Watch your waist – Not just your weight

New research suggests that a simple tape measure may be an important – and easy – tool to assess your risk of developing heart disease. Studies show that where you carry your body weight – not just how much you weigh – helps to determine your risk.

What about the Body Mass Index (BMI)?
For a long time, doctors and researchers have used the Body Mass Index (BMI) to determine who is at a healthy weight and who isn’t. The BMI is calculated by dividing your weight by the square of your height (see box).

But it is difficult to apply the BMI as an accurate measure for all people. For instance, muscular people, such as football players, or people with larger frames (bigger bones) can have a high BMI, even though they are not overweight.

In fact, there are a number of people for whom the BMI is not considered accurate (children, and seniors, as well as women who are pregnant or breastfeeding). Perhaps the biggest drawback is that it doesn’t seem to be a good predictor for heart disease among non-Caucasian populations.

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Body Mass Index
How do you calculate it? Divide your weight in kilograms by the square of your height in metres. What does it mean? <18.5 Underweight 18.5– 24.9 Normal weight 25.0 – 29.9 Overweight 30.0 or more Obese

How does your Waist-to-Hip Ratio (WHR) measure up?
In a study of over 26,000 people in 52 countries, Hamilton-based researcher Dr. Yusuf and his colleagues found that a measurement called the Waist to Hip Ratio (WHR) was a much better indicator of heart risk than the BMI. Results showed that the WHR is an effective method of measurement because it reflects your own personal shape.

People with a healthy WHR tend to store excess weight on their hips, thighs and buttocks. In lay terms, we call this being pear-shaped. Alternatively, people with an unhealthy WHR carry excess weight in their middle – what doctors call central or abdominal obesity, more commonly referred to as being apple-shaped.

People who carry their weight around the middle are at increased risk of diabetes, high blood pressure and high cholesterol – all of which can cause your risk of heart disease to soar.

Waist to Hip Ratio (WHR)

What is it? The circumference of your waist divided by the circumference of your hips. How do I measure my waist and hips? Measure your natural waist where it is the smallest, usually at or just above your navel. Measure your hips at the widest part of your buttocks. What does it mean? Risk of heart disease increases as WHR increases. There is some variation between health agencies as to what is considered a healthy cut-off. For women, a healthy WHR is usually considered to be equal to or less than 0.80. For men, a healthy WHR is usually equal to or less than 0.90.

Waist Circumference
In Caucasian populations, waist circumference has been found to be as accurate an indicator of heart health risk as WHR. Like the WHR, waist circumference is an indicator of whether you are pear or apple-shaped. Whether waist circumference is as good a predictor for heart disease risk as WHR among non-Caucasian populations has yet to be determined.

The Bottom Line
If you find your WHR doesn’t make the grade, don’t despair. Research shows that losing as little as 5 per cent to 10 per cent of your body weight can help to reduce your risk of heart disease by as much as 35 per cent.

Sources:
Yusuf S et al. Obesity and the risk of myocardial infarction in 27,000 participants from 52 countries: a case-control study. Lancet 2005;366:1589-1591, 1640-1649
Information on BMI cut-offs and waist circumference: Canadian Guidelines for Body Weight Classification in Adults. http://www.hc-sc.gc.ca/fn-an/nutrition/weights-poids/guide-ld-adult/cg_quick_ref-ldc_rapide_ref_e.html
http://www.nlm.nih.gov/medlineplus/mplusdictionary.html
Cut-offs for WHR: Statistics Canada (Are You An Apple or a Pear?) – 0.80 for women and 0.95 for men; elsewhere on Health Canada site it is given as 0.80 for women and 1.00 for men http://www.hc-sc.gc.ca/fn-an/nutrition/weights-poids/vitalit/apple_pear-pomme_poire_e.html;
CBC News report – 0.85 for women and 0.90 for men Waist-hip ratio best measure of heart attack risk. http://www.cbc.ca/story/science/national/2005/11/03/waist-hip051103.html;
Canadian Living report – 0.85 for women and 0.90 for men Waist to hip ratio beats BMI. http://www.canadianliving.com/CanadianLiving/client/en/Health/DetailNews.asp?idNews=233032&idSM=76;
Sunday Times article http://www.timesonline.co.uk/article/0,,2-1857132,00.html – reports cut-offs are 0.85 for women and 0.90 for men, but also says British Heart Foundation has “more generous” cut-offs of 0.90 for women and 1.00 for men.
Effect of weight loss on CHD risk: Eilat-Adar S, Eldar M, Goldbourt U. Association of intentional changes in body weight with coronary heart disease event rates in overweight subjects who have an additional coronary risk factor. Am J Epidemiology 2005;151:352-8

Provided by www.quakerheart.ca – an online resource designed to help empower Canadian women to take charge of their heart health and inspire heart healthy living for those around them.