European Journal of Epidemiology

, Volume 25, Issue 2, pp 95–102 | Cite as

Atrial fibrillation in the Malmö diet and cancer study: a study of occurrence, risk factors and diagnostic validity

  • J. Gustav Smith
  • Pyotr G. Platonov
  • Bo Hedblad
  • Gunnar Engström
  • Olle Melander
Cardiovascular Disease


The validity of atrial fibrillation (AF) diagnoses in national registers for use as endpoints in prospective studies has not been evaluated. We studied the validity of AF diagnoses in Swedish national hospital discharge and cause of death registers and the occurrence of and risk factors for AF in a middle-aged Swedish population using these registers. Our study included the 30,447 individuals (age 44–73) who attended baseline visits in 1991–1996 of the Malmö Diet and Cancer study. Individuals with a first AF diagnosis were identified by record linkage with national registers. A subset of cases was randomly selected for validation by examination of electrocardiograms and patient records. Electrocardiograms were available in 98% of the validation sample (95% definitive AF, 3% no AF). The 2% with ECGs unavailable had probable AF. Baseline AF prevalence was 1.3%, higher in men and increased with age. During 11.2 years of follow-up 1430 first AF diagnoses occurred. Risk factors were age, hypertension, BMI, diabetes, history of heart failure, history of myocardial infarction and, in men but not women, current smoking. The strongest risk factors were history of heart failure (hazard ratio men 4.5, women 8.7) and myocardial infarction (hazard ratio men 2.0, women 1.8). The largest population attributable risks were observed for hypertension (men 38%, women 34%) and obesity (men 11%, women 10%). In conclusion, case misclassification of AF in national registers is small, indicating feasibility of use in prospective studies. Hypertension and obesity account for large portions of population risk in middle-aged individuals with low prevalence of manifest cardiac disease.


Atrial fibrillation Epidemiology Cardiovascular risk factors Cohort study 



Atrial fibrillation




Population attributable risk


The Malmö Diet and Cancer Study


Body mass index


The Swedish Hospital Discharge Register


The Swedish Cause of Death Register


The International Classification of Diseases


Hazard ratio

95% CI

95% confidence interval



MDCS was made possible by grants from the Malmö city council. J. Gustav Smith gratefully acknowledges financial support from the Swedish Heart Lung Foundation. Pyotr Platonov was supported by governmental funding for clinical research within the Swedish NHS. Olle Melander was supported by grants from the Swedish Medical Research Council, the Swedish Heart and Lung Foundation, the Medical Faculty of Lund University, Malmö University Hospital, the Albert Påhlsson Research Foundation, the Crafoord foundation, the Ernhold Lundströms Research Foundation, the Region Skane, the Hulda and Conrad Mossfelt Foundation, the King Gustaf V and Queen Victoria Foundation, the Lennart Hanssons Memorial Fund, the Wallenberg Foundation.


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Copyright information

© Springer Science+Business Media B.V. 2009

Authors and Affiliations

  • J. Gustav Smith
    • 1
    • 2
    • 3
  • Pyotr G. Platonov
    • 2
  • Bo Hedblad
    • 1
  • Gunnar Engström
    • 1
  • Olle Melander
    • 1
  1. 1.Department of Clinical SciencesLund UniversityMalmöSweden
  2. 2.Department of Clinical SciencesLund UniversityLundSweden
  3. 3.Program in Medical and Population GeneticsBroad Institute of Harvard and Massachusetts Institute of TechnologyCambridgeUSA

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