Reviews/Commentaries/ADA Statements CONSENSUS STATEMENT Waist Circumference and Cardiometabolic Risk A Consensus Statement from Shaping America’s Health: Association for Weight Management and Obesity Prevention; NAASO, The Obesity Society; the American Society for Nutrition; and the American Diabetes Association 1 5 SAMUEL KLEIN, MD RUDOLPH L. LEIBEL, MD tant risk factor for obesity-related dis- 2 6 DAVID B. ALLISON, PHD CATHY NONAS, MS, RD, CDE eases. Excess abdominal fat (also known 3 7 STEVEN B. HEYMSFIELD, MD RICHARD KAHN, PHD 4 as central or upper-body fat) is associated DAVID E. KELLEY, MD with an increased risk of cardiometabolic disease. However, precise measurement of abdominal fat content requires the use besity is an important risk factor for plications and mortality rate (e.g., 3,4). of expensive radiological imaging tech- cardiometabolic diseases, including Men and women who have a BMI Ն30 niques. Therefore, waist circumference O diabetes, hypertension, dyslipide- kg/m2 are considered obese and are gen- (WC) is often used as a surrogate marker mia, and coronary heart disease (CHD). erally at higher risk for adverse health of abdominal fat mass, because WC cor- Several leading national and international events than are those who are considered relates with abdominal fat mass (subcuta- institutions, including the World Health overweight (BMI between 25.0 and 29.9 neous and intra-abdominal) (5) and is Organization (WHO) and the National kg/m2) or lean (BMI between 18.5 and associated with cardiometabolic disease Institutes of Health, have provided guide- 24.9 kg/m2). Therefore, BMI has become risk (6). Men and women who have waist lines for classifying weight status based on the “gold standard” for identifying pa- circumferences greater than 40 inches BMI (1,2). Data from epidemiological tients at increased risk for adiposity- (102 cm) and 35 inches (88 cm), respec- studies demonstrate a direct correlation related adverse health outcomes. tively, are considered to be at increased between BMI and the risk of medical com- Body fat distribution is also an impor- risk for cardiometabolic disease (7). These cut points were derived from a re- gression curve that identified the waist ●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●● circumference values associated with a BMI Ն30 kg/m2 in primarily Caucasian From the 1Division of Geriatrics and Nutritional Science, Center for Human Nutrition, Washington Uni- versity School of Medicine, St. Louis, Missouri; the 2Clinical Nutrition Research Unit, University of Alabama men and women living in north Glasgow at Birmingham, Birmingham, Alabama; the 3Clinical Research Department, Metabolism, Merck Pharmaceu- (8). tical Company, Rahway, New Jersey; the 4Obesity and Nutrition Research Center, University of Pittsburgh, 5 An expert panel, organized by the Na- Pittsburgh, Pennsylvania; the Naomi Berrie Diabetes Center, Columbia University, New York, New York; tional Heart, Lung and Blood Institute, the 6Obesity and Diabetes Programs, North General Hospital, New York, New York; and the 7American Diabetes Association, Alexandria, Virginia. has recommended that WC be measured Address correspondence and reprint requests to Samuel Klein, MD, Washington University School of as part of the initial assessment and be Medicine, 660 South Euclid Ave., Campus Box 8031, St. Louis, MO 63110. E-mail: [email protected]. used to monitor the efficacy of weight loss Approved for publication 7 March 2007. therapy in overweight and obese patients D.B.A. has received research grants from Frito-Lay and OMP; has served as a consultant to Kraft Foods, Ͻ 2 Pfizer, Bristol-Myers Squibb, and Bio Era; and has received financial support from Lilly, Pfizer, Merck who have a BMI 35 kg/m (7). How- Pharmaceutical Company, Unilever, Coca-Cola, General Mills, International Life Sciences Institute, Glaxo- ever, measurement of WC has not been SmithKline, OMP, Jansen Pharmaceuticals, and Frito-Lay. S.K. has received research grants from Sanofi- widely adopted in clinical practice, and Aventis, Merck, and Takeda for clinical trials; has served as a consultant to Sanofi-Aventis, Amylin the anatomical, metabolic, and clinical Pharmaceuticals, EnteroMedics, Dannon-Yakult, and Merck Pharmaceutical Company. S.B.H. is an em- ployee of Merck Pharmaceutical Company. D.E.K. has received research grants from Novartis Pharmaceu- implications of WC data can be confus- ticals, Sanofi-Aventis, and Pfizer; has served as a consultant/advisor to Novartis Pharmaceuticals, Sanofi- ing. Therefore, Shaping America’s Health: Aventis, Pfizer, Merck Pharmaceutical Company, and GlaxoSmithKline; and has been on speaker’s bureaus Association for Weight Management and for Novartis Pharmaceuticals, Sanofi-Aventis, and Merck Pharmaceutical Company. R.L.L. has received Obesity Prevention; NAASO: The Obesity research grants from GlaxoSmithKline and has been a consultant/advisor to Amylin Pharmaceuticals, Merck Pharmaceutical Company, Arisaph Pharmaceuticals, and Genaera Corporation. C.N. has been a consultant/ Society; and the American Diabetes Asso- advisor