Report

 

 

 

Appropriate Definition of Metabolic Syndrome among Iranian Adults: Report of the Iranian National Committee of Obesity

 

 

 

 

Fereidoun Azizi MD¹, Farzad Hadaegh MD², Davood Khalili MD^2,3, Alireza Esteghamati MD⁴,

Farhad Hosseinpanah MD⁵, Alireza Delavari MD⁶, Bagher Larijani MD⁶, Parvin Mirmiran PhD⁵,

Azadeh Zabetian MD², Yadollah Mehrabi PhD^2,7, Roya Kelishadi MD⁸, Hassan Aghajani MD^•9

 

 

 

Authors’ affiliations: ¹Endocrine Research Center, ²Prevention of Metabolic Disorders Research Center, Research Institute for Endocrine Sciences, Shahid Beheshti University of Medical Sciences, Tehran, Iran; ³School of Public Health, Shahid Beheshti University of Medical Sciences, Tehran; ⁴ Department of Endocrinology, Endocrinology and Metabolism Research Center, Vali-Asr Hospital, Tehran; ⁵Obesity Research Center, Research Institute for Endocrine Sciences, Shahid Beheshti University of Medical Sciences, Tehran; ⁶Endocrinology and Metabolism Research Center, Tehran University of Medical Sciences, Tehran; ⁷School of Public Health, Shahid Beheshti University of Medical Sciences, Tehran; ⁸Preventive Pediatric Cardiology Department, Isfahan Cardiovascular Research Center, Isfahan University of Medical Sciences, Isfahan; ⁹Center for Non-communicable Disease Control, Deputy of Health, Ministry of Health and Medical Education, Tehran, Iran.

 

•Corresponding author and reprints: Hassan Aghajani MD, Center for Non-communicable Disease Control, Deputy of Health, Ministry of Health and Medical Education, Tehran, Iran. Email: aghajanihas@yahoo.com

Accepted for publication: 11 August 2010

 

 

A complex accumulation of metabolic abnormalities including hyperinsulinism, impaired glucose tolerance, hypertension, low HDL cholesterol and hypertriglyceridemia were named syndrome X by Raven, two decades ago.¹ These non-communicable risk factors, which were later termed “metabolic syndrome” have an obscure etiology and a variety of clinical presentations. Therefore, the definition of metabolic syndrome has not been proposed on the basics of etiology and pathology, but has been defined with respect to phenotype. Various definitions of metabolic syndrome have been proclaimed by the World Health Organization,² Adult Treatment Panel (ATP) III,³ International Diabetes Federation (IDF),⁴ American Heart Association (AHA), and National Health Lung and Blood Institute (NHLBI).⁵ The AHA-NHLBI  proposal was a revised definition of ATP III with a reduction in fasting serum glucose from 110 to ≥100 mg/dL. Ethnic-specific values for waist circumference have been proposed for some populations, e.g. Europids and South-Americans.⁴ The IDF definition stated that instead of using a universal definition for central obesity, the ethnic-specific waist cut-off values should be considered when defining metabolic syndrome.

It has been reported that the prevalence of metabolic syndrome in the Islamic Republic of Iran is one of the highest worldwide. In the adult population of the Tehran Lipid and Glucose Study (TLGS), metabolic syndrome was found in 42% of women and 24% of men with a total age-standardized prevalence of 33.7%.⁶ The prevalence increased by age, from 10% in individuals 20 – 29 years of age to 60% in the 60 – 69 year age group. Moreover, the age-adjusted incidence of metabolic syndrome (defined by the ATP III definition) was found to be 20.4% (95%CI, 19.6 – 21.2) in the TLGS adults (18.4% male vs. 23.1% women) after three years of follow-up.⁷

The prevalence of metabolic syndrome has been reported to be 23% in Zanjan Province.⁸ A 2007 national survey of metabolic syndrome showed an age standardized prevalence of 34.7%, based on ATP III, 37.4% based on IDF and 41.6%, based on the ATP III/AHA/NHLBI definitions. The prevalence of metabolic syndrome was higher in women than men, and in urban residents compared to rural populations.⁹ Also, in the TLGS population the prevalence of metabolic syndrome (95%CI) was 32.1% (31.2 – 33.0) by the IDF definition and 18.4% (17.6 –19.2) according to the WHO definition; it would be of note that the IDF definition has shown good concordance with the ATP III definition and a low concordance with the WHO definition in this study.¹⁰

In September 2009, the Iranian Ministry of Health and Medical Education in collaboration with the Research Institute of Endocrine Sciences established the National Iranian Committee of Obesity which included endocrinologists, biostatisticians, cardiologists, pediatricians, epidemiologists, nutritionists and officials from the Iranian Center for Non-communicable Disease Control. The committee reviewed evidence-based studies on indices of central obesity in Iran. The cross-sectional studies reported waist circumference cut-off values with which to diagnose at least two other components of the cardiovascular disease (CVD) risk factors of IDF metabolic syndrome. The waist circumference cut-off values were 84 – 95 cm in women and 86 – 92 cm in men within various age groups¹¹ and 89 cm for men and 91 cm for women of all ages.⁹ The third national survey found a cut-off of 90 cm for waist circumference with which to diagnose metabolic syndrome in both genders.¹² The only prospective outcome-based cohort study in Iran found an identical waist circumference cut-off value of 94.5 cm for both men and women that could predict the incidence of CVD.¹³ Based on the above-mentioned evidence, the Iranian National Committee of Obesity announced equal waist circumference cut-offs of ≥90 cm in both genders at risk for CVD risk factors, and that of ≥95 cm in both genders to be at high risk CVD events requiring immediate preventive measures.¹⁴

A recent joint scientific statement of IDF, NHLBI, AHA, World Heart Federation, International Atherosclerosis Society and the International Association for the Study of Obesity harmonized the definition of metabolic syndrome. It suggested that none of components are obligatory for metabolic syndrome, however three out of five components would qualify a person for metabolic syndrome. It confirmed that waist circumference would continue to be a useful preliminary screening tool and should have national or regional cut-off points. For the remaining four components, a single set of cut-off points previously defined by all associations was suggested.¹⁵

The Iranian National Committee of Obesity considered the identical cut point of waist circumference for both genders in Iran¹⁴ as well as the abovementioned new harmonizing definition of metabolic syndrome,¹⁵ and proposed a unified clinical and epidemiological study of metabolic syndrome among Iranians (Table 1).

