title: Obesity, metabolic syndrome and risk of atrial fibrillation: a Swedish, prospective cohort study.
abstract: OBJECTIVE
  We aimed to investigate whether different measures of obesity could similarly predict atrial fibrillation, and whether the atrial fibrillation risk associated with obesity is dependent on presence of metabolic syndrome.
  
  
  METHODS
  We performed our study in a population-based longitudinal cardiovascular study, comprising 1 924 men and 2 097 women, aged 60 years, from Stockholm. Body mass index, waist circumference, sagittal abdominal diameter and components of metabolic syndrome (systolic- and diastolic blood pressure, fasting glucose, triglycerides, high-density lipoprotein-cholesterol) were recorded at baseline. Participants were classified by their body mass index (normal weight, overweight or obese), waist circumference (normal, semi-elevated or elevated), and according to presence of metabolic syndrome. Atrial fibrillation risk was estimated by Cox proportional hazards regression models, adjusted for common atrial fibrillation risk factors, expressed as HR and 95% CI.
  
  
  RESULTS
  During a mean follow-up of 13.6 years, 285 incident atrial fibrillation cases were recorded. One standard deviation increment of each obesity measure was associated with increased atrial fibrillation risk as: body mass index 1.25 (1.12 - 1.40), waist circumference 1.35 (1.19 - 1.54) and sagittal abdominal diameter 1.28 (1.14 - 1.44). Compared to normal weight subjects without metabolic syndrome, increased atrial fibrillation risk was noted for overweight subjects with metabolic syndrome, 1.67 (1.16 - 2.41), obese subjects without metabolic syndrome, 1.75 (1.11 - 2.74) and obese subjects with metabolic syndrome, 1.92 (1.34 - 2.74). Compared to subjects with normal waist circumference without metabolic syndrome, subjects with elevated waist circumference and metabolic syndrome suffered increased atrial fibrillation risk, 2.03 (1.44 - 2.87).
  
  
  CONCLUSIONS
  Body mass index, waist circumference and sagittal abdominal diameter could similarly predict atrial fibrillation. Obesity was associated with an increased atrial fibrillation risk regardless of metabolic syndrome, whereas overweight and elevated waist circumference was associated with increased atrial fibrillation risk only if metabolic syndrome was present.
authors.affiliation: Unit of Cardiovascular Epidemiology, Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden.
authors.forename: Petter K
authors.initials: PK
authors.lastname: Nyström
authors.affiliation: Centre for Family Medicine, Department of Neurobiology, Care Sciences and Society, Karolinska Institutet, Huddinge, Sweden; Department of Medical Sciences, Molecular Epidemiology and Science for Life Laboratory, Uppsala University, Uppsala, Sweden.
authors.forename: Axel C
authors.initials: AC
authors.lastname: Carlsson
authors.affiliation: Unit of Cardiovascular Epidemiology, Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden.
authors.forename: Karin
authors.initials: K
authors.lastname: Leander
authors.affiliation: Unit of Cardiovascular Epidemiology, Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden; Department of Cardiology, Karolinska University Hospital, Stockholm, Sweden.
authors.forename: Ulf
authors.initials: U
authors.lastname: de Faire
authors.affiliation: Department of Cardiology, Karolinska University Hospital, Stockholm, Sweden.
authors.forename: Mai-Lis
authors.initials: ML
authors.lastname: Hellenius
authors.affiliation: Unit of Cardiovascular Epidemiology, Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden; Division of Cardiovascular Medicine, Department of Clinical Sciences, Danderyds Hospital, Karolinska Institutet, Stockholm, Sweden.
authors.forename: Bruna
authors.initials: B
authors.lastname: Gigante
mesh_terms: D001281:Atrial Fibrillation / Q000097:blood / Q000209:etiology* / Q000503:physiopathology; D001786:Blood Glucose / Q000502:physiology; D001794:Blood Pressure / Q000502:physiology; D015992:Body Mass Index; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008075:Lipoproteins, HDL / Q000097:blood; D008297:Male; D024821:Metabolic Syndrome / Q000097:blood / Q000150:complications* / Q000503:physiopathology; D008875:Middle Aged; D009765:Obesity / Q000097:blood / Q000150:complications* / Q000503:physiopathology; D011446:Prospective Studies; D012307:Risk Factors; D013548:Sweden; D014280:Triglycerides / Q000097:blood; D055105:Waist Circumference / Q000502:physiology
chemical_list: D001786:Blood Glucose; D008075:Lipoproteins, HDL; D014280:Triglycerides