Obesity and the risk of myocardial infarction in 27,000 participants from 52 countries: a case-control study.
BACKGROUND
Obesity is a major risk factor for cardiovascular disease, but the most predictive measure for different ethnic populations is not clear. We aimed to assess whether markers of obesity, especially waist-to-hip ratio, would be stronger indicators of myocardial infarction than body-mass index (BMI), the conventional measure.


METHODS
We did a standardised case-control study of acute myocardial infarction with 27 098 participants in 52 countries (12,461 cases and 14,637 controls) representing several major ethnic groups. We assessed the relation between BMI, waist and hip circumferences, and waist-to-hip ratio to myocardial infarction overall and for each group.


RESULTS
BMI showed a modest and graded association with myocardial infarction (OR 1.44, 95% CI 1.32-1.57 top quintile vs bottom quintile before adjustment), which was substantially reduced after adjustment for waist-to-hip ratio (1.12, 1.03-1.22), and non-significant after adjustment for other risk factors (0.98, 0.88-1.09). For waist-to-hip ratio, the odds ratios for every successive quintile were significantly greater than that of the previous one (2nd quintile: 1.15, 1.05-1.26; 3rd quintile: 1.39; 1.28-1.52; 4th quintile: 1.90, 1.74-2.07; and 5th quintiles: 2.52, 2.31-2.74 [adjusted for age, sex, region, and smoking]). Waist (adjusted OR 1.77; 1.59-1.97) and hip (0.73; 0.66-0.80) circumferences were both highly significant after adjustment for BMI (p<0.0001 top vs bottom quintiles). Waist-to-hip ratio and waist and hip circumferences were closely (p<0.0001) associated with risk of myocardial infarction even after adjustment for other risk factors (ORs for top quintile vs lowest quintiles were 1.75, 1.33, and 0.76, respectively). The population-attributable risks of myocardial infarction for increased waist-to-hip ratio in the top two quintiles was 24.3% (95% CI 22.5-26.2) compared with only 7.7% (6.0-10.0) for the top two quintiles of BMI.


CONCLUSIONS
Waist-to-hip ratio shows a graded and highly significant association with myocardial infarction risk worldwide. Redefinition of obesity based on waist-to-hip ratio instead of BMI increases the estimate of myocardial infarction attributable to obesity in most ethnic groups.
Yusuf
Salim
S
Population Health Research Institute, McMaster University and Hamilton Health Sciences, Hamilton, Canada. yusufs@mcmaster.ca
Hawken
Steven
S
Ounpuu
Stephanie
S
Bautista
Leonelo
L
Franzosi
Maria Grazia
MG
Commerford
Patrick
P
Lang
Chim C
CC
Rumboldt
Zvonko
Z
Onen
Churchill L
CL
Lisheng
Liu
L
Tanomsup
Supachai
S
Wangai
Paul
P
Razak
Fahad
F
Sharma
Arya M
AM
Anand
Sonia S
SS
D000328:Adult; D015992:Body Mass Index; D016022:Case-Control Studies; D005260:Female; D014943:Global Health; D006801:Humans; D008297:Male; D009203:Myocardial Infarction / Q000209:etiology*; D009765:Obesity / Q000150:complications* / Q000453:epidemiology; D012307:Risk Factors; D049629:Waist-Hip Ratio