"High Waist Circumference Independently Associated With Cardiovascular Disease and Especially Diabetes"
LONDON, U.K. -- October 23, 2007 -- Findings from the International Day for the Evaluation of Abdominal Obesity (IDEA) study published in today's issue of Circulation, the journal of the American Heart Association, confirm that a high waist circumference (WC) is strongly associated with cardiovascular disease (CVD) and diabetes independently of body mass index (BMI) and age.
The first of its kind, IDEA was a large international study assessing the frequency of abdominal obesity in nearly 170,000 people and involving over 6,300 primary care offices in 63 countries. The study demonstrates that abdominal adiposity, as measured by WC is highly correlated with an increased risk for cardiovascular disease and diabetes worldwide.1
The IDEA study results show that WC and BMI are independently associated with both CVD and diabetes, regardless of age, sex and geography.1
"The IDEA study confirms to us the importance of measuring waist circumference in primary care, alongside current measures such as BMI, blood pressure, blood glucose and lipid levels, in order to identify patients who are at increased cardiovascular and diabetes risk," said Beverley Balkau, PhD, Epidemiologist, INSERM U780, France and member of the IDEA Study Executive Committee.
The study not only measured frequency of abdominal obesity but also determined the relationship between WC, BMI and the frequency of CVD and diabetes. The results demonstrated that in both men and women, WC and BMI were both independently associated with CVD and diabetes. There was a stronger relationship for WC than for BMI across regions, for both men and women.1 The relationship between WC, CVD and particularly diabetes was seen even in lean patients (BMI 25 kg/m[2).
"The IDEA study provides clear evidence that waist circumference is a clinical marker for such risk, even in patients with normal weight. The study clearly shows that if you show primary care physicians how to properly measure waist circumference, such measurement predicts risk of diabetes and cardiovascular disease at any BMI level.
This study clearly confirms that waist girth is a vital sign which must be recorded in the medical record of all patients," said Jean-Pierre Després, PhD, Director of Research, Cardiology, Hôpital Laval, Université Laval, Québec City, Québec, Canada and member of the IDEA Study Executive Committee.
The worldwide frequency of known CVD in men in the primary care population in the IDEA study was 16% and ranged between 10% in Latin America to 26% in Eastern Europe.1 The worldwide frequency of known CVD in women was 12.5% and ranged between seven% in North America to 23% in Eastern Europe.1
The IDEA study results confirm and support the findings of the INTERHEART study, but add greatly to this knowledge because of the size and geographic spread of the IDEA study population. The patient participation rate in the survey was high, with 97% of patients agreeing to have their WC measured by their primary care physician, suggesting that this could be easily measured and included in clinical practice worldwide.1
The findings of IDEA, associating waist circumference with diabetes and with all stages of CVD, extend those from the INTERHEART study," said Dr Steve Haffner, Epidemiologist, University of Texas Health Sciences Center, USA and member of the IDEA Study Executive Committee. "It is likely that early intervention to target adiposity would have the greatest impact on lifetime manifestations of diabetes and CVD."
BMI, an established risk factor for CVD, does not take into account the wide variation in body fat distribution across different individuals and populations. Measurements that are more sensitive to individual differences in abdominal obesity might be useful for identifying CVD. Waist circumference is a convenient measure of abdominal obesity that is unrelated to height and correlates closely with BMI and total body fat.3
Abdominal obesity can be simply measured by WC and is an indicator of intra-abdominal adiposity, the hidden fat present deep within the abdomen associated with the development of metabolic disorders. Intra-abdominal adiposity has been identified as an underlying cause of cardiometabolic risk factors, such as elevated triglycerides, low HDL-cholesterol and high blood sugar.
While adipose tissue is useful for storage and release of energy, it produces active substances known as hormones. Too much of this "high risk" fat is responsible for abnormal levels of these substances, interfering with normal metabolic function and leading to high blood sugar and unhealthy cholesterol levels, which can increase the risk for heart disease and diabetes.
CVD is the leading cause of death and has emerged as a prominent public health issue around the world. One in 8 men and one in 17 women die from CVD before the age of 65 in European countries. Obesity is typically measured by BMI; however, recent findings have shown that abdominal obesity is a much better determinant of CVD risk than weight or BMI.2
Diabetes currently affects more than 194 million adults worldwide and is expected to affect 333 million by 2025. Each year, a further 7 million people develop diabetes and over 3 million deaths are directly tied to diabetes.9 Every 10 seconds a person dies from diabetes-related causes, which is equivalent to six deaths every minute.9 Worldwide, around 58% of type 2 diabetes cases are attributable to excess body fat and this figure is predicted to double by 2030.9 Because of the rising prevalence of diabetes worldwide, it now ranks alongside smoking, high blood pressure and cholesterol disorders as a major risk factor for cardiovascular disease.9 Patients with diabetes have a more than two-fold increased risk of cardiovascular mortality than non-diabetic patients.
