Building Competency in Diabetes Education THE ESSENTIALS

5-8 | CHAPTER 5

Table 1. Canadian guidelines for body weight classification in adults using BMI

Classification

BMI category (kg/m 2 )* Risk of developing health problems

Underweight

<18.5

Increased

Normal weight 18.5–24.9

Least

Overweight

25.0–29.9

Increased

Obese

≥30.0 30.0–34.9 35.0–39.9 ≥40.0

Class i Class ii Class iii

High Very high Extremely high

* BMI values are age- and gender-independent and may not be correct for all ethnic populations. BMI = body mass index Reprinted from Health Canada, Canadian Guidelines for Body Weight Classification in Adults (12)

Waist circumference To determine WC, the measurer should stand beside the patient. WC is measured at the part of the torso located midway between the lowest rib and the iliac crest (top of the pelvic bone). The tape should fit without compressing any underlying soft tissues. Waist circumference is an indicator of health risk associated with excess abdominal fat. This measurement is useful in combination with BMI, since BMI does not account for distribution of body fat. Excessive upper body fat — or abdominal obesity — is a strong independent predictor of metabolic comorbidities (15,16). Cut-off values for WC vary among expert guidelines. Health Canada (12) and the National Cholesterol Education Program Adult Treatment Panel III guidelines (17,18) indicate th at WC values ≥102 cm (40 inches) in men and ≥88 cm (35 inches) in women are associated substantially with increased abdominal fat accumulation and health risks. However, the International Diabetes Federation has suggested population-specific WC cutoff values, given the evidence that, in other parts of the world, such as South Asia, lower WC values are associated with increased risk of complications, at WC lower than the existing Health Canada cut-off (19,20). Neither set of WC cutoff values has been validated against the development of clinical events. Further research is needed to assess population differences in susceptibility to deposition of visceral adipose tissue and to