title: Does body mass index impact on the relationship between systolic blood pressure and cardiovascular disease?: meta-analysis of 419 488 individuals from the Asia pacific cohort studies collaboration.
abstract: OBJECTIVE
  Elevated blood pressure and excess body mass index (BMI) are established risk factors for cardiovascular disease (CVD) but controversy exists as to whether, and how, they interact.
  
  
  METHODS
  The interactions between systolic blood pressure and BMI on coronary heart disease, ischemic and hemorrhagic stroke and CVD were examined using data from 419 448 participants (≥ 30 years) in the Asia-Pacific region. BMI was categorized into 5 groups, using standard criteria, and systolic blood pressure was analyzed both as a categorical and continuous variable. Cox proportional hazard models, stratified by sex and study, were used to estimate hazard ratios, adjusting for age and smoking and the interaction was assessed by likelihood ratio tests.
  
  
  RESULTS
  During 2.6 million person-years of follow-up, there were 10 877 CVD events. Risks of CVD and subtypes increased monotonically with increasing systolic blood pressure in all BMI subgroups. There was some evidence of a decreasing hazard ratio, per additional 10 mm Hg systolic blood pressure, with increasing BMI, but the differences, although significant, are unlikely to be of clinical relevance. The hazard ratio for CVD was 1.34 (95% CI, 1.32-1.36) overall with individual hazard ratios ranging between 1.28 and 1.36 across all BMI groups. For coronary heart disease, ischemic stroke, and hemorrhagic stroke, the overall hazard ratios per 10 mm Hg systolic blood pressure were 1.24, 1.46, and 1.65, respectively.
  
  
  CONCLUSIONS
  Increased blood pressure is an important determinant of CVD risk irrespective of BMI. Although its effect tends to be weaker in people with relatively high BMI, the difference is not sufficiently great to warrant alterations to existing guidelines.
authors.affiliation: Professorial Unit, The George Institute for Global Health, University of Sydney, PO Box M201, Missenden Road, NSW 2050, Australia.
authors.forename: Rumi
authors.initials: R
authors.lastname: Tsukinoki
authors.forename: Yoshitaka
authors.initials: Y
authors.lastname: Murakami
authors.forename: Rachel
authors.initials: R
authors.lastname: Huxley
authors.forename: Takayoshi
authors.initials: T
authors.lastname: Ohkubo
authors.forename: Xianghua
authors.initials: X
authors.lastname: Fang
authors.forename: Il
authors.initials: I
authors.lastname: Suh
authors.forename: Hirotsugu
authors.initials: H
authors.lastname: Ueshima
authors.forename: Tai-Hing
authors.initials: TH
authors.lastname: Lam
authors.forename: Mark
authors.initials: M
authors.lastname: Woodward
mesh_terms: D000328:Adult; D000368:Aged; D001210:Asia, Southeastern / Q000453:epidemiology; D001794:Blood Pressure; D015992:Body Mass Index; D002318:Cardiovascular Diseases / Q000453:epidemiology / Q000503:physiopathology*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D016016:Proportional Hazards Models; D012307:Risk Factors