A study, published in The Lancet, has shown that waist-to-hip ratio, not body mass index ( BMI ), is the best obesity measure for assessing the risk of heart attack.

If obesity is redefined using waist-to-hip ratio instead of BMI the proportion of people at risk of heart attack increases by threefold, according to authors.

Previous research has shown that obesity increases the risk of heart disease. However, these studies have mainly been done in populations of European and North American origin. The evidence for other populations is therefore sparse.

In the latest study, Salim Yusuf, at McMaster University and Hamilton Health Sciences, and colleagues aimed to assess whether other markers for obesity, especially waist-to-hip ratio, would be a stronger predictor of heart attack than the conventional measure of BMI in different ethnic populations.

The investigators looked at BMI, waist-to-hip ratio, waist measure, and hip measure in more than 27,000 people from 52 countries.
Half the participants had previously had a heart attack and half were age and sex-matched controls ( individuals who had not had a heart attack and were the same age and sex as cases ).

Researchers found that BMI was only slightly higher in heart attack patients than in controls, with no difference in the Middle East and South Asia. By contrast, heart attack patients had a strikingly higher waist-to-hip ratio than controls, irrespective of other cardiovascular risk factors.
This observation was consistent in men and women, across all ages, and in all regions of the world.

According to authors, waist-to-hip ratio is three times stronger than BMI in predicting the risk of a heart attack. Larger waist size ( which reflects the amount of abdominal fat ) was harmful, whereas larger hip size ( which may indicate the amount of lower body muscle ) was protective.

The waist-to-hip ratio is calculated by dividing the waist measure by the hip measure.
The cut off point for cardiovascular risk factors is less than 0.85 for women and 0.90 for men. A higher number denotes more risk

Yusuf concludes: " Our findings suggest that substantial reassessment is needed of the importance of obesity for cardiovascular disease in most regions of the world."

In an accompanying published comment Charlotte Krageland of the University of Oslo, Norway states: " The main message from the new report is that current practice with body mass index as the measure of obesity is obsolete. For the assessment of risk associated with obesity, the waist-to-hip ratio, and not the body mass index, is the preferred simple measure."

Source: McMaster University, 2005


XagenaMedicine2005