In conclusion, there is rapid growth of the prevalence of obesity¹⁶ and metabolic syndrome¹⁷ in Iran; thus, having a uniform and harmonized definition for waist circumference and metabolic syndrome should make clinical and epidemiological investigations comparable and more appropriate for trend studies.

 

 

References

1.     Reaven GM. Banting lecture 1988. Role of insulin resistance in human disease. Diabetes. 1988; 37: 1595 – 607.

2.     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 – 553.

3.     National Cholesterol Education Program (NCEP) Expert Panel on Detection, Evaluation, and Treatment of High Blood Cholesterol in Adults (Adult Treatment Panel III). 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) final report. Circulation. 2002; 106: 3143 – 3421.

4.     Alberti KG, Zimmet P, Shaw J, IDF Epidemiology Task Force Consensus Group. The metabolic syndrome--a new worldwide definition. Lancet. 2005; 366: 1059 – 1062.

5.     Grundy SM, Cleeman JI, Daniels SR, Donato KA, Eckel RH, Franklin BA, et al. American Heart Association; National Heart, Lung, and Blood Institute. Diagnosis and management of the metabolic syndrome: An American Heart Association/National Heart, Lung, and Blood Institute Scientific Statement. Circulation. 2005; 112: 2735 – 2752.

6.     Azizi F, Salehi P, Etemadi A, Zahedi-Asl S. Prevalence of metabolic syndrome in an urban population: Tehran Lipid and Glucose Study. Diabetes Res Clin Pract. 2003; 61: 29 – 37.

7.     Zabetian A, Hadaegh F, Sarbakhsh P, Azizi F. Weight change and incident metabolic syndrome in Iranian men and women: A 3-year follow-up study. BMC Public Health. 2009; 9: 138.

8.     Sharifi F, Mousavinasab SN, Saeini M, Dinmohammadi M. Prevalence of metabolic syndrome in an adult urban population of the west of Iran. Exp Diabetes Res. 2009; 136501. Epub 2009 Nov 4.

9.     Delavari A, Forouzanfar MH, Alikhani S, Sharifian A, Kelishadi R. First nationwide study of the prevalence of the metabolic syndrome and optimal cutoff points of waist circumference in the Middle East: The National Survey of Risk Factors for Noncommunicable Diseases of Iran. Diabetes Care. 2009; 32: 1092 – 1097.

10.  Zabetian A, Hadaegh F, Azizi F. Prevalence of metabolic syndrome in Iranian adult population, concordance between the IDF with the ATPIII and the WHO definitions. Diabetes Res Clin Pract. 2007; 77: 251 – 257.

11.  Mirmiran P, Esmaillzadeh A, Azizi F. Detection of cardiovascular risk factors by anthropometric measures in Tehranian adults: Receiver operating characteristic (ROC) curve analysis. Eur J Clin Nutr. 2004; 58: 1110 – 1118.

12.  Esteghamati A, Abbasi M, Rashidi A, Meysamie A, Khalilzadeh O, Haghazali M, et al. Optimal waist circumference cut-offs for the diagnosis of metabolic syndrome in Iranian adults: Results of the Third National Survey of Risk Factors of Non-communicable Diseases (SuRFNCD-2007). Diabet Med. 2009; 26: 745 – 746.

13.  Hadaegh F, Zabetian A, Sarbakhsh P, Khalili D, James WP, Azizi F. Appropriate cutoff values of anthropometric variables to predict cardiovascular outcomes: 7.6-year follow-up in an Iranian population. Int J Obes (Lond). 2009; 33: 1437 – 1445.

14.  Azizi F, Khalili D, Aghajani H, Esteghamati A, Hosseinpanah F, Delavari A, et al. Appropriate waist circumference cut-off points among Iranian adults: The first report of the Iranian National Committee of Obesity. Arch Iran Med. 2010; 13: 243 – 244.

15.  Alberti KG, Eckel RH, Grundy SM, Zimmet PZ, Cleeman JI, Donato KA, et al. International Diabetes Federation Task Force on Epidemiology and Prevention; National Heart, Lung, and Blood Institute; American Heart Association; World Heart Federation; International Atherosclerosis Society; International Association for the Study of Obesity. Harmonizing the metabolic syndrome: a joint interim statement of the International Diabetes Federation Task Force on Epidemiology and Prevention; National Heart, Lung, and Blood Institute; American Heart Association; World Heart Federation; International Atherosclerosis Society; and International Association for the Study of Obesity. Circulation. 2009; 120: 1640 – 1645.

16.  Esteghamati A, Khalilzadeh O, Mohammad K, Meysamie A, Rashidi A, Kamgar M, et al. Secular trends of obesity in Iran between 1999 and 2007: National surveys of risk factors of non-communicable diseases. Metab Syndr Relat Disord. 2010; 8: 209 – 213.

17.  Moayeri H, Rabbani A, Keihanidoust ZT, Bidad K, Anari S. Overweight adolescents: A group at risk for metabolic syndrome (Tehran adolescent obesity study). Arch Iran Med. 2008; 11: 10 – 15.