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Dive into the research topics where Omar S. Al-Attas is active.

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Featured researches published by Omar S. Al-Attas.


BMC Medicine | 2011

Diabetes mellitus type 2 and other chronic non-communicable diseases in the central region, Saudi Arabia (riyadh cohort 2): a decade of an epidemic

Nasser M. Al-Daghri; Omar S. Al-Attas; Majed S. Alokail; Khalid M. Alkharfy; Mansour Yousef; Shaun Sabico; George P. Chrousos

BackgroundFollow-up epidemiologic studies are needed to assess trends and patterns of disease spread. No follow-up epidemiologic study has been done in the Kingdom of Saudi Arabia to assess the current prevalence of major chronic, noncommunicable diseases, specifically in the urban region, where modifiable risk factors remain rampant. This study aims to fill this gap.MethodsA total of 9,149 adult Saudis ages seven to eighty years (5,357 males (58.6%) and 3,792 females (41.4%)) were randomly selected from the Riyadh Cohort Study for inclusion. Diagnosis of type 2 diabetes mellitus (DMT2) and obesity were based on the World Health Organization definitions. Diagnoses of hypertension and coronary artery disease (CAD) were based on the Seventh Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure and American Heart Association criteria, respectively.ResultsThe overall crude prevalence of DMT2 was 23.1% (95% confidence interval (95% CI) 20.47 to 22.15). The age-adjusted prevalence of DMT2 was 31.6%. DMT2 prevalence was significantly higher in males, with an overall age-adjusted prevalence of 34.7% (95% CI 32.6 to 35.4), than in females, who had an overall age-adjusted prevalence of 28.6% (95% CI 26.7 to 29.3) (P < 0.001). The overall crude prevalence of obesity was 31.1% (95% CI 30.1 to 32.0). The age-adjusted prevalence of obesity was 40.0%. The prevalence of obesity was higher in females, with an overall prevalence of 36.5% (95% CI 35.1 to 37.83), than in males (25.1% (95% CI 23.7 to 26.3)) (P < 0.001). The age-adjusted prevalence of hypertension and CAD were 32.6% (95% CI 31.7 to 33.6) and 6.9% (95% CI 6.4 to 7.4), respectively.ConclusionComparisons of our findings with earlier data show that the prevalence of DMT2, hypertension and CAD in Riyadh, Saudi Arabia, has alarmingly worsened. Aggressive promotion of public awareness, continued screening and early intervention are pivotal to boosting a positive response.


Diabetes Care | 2012

High Fat Intake Leads to Acute Postprandial Exposure to Circulating Endotoxin in Type 2 Diabetic Subjects

A. L. Harte; Madhusudhan C. Varma; Gyanendra Tripathi; K. C. McGee; Nasser M. Al-Daghri; Omar S. Al-Attas; Shaun Sabico; J. P. O'Hare; Antonio Ceriello; Ponnusamy Saravanan; S. Kumar; Philip G. McTernan

OBJECTIVE To evaluate the changes in circulating endotoxin after a high–saturated fat meal to determine whether these effects depend on metabolic disease state. RESEARCH DESIGN AND METHODS Subjects (n = 54) were given a high-fat meal (75 g fat, 5 g carbohydrate, 6 g protein) after an overnight fast (nonobese control [NOC]: age 39.9 ± 11.8 years [mean ± SD], BMI 24.9 ± 3.2 kg/m2, n = 9; obese: age 43.8 ± 9.5 years, BMI 33.3 ± 2.5 kg/m2, n = 15; impaired glucose tolerance [IGT]: age 41.7 ± 11.3 years, BMI 32.0 ± 4.5 kg/m2, n = 12; type 2 diabetic: age 45.4 ± 10.1 years, BMI 30.3 ± 4.5 kg/m2, n = 18). Blood was collected before (0 h) and after the meal (1–4 h) for analysis. RESULTS Baseline endotoxin was significantly higher in the type 2 diabetic and IGT subjects than in NOC subjects, with baseline circulating endotoxin levels 60.6% higher in type 2 diabetic subjects than in NOC subjects (P < 0.05). Ingestion of a high-fat meal led to a significant rise in endotoxin levels in type 2 diabetic, IGT, and obese subjects over the 4-h time period (P < 0.05). These findings also showed that, at 4 h after a meal, type 2 diabetic subjects had higher circulating endotoxin levels (125.4%↑) than NOC subjects (P < 0.05). CONCLUSIONS These studies have highlighted that exposure to a high-fat meal elevates circulating endotoxin irrespective of metabolic state, as early as 1 h after a meal. However, this increase is substantial in IGT and type 2 diabetic subjects, suggesting that metabolic endotoxinemia is exacerbated after high fat intake. In conclusion, our data suggest that, in a compromised metabolic state such as type 2 diabetes, a continual snacking routine will cumulatively promote their condition more rapidly than in other individuals because of the greater exposure to endotoxin.


