Sultan Qaboos University Med J, August 2014, Vol. 14, Iss. 3, pp. e393-396, Epub. 24TH Jul 14 Submitted 28TH Sep 13 Revision Req. 12TH Nov 13; Revision Recd. 8TH Mar 14 Accepted 20TH Mar 14 1Department of Surgery, Sultan Qaboos University Hospital; 2Department of Medicine, College of Medicine & Health Sciences, Sultan Qaboos University, Muscat, Oman *Corresponding Author e-mail: humaid44@gmail.com مقاومة االنسولني وارتباطها مع بعوامل االختطار لتطور مرض السكري يف 100 من طالب الطب العمانيني حميد حمود الفرعي، عي�سى العبودي، عزاء ال�سوافية، نورة البو�سعيدية، نيكول�س ودهاو�س abstract: Objectives: The aim of this study was to assess the prevalence of insulin resistance (IR) in healthy young Omanis and relate this with their body mass index (BMI) and family history (FH) of diabetes mellitus (DM). Methods: This study was conducted between May 2009 and February 2010 at Sultan Qaboos University, Muscat, Oman. A detailed questionnaire was completed by 50 male and 50 female medical students between 20–25 years old. Fasting blood samples were obtained for serum glucose and insulin measurements. IR was calculated using the homeostasis model assessment-estimated insulin resistance (HOMA-IR) formula (fasting insulin x fasting glucose/22.5) and a value above 2.5 was considered elevated. The results were analysed using the Statistical Package for the Social Sciences (SPSS). Results: Participants were classified into the following BMI categories: 59% were normal (18.5–24.9 kg/m2), 26% were overweight or obese (>24.9 kg/m2) and 15% were underweight (<18.5 kg/m2). A FH of DM was present in 74%. The HOMA-IR index was elevated in 16% and was directly correlated to the BMI (P = 0.003). There was no correlation between IR and a positive FH of DM. Conclusion: There is a high prevalence of IR (16%) and obesity (26%) in healthy young Omani medical students. Counselling is recommended for all overweight and obese individuals in an attempt to prevent or delay the onset of DM in the future. Keywords: Insulin Resistance; Diabetes; Body Mass Index; Obesity; Young Adults; Oman. مع ذلك عالقة و الأ�سحاء العمانيني ال�سباب عند )IR( الأن�سولني مقاومة انت�سار مدى تقييم هو الدرا�سة هذه من الهدف الهدف: امللخ�ص: وفرباير 2009 مايو بني الدرا�سة هذه اأجريت الطريقة: .)DM( ال�سكري داء بخ�سو�س لديهم العائلي والتاريخ )BMI( اجل�سم كتلة موؤ�رس الطب طالب من الإناث من 50 و الذكور من 50 قبل من مف�سل ا�ستبيان تعبئة مت عمان. �سلطنة م�سقط، يف قابو�س ال�سلطان جامعة يف 2010 با�ستخدام الأن�سولني مقاومة ح�ساب مت ال�سيام. حالة يف الأن�سولني و اجللوكوز لقيا�س الدم من عينات اأخذ مت �سنة. 25-20 اأعمارهم ترتاوح وقد لالأن�سولني. مقاوم اعتباره فيتم 2.5 من اأعلى القراءة كانت فاإذا الأن�سولني/22.5( X اجللوكوز ( ب�سيغة )HOMA - IR( معادلة 59% كالتايل: )BMI( اجل�سم كتلة معامل ح�سب لفئات امل�ساركني ت�سنيف مت النتائج: .)SPSS( برنامج با�ستخدام النتائج حتليل مت الوزن نق�س من يعانون 15% و كجم/م2( 24.9 >( ال�سمنة اأو الوزن زيادة من يعانون 26% و كجم/م2(، 24.9-18.5( طبيعية كانت )< 18.5 كجم/م2(. وكانت ن�سبة وجود التاريخ العائلي ملر�س ال�سكري عند الأ�سخا�س امل�ساركني يف الدرا�سة %74. وكانت ن�سبة مقاومة الأن�سولني %16 وكان له ارتباط مبا�رس مع موؤ�رس كتلة اجل�سم )P = 0.003(. مل تكن هناك اأي عالقة بني مقاومة الأن�سولني ووجود التاريخ العائلي ملر�س ال�سكري. اخلال�صة: هناك ارتفاع يف معدل انت�سار مقاومة الأن�سولني )%16( والبدانة )%26( يف �سباب طالب الطب العماين. يو�سى بتقدمي الن�سح جلميع الأفراد امل�سابني بالبدانة يف حماولة ملنع اأو تاأخري ظهور مر�س ال�سكري يف امل�ستقبل. مفتاح الكلمات: مقاومة الأن�سولني؛ معامل كتلة اجل�سم؛ البدانة؛ ال�سباب؛ �سلطنة عمان. Insulin Resistance and its Correlation with Risk Factors for Developing Diabetes Mellitus in 100 Omani Medical Students *Humaid H. Al-Farai,1 Issa Al-Aboodi,2 Azza Al-Sawafi,2 Noora Al-Busaidi,2 Nicholas Woodhouse2 BRIEF COMMUNICATION In recent decades, diabetes mellitus (DM) has become one of the most challenging medical issues worldwide. The World Health Organization (WHO) estimates a 190% increase in the number of people living with DM in Oman over the next 20 years, from 75,000 in 2000 to 217,000 in 2025.1 The distribution of chronic diseases and related risk factors among the Omani general population is similar to that of industrialised nations: 12% of the population have diabetes, 30% are overweight, 20% are obese, 41% have high cholesterol and 21% have metabolic syndrome.1 Insulin resistance (IR) is a major risk factor for developing metabolic syndrome. In clinical practice, IR refers to a state in which a given concentration of insulin is associated with a subnormal glucose response.2 In addition, IR is a precursor to the development of overt diabetes. It is therefore necessary to establish the magnitude of this problem in the Omani society and, armed with this knowledge, develop measures to