- Prescribing Advice for GPs - https://www.prescriber.org.uk -

BMI and MI Risk

The Lancet has published a case control study1 that has looked at the relationship between Myocardial Infarction (MI) and markers of obesity including body mass index (BMI), waist and hip circumferences and waist-to-hip ratio.

The study showed that while BMI did show a graded association with MI, waist-to-hip ratio had a much stronger association. This adds to the growing evidence that BMI is less accurate as a predictor in some populations. The authors conclude that waist-to-hip ratio should be used as a marker for obesity, especially when used to calculate heart disease risks.

It is notable that the correlation was performed on MI risk and not cardiovascular disease risk. At this time it is not clear if there is also an association between waist-to-hip ratio and vascular outcomes other than MI.

Action: This debate is likely to continue until the evidence gives us greater clarity. BMI is still a useful indicator of obesity. Clinicians may wish to use waist-to-hip ratios in addition to BMI until clearer advice becomes available, although currently there is no read code for this information.


  1. Obesity and the risk of myocardial infarction in 27 000 participants from 52 countries: a case-control study. The Lancet 2005; 366:1640-1649