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Tools to assess your health risk

A woman  measures her waist with a tape measure.

Using body weight to assess your overall health risk

Two tools can be used to assess the general health risk that may be linked to your body size: 1) waist circumference
(the distance around your waist) is used to assess general health risk and 2) body mass index (BMI) gives you an idea of how healthy you are based on your body weight in relation to your height. Used together, these two tools give the best idea of your overall health risk.

1. Waist circumference

Your waist circumference tells how much body fat is located in your abdomen (your waist or stomach area). People who have more body fat around their abdomen may be at higher risk for diabetes, high blood pressure, and heart disease.

How to measure your waist circumference

Use a flexible (but not stretchy) measuring tape. Stand comfortably and breathe normally. Place the tape around your waist halfway between your lowest rib and the top of your pelvic bone (you can feel these bones with your fingers). The tape should be snug, but should not dent your skin. If your waist circumference is equal to or higher than the values below, the amount of fat located in your abdomen may increase your disease risk.

Waist circumfrence Affect on health risk
Women: 35 inches (88 cm) and greater Increased
Men: 40 inches (102 cm) and greater Increased

2. Body mass index (BMI)

Body Mass Index (BMI) is a tool that gives you a general idea of the level of health risk that may be linked with being overweight or underweight. There are 3 ways to find your BMI value: 1) calculate it yourself by dividing your weight (in kilograms) by your height (in metres) squared; 2) look it up on the chart under Step 1; or 3) use an online BMI calculator to figure it out (Helpful Resources section). Then, find the range in which your BMI value falls from Table 1 below to estimate the health risk linked to your body size. For more accurate results, BMI should always be used with waist circumference, as is done in the Canadian Guidelines for Body Weight Classification in Adults (see Table 2):

BMI value range Classification Risk for health problems
Less than 18.5 Underweight Increased health risk
18.5 to 24.9 Healthy weight Least health risk
25.0 to 29.9 Overweight Increased health risk
30.0 to 34.9 Obese Class I High health risk
35.0 to 39.9 Obese Class II Very high health risk
40.0 or higher Obese Class III Extremely high health risk
Source: http://www.hc-sc.gc.ca/fn-an/nutrition/weights-poids/guide-ld-adult/cg_quick_ref-ldc_rapide_ref-eng.php

Can you use BMI?

BMI should not be used to assess health risk for people who are:

  • 18 years old and younger
  • Pregnant or lactating

BMI may not accurately assess health risk for people who are:

  • Aged 65 and older
  • Very lean
  • Very muscular

Assessing your risk with the two measurements

Two measurements–BMI and waist circumference–can give you an idea of the extent to which your height, weight, and the amount of fat stored around your waist may be linked to health risks, including certain cancers, heart disease, diabetes, high blood pressure, and sleep apnea. Both of these measurements must be used together to get a correct idea of your health risk. Here's how to assess your own risk:

STEP 1:

Use this chart to see which weight category you fit in. See the example below.

Height

Healthy weight
BMI = 18.5 to 24.9
Overweight
BMI = 25.0 to 29.9
Obese
BMI over 30.0

5'0"

97 to 123 lbs 128 to 148 lbs over 148 lbs

5'2"

104 to 131 lbs 136 to 158 lbs over 158 lbs

5'4"

110 to 140 lbs 145 to 169 lbs over 169 lbs

5'6"

118 to 148 lbs 155 to 179 lbs over 179 lbs

5'8"

125 to 158 lbs 164 to 190 lbs over 190 lbs

5'10"

132 to 167 lbs 174 to 202 lbs over 202 lbs

*If your height falls in between these numbers, use the next highest value shown. For example, if you are 5’ 9” tall, use 5’ 10”.

Example

Susan weighs 138 lbs and is 5' 7" tall. First, find Susan's height in the first column-you will need to use 5'8". Now, look across that row to find Susan's weight (138 lbs). Susan's BMI value falls in the 125-158 lb range, which means that her BMI is between 18.5 and 24.9. This falls in the "healthy weight" category.

To get clear picture of Susan's overall risk, we need to measure her waist circumference - see below.

An image of a chart showing a height  and a healthy weight properly selected.

STEP 2:

Measure your waist circumference using the instructions above.

STEP 3:

Find your BMI classification and waist measurement on Table 2 below to see how these factors may influence your overall health risk.

Table 2: Health Risk Classification According to Body Mass Index and Waist Circumference 

Waist Circumfrence

BMI: Healthy weight BMI: Overweight BMI: Obese

Women: Less than 35 inches (88 cm)

Men: Less than 40 inches

Least risk Increased risk High risk

Women: 35 inches (88 cm) and greater

Men: 40 inches (102 cm) and greater

Increased risk High risk Very high risk
Source: http://www.hc-sc.gc.ca/fn-an/nutrition/weights-poids/guide-ld-adult/cg_quick_ref-ldc_rapide_ref-eng.php

Example

Susan's waist measures 36 1⁄2 inches. Her BMI value is classed as "healthy weight". By locating these two values on Table 2, we can see that Susan may be at increased health risk, based on her waist circumference and BMI value.

An image of the chart demonstrating how to select your breast cancer risk correctly.

While Susan's BMI alone is not linked to an increased health risk, her waist circumference shows that the amount of fat located around her waist may increase her risk of disease.

What does your risk level mean?

Health Canada recommends that we try to lower our overall health risk by reaching and keeping a healthy body weight. This means keeping your weight within the "healthy weight" range (based on BMI) and having a waist circumference of less than 88 cm (35 inches) for women and less than 102 cm (40 inches) for men. Together, healthy BMI and waist circumference are linked to the lowest health risk.