q000453:epidemiology* / Q000517:prevention & control; D009765:Obesity / Q000503:physiopathology; D050177:Overweight; D018570:Risk Assessment; D012307:Risk Factors; D013548:Sweden / Q000453:epidemiology