IDEA survey objectives and design
The IDEA study was an international non-interventional epidemiological cross-sectional study conducted in 63 countries across five continents. The study aimed to estimate the frequency of abdominal obesity, as measured by WC, in an unselected population of consecutive patients consulting a randomly selected sample of primary care physicians on two pre-specified half-days. The study also estimated the association between abdominal obesity, CVD and diabetes.
The study utilised a complex methodology, taking a random sample of primary care physicians; representing all geographic areas within each participating country. This ensured that a good representation of patient data was collected. All patients aged between 18 and 80 years consulting their primary care physician on the two pre-specified half-days were asked for informed consent and invited to participate, irrespective of their reason for consultation. All screened patients not known to be pregnant were eligible for inclusion in the study.
The variables assessed and recorded were WC (measured in centimetres or inches), height (cm/in) and body weight (kg/lbs). In addition, demographic data were collected on gender, age and highest level of education. The presence or absence of known CVD risk factors such as smoking status, diabetes (either type 1 or type 2 diabetes) and existing CVD (coronary heart disease, stroke or prior revascularisation) were also recorded.
Of 182,970 patients screened, 177,345 patients agreed to participate, a response rate of 97%. Data were analysed in 168,159 patients (69,409 men; 98,750 women) meeting the inclusion criteria and for whom full data records were obtained.
The IDEA survey is the first part of a large epidemiological programme and two other studies: the International Study of Prediction of Intra-Abdominal Adiposity and its Relationship with Cardiometabolic Risk/Intra-Abdominal Adiposity (INSPIRE ME) and the INSPIRE ME Intra-Abdominal Adiposity (INSPIRE ME IAA) study have now been initiated. INSPIRE ME will provide further epidemiological evidence of the relationship between cardiometabolic risk markers and previous CVD events and type 2 diabetes. INSPIRE ME IAA will capture the new occurrence of cardiovascular events or type 2 diabetes to provide further evidence on the link between intra-abdominal adiposity (measured by CT-scan), WC and these cardiovascular and metabolic diseases. The study will have a prospective design with a follow-up of three years.
The IDEA survey was sponsored by an unrestricted grant from sanofi-aventis.
REFERENCES:
1. Haffner S on behalf of the IDEA Executive Committee. Waist circumference and Body Mass Index are both independently associated with cardiovascular disease. The International Day for the Evaluation of Abdominal Obesity (IDEA) survey. Circulation 2007; 116;1942-1951.
2. Yusuf S, Hawken S, Ôunpuu S, Dans T, Avezum A, Lanas F et al., Effect of potentially modifiable risk factors associated with myocardial infarction in 52 countries (the INTERHEART study): Case control study. The Lancet. 2004; 364: 937-952.
3. Zhu S, Wang Z, Heshka S, Heo M, Faith MS, Heymsfield SB. Waist circumference and obesity-associated risk factors among whites in the third National Health and Nutrition Examination Survey: clinical action thresholds. Am J Clin Nutr. 2002; 76:743-9.
4. Despres JP Lemieux I, Prud'homme D. Treatment of obesity: need to focus on high risk abdominally obese patients. BMJ. 2001; 322;716-720.
5. Lakka H-M, Lakka TA, Tuomilehto J, Salonen JT. Abdominal obesity is associated with increased risk of acute coronary events in men. Eur Heart J. 2002; 23:706-713.
6. Kershaw EE, Flier JS. Adipose Tissue as an Endocrine Organ. J Clin Endocrinol Metab. 2004. 89:2548-2556.
7. Myths and facts. [fact sheet on the Internet]. World Heart Federation. Geneva c2004 [cited 7th February 2006]. Available from: http://www.worldheart.org/call-to-action-myths-facts.php.
8. Rayner M & Petersen S. European Cardiovascular Disease Statistics. British Heart Foundation Health Promotion Research Group. Volume 4 2004.
9. International Diabetes Federation. [Factsheet on the Internet]. Diabetes e-Atlas C2001. Brussels c 2003. [Last accessed 23 November 2006]. Available at: http://www.eatlas.idf.org/webdata/docs/Atlas%202003-Summary.pdf.
10. Haffner SM, Lehto S, Rönnemaa T, Pyörälä K, Laakso M. Mortality from coronary heart disease in subjects with type 2 diabetes and in nondiabetic subjects with and without prior myocardial infarction. Engl J Med. 1998; 339:229-234.
SOURCE: IDEA Steering Committee
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