title: Body mass index and incident hospitalisation for cardiovascular disease in 158 546 participants from the 45 and Up Study.
abstract: OBJECTIVE
  To investigate the relationship between fine gradations in body mass index (BMI) and risk of hospitalisation for different types of cardiovascular disease (CVD).
  
  
  METHODS
  The 45 and Up Study is a large-scale Australian cohort study initiated in 2006. Self-reported data from 158 546 individuals with no history of CVD were linked prospectively to hospitalisation and mortality data. Hazard ratios (HRs) of incident hospitalisation for specific CVD diagnoses in relation to baseline BMI categories were estimated using Cox regression, adjusting for age, sex, region of residence, income, education, smoking, alcohol intake and health insurance status.
  
  
  RESULTS
  There were 9594 incident CVD admissions over 583 100 person-years among people with BMI≥20 kg m(-2), including 3096 for ischaemic heart disease (IHD), 1373 for stroke, 411 for peripheral vascular disease (PVD) and 320 for heart failure. The adjusted HR of hospitalisation for all CVD diagnoses combined increased significantly with increasing BMI (P(trend) <0.0001)). The HR of IHD hospitalisation increased by 23% (95% confidence interval (95% CI): 18-27%) per 5 kg m(-2) increase in BMI (compared to BMI 20.0-22.49 kg m(-2), HR (95% CI) for BMI categories were: 22.5-24.99=1.25 (1.08-1.44); 25-27.49=1.43 (1.24-1.65); 27.5-29.99=1.64 (1.42-1.90); 30-32.49=1.63 (1.39-1.91) and 32.5-50=2.10 (1.79-2.45)). The risk of hospitalisation for heart failure showed a significant, but nonlinear, increase with increasing BMI. No significant increase was seen with above-normal BMI for stroke or PVD. For other specific classifications of CVD, HRs of hospitalisation increased significantly with increasing BMI for: hypertension; angina; acute myocardial infarction; chronic IHD; pulmonary embolism; non-rheumatic aortic valve disorders; atrioventricular and left bundle-branch block; atrial fibrillation and flutter; aortic aneurysm; and phlebitis and thrombophlebitis.
  
  
  CONCLUSIONS
  The risk of hospitalisation for a wide range of CVD subtypes increases with relatively fine increments in BMI. Obesity prevention strategies are likely to benefit from focusing on bringing down the mean BMI at the population level, in addition to targeting those with a high BMI.
authors.affiliation: National Centre for Epidemiology and Population Health, The Australian National University, Canberra, ACT, Australia.
authors.forename: G
authors.initials: G
authors.lastname: Joshy
authors.affiliation: 1] National Centre for Epidemiology and Population Health, The Australian National University, Canberra, ACT, Australia [2] Australian Centre for Economic Research on Health, The Australian National University, Canberra, ACT, Australia.
authors.forename: R J
authors.initials: RJ
authors.lastname: Korda
authors.affiliation: Centre for Clinical Epidemiology and Biostatistics, University of Newcastle, and Hunter Medical Research Institute, Newcastle, NSW, Australia.
authors.forename: J
authors.initials: J
authors.lastname: Attia
authors.affiliation: 1] School of Public Health and Community Medicine, The University of New South Wales, Sydney, NSW, Australia [2] The Sax Institute, Sydney, NSW, Australia.
authors.forename: B
authors.initials: B
authors.lastname: Liu
authors.affiliation: Sydney School of Public Health, The University of Sydney, Sydney, NSW, Australia.
authors.forename: A E
authors.initials: AE
authors.lastname: Bauman
authors.affiliation: 1] National Centre for Epidemiology and Population Health, The Australian National University, Canberra, ACT, Australia [2] The Sax Institute, Sydney, NSW, Australia.
authors.forename: E
authors.initials: E
authors.lastname: Banks
mesh_terms: D000368:Aged; D001315:Australia / Q000453:epidemiology; D015992:Body Mass Index; D002318:Cardiovascular Diseases / Q000453:epidemiology / Q000209:etiology* / Q000503:physiopathology; D015331:Cohort Studies; D005260:Female; D005500:Follow-Up Studies; D006760:Hospitalization / Q000706:statistics & numerical data*; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000150:complications* / Q000453:epidemiology / Q000503:physiopathology; D011159:Population Surveillance; D011446:Prospective Studies; D012307:Risk Factors; D057566:Self Report; D012907:Smoking / Q000009:adverse effects* / Q000453:epidemiology / Q000503:physiopathology; D011795:Surveys and Questionnaires