title: The impact of body mass index on the associations of lipids with the risk of coronary heart disease in the Asia Pacific region.
abstract: OBJECTIVE
  To assess whether body mass index (BMI) modifies the associations of lipids with coronary heart disease (CHD).
  
  
  METHODS
  In the Asia Pacific Cohort Studies Collaboration, total cholesterol (TC), high density lipoprotein cholesterol (HDLC) and triglycerides (TG) were measured for 333,297, 71,777 and 84,015 participants, respectively. All participants had measured BMI, categorized into underweight, normal, high-normal, overweight and obese, using standard definitions. For each BMI subgroup the effects of lipids on CHD were estimated per 1 standard deviation (SD) increase using Cox proportional hazard models, stratified by study and sex, adjusted for age and smoking. They were compared across the BMI groups, testing for interactions.
  
  
  RESULTS
  In the analyses for TC, HDLC and TG, there were 3121, 714 and 808 CHD events during a mean follow-up of 6.7 years. The risk of CHD increased monotonically with increasing TC and decreasing HDLC in all BMI subgroups without evidence of heterogeneity (p for interaction > 0.4). In contrast, the hazard ratio for CHD for a one SD increase in log-transformed TG increased from 1.07 (95%CI 0.72-1.59) in underweight, 1.26 (1.10-1.44) in normal weight, 1.27 (1.08-1.49) in high-normal weight, 1.37 (1.22-1.55) in overweight, to 1.61(1.30-1.99) in obesity (p = 0.01 for interaction trend). These associations were attenuated (p = 0.07 for interaction) but remained significant in the overweight and obese after further adjustment for TC and HDLC.
  
  
  CONCLUSIONS
  Greater excess body weight exacerbated the effects of TG, but not TC or HDLC, on CHD, suggesting that additional effort is required to reduce TG in the overweight and obese.
authors: The George Institute for Global Health, University of Sydney, Australia.
authors: Yoichiro
authors: Y
authors: Hirakawa
authors: School of Public Health, The University of Hong Kong, Hong Kong, China.
authors: Tai-Hing
authors: TH
authors: Lam
authors: Department of Medicine and Pharmacology, University of Western Australia, Nedlands, Australia.
authors: Timothy
authors: T
authors: Welborn
authors: Cardiovascular and Metabolic Diseases Etiology Research Center, Department of Preventive Medicine, Yonsei University College of Medicine, Seoul, South Korea.
authors: Hyeon Chang
authors: HC
authors: Kim
authors: School of Public Health and Primary Care, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong, China.
authors: Suzanne
authors: S
authors: Ho
authors: Evidence-Based Medical Center, Xuanwu Hospital, Capital Medical University, Beijing, China.
authors: Xianghua
authors: X
authors: Fang
authors: Department of Public Health, Center for Epidemiologic Research in Asia, Shiga University of Medical Science, Japan.
authors: Hirotsugu
authors: H
authors: Ueshima
authors: Department of Preventive Medicine, Yonsei University College of Medicine, Seoul, South Korea.
authors: Il
authors: I
authors: Suh
authors: Cancer Epidemiology Centre, The Cancer Council, Victoria, Australia.
authors: Graham
authors: G
authors: Giles
authors: The George Institute for Global Health, University of Sydney, Australia; The George Institute for Global Health, Nuffield Department of Population Health, University of Oxford, UK; Department of Epidemiology, Johns Hopkins University, Baltimore, MD, USA.
authors: Mark
authors: M
authors: Woodward
keywords: Body mass index; Coronary heart disease; Dyslipidemias; Effect modification; Pooled analysis