Procedures for the measurement of the waist circumference
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- Background
- Standardized instructions for the measurement of waist circumference
- Critical values of waist circumference
The concept of the Metabolic Syndrome
Procedures for the measurement of the waist circumference
Background
It is now well accepted that obesity represents a heterogeneous condition from a metabolic standpoint. A preferential deposition of adipose tissue in the abdominal cavity has been associated with a cluster of atherogenic and diabetogenic metabolic complications characterizing the Metabolic Syndrome. For instance, many studies have reported that excess visceral adipose tissue accumulation is associated with elevated plasma triglyceride concentrations, marked reductions in plasma HDL-cholesterol levels and an increased proportion of small, dense LDL particles, despite normal LDLcholesterol. Furthermore, there is also solid evidence to suggest that among obese patients, the most severe disturbances in indices of plasma glucose-insulin homeostasis resulting from an insulin resistant state are observed in patients with a high accumulation of visceral adipose tissue. Finally, abdominal obesity has been associated with hypertension and with a pro-inflammatory and thrombotic state. It is important to keep in mind that presumably normal weight individuals may nevertheless be characterized by an excess of visceral adipose tissue and therefore at increased risk of metabolic complications. Thus, under those circumstances, such normal weight subjects characterized by an excess of visceral adipose tissue may also show the features of the Metabolic Syndrome.
The precise measurement of visceral adipose tissue requires sophisticated and precise techniques, is very expensive and not accessible to most health professionals. However, anthropometric measurements have been proposed to estimate the amount of abdominal adipose tissue. For instance, it has been reported that the waist circumference alone was generally closely associated with the levels of visceral adipose tissue. Moreover, since the correlation between height and waist girth has been shown to be weak or even nonsignificant, it appears that there is no need to adjust waist circumference for height in the estimation of the absolute amount of visceral adipose tissue. Thus, on the basis of the strong relationship between visceral obesity and waist circumference, the latter seems to be a key element to identify individuals likely to have the features of the Metabolic Syndrome.
Therefore, the waist circumference measurement may be useful for clinicians not only in the estimation of risk but also as a therapeutic target as it could allow to monitor changes in visceral adipose tissue over time. These changes could occur even in absence of any variation in weight or in total body fatness.
Standardized instructions for the measurement of waist circumference
Note:
- It is preferable to use a tape with a spring handle in order to control the tension applied on the abdomen (e.g. Gulick model).
- Otherwise, use an unstretchable tape (avoid fabric tape) with an ungraduated extremity of 3-5 cm in order to properly grab the tape.
The subject stands with his feet shoulder-width apart. The arms hang on each side of the body but out at an angle of about 30o to allow the person taking the measurement to work comfortably. If this is not comfortable, alternatively participants can cross their arms on their shoulders in a relaxed manner. A slight tension should be applied to the tape (until the red mark appears) at the moment of the reading.
The measurement is taken at the end of a normal expiration, while ensuring that the participant does not contract the abdominal muscles. (Experimenter can engage conversation with patient if he is suspected to contract the abdominal muscles). The measurement is made twice and a third time if the difference between the first two measurements is greater than 5% (+/- 1 cm). The two closest measurements will be averaged.
 Arms at 30 degres |
 Arms crossed |
Detailed instructions
- Mark with a pencil bony landmarks of the right and left last rib margin.
- Mark with a pencil bony landmarks of the right and left iliac crest.
- Mark with a pencil the mid-distance between the last rib margin and the top of the iliac crest of the two sides.
4. Place the tape horizontally directly on the skin with respect to both mid-distance landmarks. Note: A mirror could be used to facilitate this procedure.
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5. A slight tension should be applied to the tape (until the red mark appears if you use a tape with a spring handle) at the moment of the reading
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Tips
If the measurement is performed in a physician’s office, it is important to untie your belt and your pant/skirt in order to remove any pressure in the abdomen. It is recommended to completely remove the blouse/shirt. However, women could only pull up the top garment and tuck it under the bra.
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Critical values of waist circumference
While very useful in clinical practice for the time being, criteria and cut-off values to identify high-risk individuals with the Metabolic Syndrome remain to be validated and are likely to differ in various populations (men vs. women, different age groups and ethnic populations, etc).
The concept of the Metabolic Syndrome
The concept of the Metabolic syndrome viewed as precursor to the development of both type 2 diabetes and cardiovascular disease has progressively emerged with a formal recognition by the World Health Organization (WHO) in 1998 and the National Cholesterol Education Program Adult Treatment Panel III in 2001 (NCEP ATP III), 1,2 which have recently proposed a formal definition of the Metabolic Syndrome.
The respective criteria proposed to define the Metabolic Syndrome are listed in Table I. Both definitions include type 2 diabetes and impaired fasting glycaemia, as well as hypertriglyceridaemia and a low HDL-cholesterol concentration as component traits.
The WHO definition included also the presence of impaired glucose tolerance determined with a glucose load test. There are also a few differences between these two definitions. The WHO criteria consider both central obesity (defined by the waist-to-hip ratio) and overall obesity (defined by the BMI) while the NCEP criteria consider only central obesity (defined by the waist circumference).
Furthermore, blood pressure thresholds differ between the two criteria with a higher value in the WHO definition. In addition, elevated microalbuminuria is a component trait in the WHO definition while it is not considered for NCEP ATP III. These differences in the definition and proposed criteria for the definition of the Metabolic Syndrome show that some uncertainty persists in this area.
| Table I. Definitions of the metabolic syndrome according to World Health Organisation (WHO) and National Cholesterol Education Program Adult Treatment Panel III (NCEP ATP III) criteria. | |
|---|---|
| Risk factors | Defining level |
| NCEP ATP III definition: 3 or more of the following criteria | |
| Abdominal obesity | >102 cm, Men |
| Waist circumference | >88 cm, Women |
| Triglycerides | >=150 mg/dL |
| HDL-cholesterol | < 40 mg/dL, Men < 50 mg/dL, Women |
| Blood pressure | >=130/85 mm Hg |
| Fasting glucose | >=110 mg/dL |
| WHO definition Impaired fasting glucose or impaired glucose tolerance or diabetes plus 2 or more of: | |
| Waist-to-hip ratio | > 0.85 (women) or > 0.9 (men) and/or BMI >30 kg/m2 |
| Triglycerides | >=150 mg/dL and/or HDL-cholesterol < 40 mg/dL |
| Blood pressure | >=140/90 mm Hg |
| Microalbuminuria | urinary albumin excretion rate >=20 µg/min or albumin/creatinine ratio >= 30 µg/min |
References
- Alberti KG, Zimmet PZ. Definition, diagnosis and classification of diabetes mellitus and its complications. Part 1: Diagnosis and classification of diabetes mellitus provisional report of a WHO consultation. Diabet Med 1998; 15: 539-53.
- Expert Panel on Detection, Evaluation, and Treatment of High Blood Cholesterol in Adults. Executive Summary of the Third Report of the National Cholesterol Education Program (NCEP) Expert Panel on Detection, Evaluation, and Treatment of High Blood Cholesterol in Adults (Adult Treatment Panel III). JAMA 2001; 285: 2486-97.
