Death-knell for BMI measure after no link found to CVD
Body mass index could be scrapped as a measure of obesity after a major new meta-analysis found it was useless for predicting cardiovascular disease and death.
Patients with heart disease who were classed by BMIs as overweight or slightly obese actually lived longer than those with a normal BMI, concluded the analysis of 40 studies involving 250,000 patients.
The widely-used measure fails to discriminate between muscle and fat and should be replaced by alternatives like waist-to-hip ratio, the research-ers report in The Lancet.
An accompanying commentary said the findings meant BMI can 'definitely be left aside as a measure of cardiovascular risk for both primary and secondary prevention'.
It called for an overhaul of current guidance and GP risk management tools.
Patients with a BMI under 20 had a 37 per cent greater risk for total and cardiovascular mortality than with those with a normal BMI.
Patients classed as obese by BMI had no increased risk for either total or cardiovascular mortality over an average follow-up of 3.8 years. Even patients with severe obesity by BMI did not have an increase in total mortality, although they did have the highest cardiovascular mortality.
Study leader Dr Francisco Lopez-Jimenez, managing director of the division of cardiovascular diseases at the Mayo clinic in Florida, said: 'A low BMI is strongly associated with an increased long-term risk of total mortality. Rather than proving obesity is harmless, our data suggest alternative methods might be needed.'
Dr John Ashcroft, CHD lead for Erewash PCT and a GP in Ilkeston, Derbyshire, said: 'You wonder how many nails in the coffin it is going to take before BMI is put to rest. Just a GP looking at their a patient and asking "Are they fat?'' is the most simple
and arguably effective indicator.'
In the same week, the landmark EPIC study added pressure for a change in guidance. An analysis due to be presented at an international obesity conference in Sydney, Australia, found waist-to-hip ratio was much more strongly related to incidence of coronary heart disease than BMI.