delay or prevent the onset of DM in affected individuals. Insulin Resistance and its Correlation with Risk Factors for Developing Diabetes Mellitus in 100 Omani Medical Students e394 | SQU Medical Journal, August 2014, Volume 14, Issue 3 The aim of this study was to establish the prevalence of IR in a group of healthy, young Omani medical students and to correlate these findings with their body mass index (BMI) and the presence or absence of a positive family history (FH) of diabetes. Methods Omani students from the College of Medicine & Health Sciences of Sultan Qaboos University (SQU) in Muscat, Oman, were invited to participate in this study between May 2009 and February 2010. Investigators visited the students’ classes and explained the nature, benefits, risks and anticipated outcomes of the study. Smokers, diabetics, those taking regular medications and/or those with other medical problems were excluded from the study leaving 100 participants included in the study. The study group was comprised of 50 male and 50 female medical students between 20–25 years old in their fourth to sixth year of university and representing different regions of Oman. Most of the participants were from northern Omani governorates (Muscat, Al-Dakhliyah, Al-Batena, Al-Sharqiyah, Al- Dahahira and Musandam). Although, the participants represented the overall population of young Omanis in terms of geographical region, they did not give a fair representation of the overall young Omani population in terms of educational level. Each student anonymously filled out a questionnaire to determine the following: age; history of DM and other medical problems; regular medications taken; FH of DM with subtypes of first degree (mother, father, brother or sister) or second degree (grandfather, grandmother, uncle or aunt); smoking status, and weight, height and BMI measurements. Participants then underwent investigations to determine their fasting serum insulin and glucose levels. Insulin levels were measured with the Access® 2 Immunoassay System (Beckman Coulter, Inc., Brea, California, USA) using the chemiluminescence immunoassay principle while glucose levels were measured with the COBAS INTEGRA® 800 analyser (Roche Diagnostics Ltd., Basel, Switzerland) using the spectrophotometry principle. The clinical applications regarding the calculation of IR have not yet been standardised. However, the most reliable method to evaluate IR was chosen, the homeostasis model assessment-estimated insulin resistance (HOMA- IR). The HOMA-IR is calculated using the following formula: fasting insulin in µU/mL is multiplied by fasting glucose in mmol/L and divided by 22.5. The cut-off rate for abnormal values is between ≥2.1–2.7.3 A HOMA-IR level of >2.5 was considered abnormal. This level was decided upon based on the current clinical evidence that suggests using 2.5 as a cutoff point for IR.4 BMI was calculated by assessing each participant’s weight and height. Participants were then classified as either underweight (<18.5 kg/m2), normal (18.5–24.9 kg/m2) or overweight/obese (≥25 kg/m2). The data from the questionnaires and investigations were collected and analysed using the Statistical Package for the Social Sciences (SPSS), Table 1: Percentage of the sample of medical students according to insulin resistance, body mass index category and family history of diabetes (N = 100) Category Participants % Male n = 50 Female n = 50 Total IR 10 6 16 Underweight BMI 8 7 15 Normal BMI 27 32 59 Overweight or obese BMI 15 11 26 Family history of DM 37 37 74 IR = insulin resistance; BMI = body mass index; DM = diabetes mellitus. Figure 2: Percentage of the sample of medical students by body mass index category (N = 100). Figure 1: Percentage of the sample of medical students by insulin group (N = 100). Humaid H. Al-Farai, Issa Al-Aboodi, Azza Al-Sawafi, Noora Al-Busaidi and Nicholas Woodhouse brief communication | e395 Version 16 (IBM Corp., Chicago, Illinois, USA), using the Pearson’s Chi-squared test, Student’s t-test and Pearson product-moment correlation coefficient. A P value of <0.05 was considered statistically significant and a 95% confidence interval (CI) was used. Fully informed written consent was obtained from each participant. The study was approved by the Medical Research & Ethics Committee of the College of Medicine & Health Sciences at SQU. Results The data showed a high prevalence of IR (16%) among the 100 healthy subjects [Table 1 and Figure 1]. The 95% CI for the IR of the students was 2.99–4.19 and the mean was 3.59. There was a high prevalence of obesity (26%) among the sample, while 59% of the participants had a normal BMI and 15% were underweight [Figure 2]. IR was significantly associated with a high BMI (P = 0.003). Obesity was the main determinant of the degree of IR, while all subjects with a BMI of ≤21Kg/ m2 had no IR [Figure 3]. A large majority students (74%) had a positive FH of DM at either the first degree, second degree or both [Figure 4]. The results showed no correlation between IR and a positive FH of DM (P = 0.771). Discussion The current study found a high prevalence (26%) of obese and overweight Omani students. This finding strongly supports a recent study conducted among 202 Omani students of both genders which found that approximately 28% were overweight or obese.5 In addition, 16% of the subjects was found to have IR. The association between IR and BMI was statistically significant and no student with a BMI of ≤21 kg/m2 had a raised IR.5 This finding is consistent with previous studies demonstrating that obesity is one of the most important risk factors for developing IR.6,7 Out of the 16 students with IR and a mean BMI of 28.02 kg/m2, 10 were male and six were female. However, the significant association between IR and high BMI in terms of gender was biased due to the small sample size. A positive FH for DM is a controversial contributing risk factor for developing IR and DM. Some research has demonstrated a significant association between a positive FH of DM and IR,8 whereas other studies strongly disagree.9,10 In the current study, 74% of participants had a FH of DM at either the first degree, second degree or both. However, the association between IR and a FH of DM was not statistically significant. It is difficult to conclude either the presence or absence of an association between IR and a positive FH of DM from the current study as almost two-thirds of the sample had a positive FH. This may have masked the significant association between these risk factors. Awareness of IR and the associated risk of developing DM, as well as the strong association of these variables with obesity, will help improve Oman’s healthcare and patient outcomes. The primary prevention of DM should occur through lifestyle modifications, including improvements in diet and levels of physical exercise. The data in this study underscore the need for public education and awareness of these issues. A genetic predisposition for type 2 (T2) DM is a very important contributing risk factor; there are increasing reports of several mutations associated with the development of T2DM, such as the PPARG and CAPN10 genes.11,12 However, certain ethnic groups have specific genes that increase the risk of developing T2DM. For example, the Chinese population exhibits Figure 3: Significant direct correlation between body mass index and insulin resistance among the sample of medical students (N = 100). Figure 4: Number of students with and without a family history of diabetes (N = 100). Insulin Resistance and its Correlation with Risk Factors for Developing Diabetes Mellitus in 100 Omani Medical Students e396 | SQU Medical Journal, August 2014, Volume 14, Issue 3 the presence of the TCF7L2 gene, which puts them at increased risk for DM.13 However, further studies with larger samples are needed, including studies to evaluate other factors like genetic determinants, especially in those who test positive for IR. The IR-positive individuals among the study population will continue to be followed-up in the coming years so as to measure the true likelihood of them developing DM. All of the volunteers’ data and contact detils have been preserved for future longitudinal studies. Such studies would help healthcare professionals in the early identification and treatment of patients who are at risk of developing DM. Conclusion The prevalence of IR in healthy Omani medical students was found to be quite high in this study. Obesity was also prevalent and there was a direct correlation between BMI and IR. Significant IR was not seen in those with a BMI of 21 or less. The authors recommend efforts to reduce the prevalence of obesity, especially among young people, by promoting a healthy diet and physical exercise. This will reduce the prevalence of IR and the future risk of DM. References 1. Al-Lawati JA, Mabry R, Mohammed AJ. Addressing the threat of chronic diseases in Oman. Prev Chronic Dis 2008; 5:A99. 2. Moller DE, Flier JS. Insulin resistance: Mechanisms, syndromes, and implications. N Engl J Med 1991; 325:938–48. doi: 10.1056/ NEJM199109263251307. 3. Lebovitz HE. Clinician’s Manual on Insulin Resistance: The Dysmetabolic Syndrome. Bejing, China: Science Press Inc., 2002. P.5. 4. Singh Y, Garg MK, Tandon N, Marwaha RK. A study of insulin resistance by HOMA-IR and its cut-off value to identify metabolic syndrome in urban Indian adolescents. 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