to Amylin Pharmaceuticals, GlaxoSmithKline, and Slim Fast. ciation convened a panel, comprised of Abbreviations: CHD, coronary heart disease; CT, computed tomography; IAAT, intra-abdominal adi- members with expertise in obesity man- pose tissue; MRI, magnetic resonance imaging; NHANES III, National Health and Nutrition Examination agement, obesity-related epidemiology, Survey III; SAAT, subcutaneous abdominal adipose tissue; WC, waist circumference; WHO, World Health Organization. adipose tissue metabolic pathophysiol- A table elsewhere in this issue shows conventional and Syste`me International (SI) units and conversion ogy, statistics, and nutrition science to re- factors for many substances. view the published scientific literature DOI: 10.2337/dc07-9921 and hear presentations from other experts © 2007 by NAASO and the American Diabetes Association. The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore be hereby in these fields. The Consensus Panel met marked “advertisement” in accordance with 18 U.S.C. Section 1734 solely to indicate this fact. from December 17 to 20, 2006, in Wash- DIABETES CARE, VOLUME 30, NUMBER 6, JUNE 2007 1647 Consensus Statement ington, DC, and was charged to provide Table 1—Distribution of adipose tissue mass commonly used to describe intra- answers to the following four questions: in lean and obese men abdominal fat and includes both intra- 1. What does waist circumference peritoneal fat (mesenteric and omental measure? Lean Obese fat), which drains directly into the portal 2. What are the biological mecha- men men circulation, and retroperitoneal fat, which nisms responsible for the associa- drains into the systemic circulation. tion between waist circumference BMI (kg/m2) 23 37 Magnetic resonance imaging (MRI) and cardiometabolic risk? Body weight (kg) 71 116 and computed tomography (CT) are con- 3. What is the power of waist cir- Body fat (%) 15 32 sidered the gold-standard methods for cumference to predict adverse car- Total body fat (kg) 10 37 determining the quantity of subcutaneous diometabolic outcomes? How Total subcutaneous fat (kg) 9 32 abdominal adipose tissue (SAAT) and in- does the predictive power of waist Abdominal fat (kg) 4.3 12.3 tra-abdominal adipose tissue (IAAT) (17). circumference compare with that Subcutaneous (kg) 2.4 7.2 Most MRI and CT methods involve acqui- of BMI? Does measuring waist cir- Intra-abdominal (kg) 1.9 5.1 sition of cross-sectional abdominal im- cumference in addition to BMI im- Intraperitoneal (kg) 1.1 3.5 ages, which are then analyzed for fat prove predictability? Retroperitoneal (kg) 0.8 1.6 content. A single slice is often acquired at 4. Should waist circumference be Adapted from reference 16. the L4-L5 intervertebral level to estimate measured in clinical practice? SAAT and IAAT volume, expressed as 3 cm . However, L4-L5 imaging does not surements are typically taken three times provide the best estimate of total IAAT QUESTION 1: What does waist and recorded to the nearest 0.1 cm. Al- mass, which is more reliably estimated circumference measure? though specific techniques have been rec- several centimeters cephalad of the L4-L5 Measurement technique. Waist cir- ommended for measuring WC in the intervertebral space (17,18). In addition, cumference is actually a perimeter, which clinical setting (2,10), there is no uni- measurement site influences the relation- provides an estimate of body girth at the formly accepted approach. Training tech- ship between IAAT volume and cardio- level of the abdomen. Different anatomi- nicians and even patients to use an metabolic risk; the association between cal landmarks have been used to deter- appropriate technique for measuring WC IAAT volume and presence of the meta- mine the exact location for measuring WC is essential to obtain reliable data; special bolic syndrome is greater when IAAT vol- in different clinical studies, including: 1) tape measures, instructional manuals, ume is determined at the L1-L2 than at the midpoint between the lowest rib and the and videotapes are available for this pur- L4-L5 level (19). Currently, there is no iliac crest; 2) the umbilicus; 3) narrowest pose (11). universally accepted site for measuring (minimum) or widest (maximum) waist The reproducibility of WC measure- IAAT and SAAT. circumference; 4) just below the lowest ments at all sites is high for both men and The relationship between WC, rib; and 5) just above the iliac crest. The women (e.g., iliac crest site, intra-class weight, and BMI can be conceptualized specific site used to measure WC influ- correlation coefficient, r ϭ 0.998 and r ϭ by using simple geometric relationships ences the absolute WC value that is ob- 0.999, respectively) (9,12,13). The corre- that consider the body as a cylinder; WC tained (9). The most commonly used sites lation between technician- and self- is the cylinder’s circumference, height is reported in studies that evaluated the re- measured WC after proper training can its length, and weight is a measure of lationship between morbidity or mortal- also be high for both men (r ϭ 0.95) and mass.