|ISSN No. 1606-7754 Vol.16 No.3 December 2008|
Hypoadiponectinemia in obese and diabetic subjects in the State of Qatar
N Rizk1, R Awni2, M Osman2 and M Zirie3
Department of Health Sciences, University of Qatar,1 Department of Clinical Chemistry,2 Department of Endocrinology,3 HMC, Doha, Qatar
Background: Obesity is commonly associated with insulin resistance (IR), and is a common cause of type 2 diabetes. Adiponectin is an adipose tissue protein that enhances insulin sensitivity and has anti-atherogenic properties. Objective: This study was done to determine the adiponectin level and its relations to key components of the metabolic syndrome in obese diabetic (OD), obese non-diabetic (OB) and control [non-obese, non-diabetic (NOND)] Qatari subjects. Research design and Methods: We examined 64 (OD), 61 (OB) and 72 (NOND) male and female subjects. After a 12 h overnight fasting, blood samples were withdrawn for determination of plasma glucose, insulin, adiponectin, HbA1C, uric acid, total cholesterol, triglycerides, HDL-C and LDL-C. Results: Plasma levels of adiponectin in OD (10.60 ± 3.64µg/mL) and OB (11.21 ± 3.41µg/mL) were significantly lower than NOND controls (14.73 ± 4.97µg/mL). Significant, inverse correlations were observed between adiponectin levels and BMI (r=-0.241, p<0.05), plasma glucose (r=-0.221, p<0.05), insulin (r=-0.280, p<0.05), C-peptide (r=-0.334, P<0.01), total cholesterol (r=-0.243, p<0.01,), triglycerides (r=-0.438, p<0.01), LDL-C (r=-0.214, p<0.05) and uric acid (r=-0.286, p<0.05). In addition, correlated positively with HDL-C(r=0.386, p<0.01). In multiple regression analysis, only TG was inversely associated with plasma level of adiponectin in all groups. Conclusion: This study provides the first evidence that adiponectin is reduced in Qatari obese subjects with and without diabetes. The measurement of circulating adiponectin among Qatari obese subjects is suggested to monitor cardiovascular disease (CVD) risks. Whether the plasma adiponectin level could be a suitable biomarker for following the clinical progress of CVD among Qatari obese and diabetic subjects warrants further investigation.
Keywords: Adiponectin, obesity, diabetes, metabolic syndrome, CVD, Qatar
Obesity is commonly associated with insulin resistance, hyperinsulinemia and is a major risk factor for the development of type 2 diabetes mellitus and cardiovascular diseases.1 The increased cardiovascular risk related to obesity has traditionally been ascribed to the presence of metabolic syndrome, which includes hypertension, insulin resistance, and dyslipidemia.2
Adiponectin is an adipose-specific plasma protein that has been shown to be an insulin-sensitizing hormone and has drawn substantial attention in research on metabolic syndrome.3,4 It suppresses hepatic glucose production, promotes lipid oxidation in muscle and may have a protective role against atherosclerosis.5
It has been showed that plasma adiponectin concentration is decreased in Caucasian, Pima Indians and Japanese subjects with obesity and type 2 diabetes.6-9 Thus, given that low circulating adiponectin concentration is now considered as a cardiovascular disease (CVD) risk factor,10 obese and type 2 diabetic subjects with low level of this peptide would have increased risk of developing atherosclerosis and coronary artery diseases (CAD).
The State of Qatar is a small country in the Arab Gulf area with a small population of approximately 820,000 inhabitants. The rapid transition in socioeconomic development after the discovery of oil has had a great impact on urbanization and life style of Qatar community. It results in an increase in the prevalence of obesity from 16.58% to 17.38% in males and from 27.92% to 29.31% in females from 2003 to 2005. Moreover, it is expected that the prevalence of obesity is going to increase to 18.7% and 31.6% among males and females of Qatari population in year 2010, respectively.11 In addition, the International Diabetes Federation (IDF) estimated that ≈33% of Qatari people aged between 20 and 79 years has diabetes and impaired glucose tolerance (IGT) in 2003 and it is expected that the rate will increase among the Qatari population to ≈39% in 2025.12
There are currently no equivalent data on adiponectin levels related to metabolic syndrome criteria and CVD risks available for the Qatari population. This is an important omission, given the increased focus on the prevalence of metabolic syndrome, diabetes and CVD in this region. Thus, we expect to determine the baseline level of adiponectin in this population. We therefore conducted a cross-sectional study to assess the plasma concentration of adiponectin and their correlation with various components of the metabolic syndrome among obese subjects with and without diabetes in State of Qatar.
Such study may be useful to unravel the complex interplay between adiponectin, and CVD risks among high risk obese and diabetic patients. The ultimate goal is to assist in early identification and management of patients with high propensity of developing coronary artery diseases.