Cardiovascular Diabetology | 2009

Changes in endotoxin levels in T2DM subjects on anti-diabetic therapies

Omar S. Al-Attas; Nasser M. Al-Daghri; Khalid Al-Rubeaan; Nancy F. da Silva; Shaun Sabico; S. Kumar; Philip G. McTernan; A. L. Harte

IntroductionChronic low-grade inflammation is a significant factor in the development of obesity associated diabetes. This is supported by recent studies suggesting endotoxin, derived from gut flora, may be key to the development of inflammation by stimulating the secretion of an adverse cytokine profile from adipose tissue.AimsThe study investigated the relationship between endotoxin and various metabolic parameters of diabetic patients to determine if anti-diabetic therapies exerted a significant effect on endotoxin levels and adipocytokine profiles.MethodsFasting blood samples were collected from consenting Saudi Arabian patients (BMI: 30.2 ± (SD)5.6 kg/m2, n = 413), consisting of non-diabetics (ND: n = 67) and T2DM subjects (n = 346). The diabetics were divided into 5 subgroups based on their 1 year treatment regimes: diet-controlled (n = 36), metformin (n = 141), rosiglitazone (RSG: n = 22), a combined fixed dose of metformin/rosiglitazone (met/RSG n = 100) and insulin (n = 47). Lipid profiles, fasting plasma glucose, insulin, adiponectin, resistin, TNF-α, leptin, C-reactive protein (CRP) and endotoxin concentrations were determined.ResultsRegression analyses revealed significant correlations between endotoxin levels and triglycerides (R2 = 0.42; p < 0.0001); total cholesterol (R2 = 0.10; p < 0.001), glucose (R2 = 0.076; p < 0.001) and insulin (R2 = 0.032; p < 0.001) in T2DM subjects. Endotoxin showed a strong inverse correlation with HDL-cholesterol (R2 = 0.055; p < 0.001). Further, endotoxin levels were elevated in all of the treated diabetic subgroups compared with ND, with the RSG treated diabetics showing significantly lower endotoxin levels than all of the other treatment groups (ND: 4.2 ± 1.7 EU/ml, RSG: 5.6 ± 2.2 EU/ml). Both the met/RSG and RSG treated groups had significantly higher adiponectin levels than all the other groups, with the RSG group expressing the highest levels overall.ConclusionWe conclude that sub-clinical inflammation in T2DM may, in part, be mediated by circulating endotoxin. Furthermore, that whilst the endotoxin and adipocytokine profiles of diabetic patients treated with different therapies were comparable, the RSG group demonstrated significant differences in both adiponectin and endotoxin levels. We confirm an association between endotoxin and serum insulin and triglycerides and an inverse relationship with HDL. Lower endotoxin and higher adiponectin in the groups treated with RSG may be related and indicate another mechanism for the effect of RSG on insulin sensitivity.


Metabolism-clinical and Experimental | 2012

Modest reversal of metabolic syndrome manifestations with vitamin D status correction: a 12-month prospective study.

Nasser M. Al-Daghri; Khalid M. Alkharfy; Yousef Al-Saleh; Omar S. Al-Attas; Majed S. Alokail; Abdulaziz Al-Othman; Osama Moharram; Emad El-Kholie; Shaun Sabico; S. Kumar; George P. Chrousos

Numerous cross-sectional studies have noted significant negative associations between circulating levels of 25-hydroxyvitamin D and cardiometabolic risk factors, highlighting potential extraskeletal functions of this sterol hormone. Prospective studies, however, have been limited; and hence, no cause-and-effect relations can be inferred. This study aims to determine whether vitamin D status correction can reverse already established manifestations of the metabolic syndrome (MetS). A total of 59 adult nondiabetic, overweight, and obese Saudis (31 male, 28 female) were prospectively enrolled in this 1-year interventional study. Anthropometry and biochemical evaluation were performed, including determination of serum 25-hydroxyvitamin D, calcium, and phosphorous concentrations, as well as fasting blood glucose and lipid profile. Subjects were advised to regularly expose themselves to sunlight and increase intake of vitamin D-rich foods. All measurements were repeated 6 and 12 months later. At the initial baseline visit, the prevalence of both low high-density lipoprotein cholesterol and hypertension was significantly increased among patients with 25-vitamin D deficiency (P < .05), even after adjusting for sex and body mass index. Overall prevalence of MetS patients by the modified National Health and Nutrition Examination Survey Adult Treatment Panel III definition decreased from 25.2% to 13.0%; and this was largely due to a parallel decrease in the prevalence of low high-density lipoprotein cholesterol, triglycerides, and hypertension. Optimization of vitamin D status through sun exposure and increased intake of a vitamin D-rich diet can lead to an improved cardiometabolic profile, offering a promising nonpharmacologic approach in the prevention of MetS manifestations.


Cardiovascular Diabetology | 2005

Serum resistin is associated with C-reactive protein and LDL- cholesterol in type 2 diabetes and coronary artery disease in a Saudi population

Nasser M. Al-Daghri; R. Chetty; P. G. McTernan; K. Al-Rubean; Omar S. Al-Attas; Alan Jones; S. Kumar

AimsResistin is an adipocyte-derived factor implicated in obesity-associated type 2 diabetes (T2DM). This study examines the association between human serum resistin, T2DM and coronary heart disease.MethodsOne hundred and fourteen Saudi Arabian patients (male: female ratio 46:68; age 51.4 (mean ± SD)11.7 years; median and range: 45.59 (11.7) years and BMI: 27.1 (mean ± SD) 8.1 Kgm2 median and range: 30.3 (6.3) were studied. Serum resistin and C-reactive protein (CRP), a marker of inflammation CRP levels, were measured in all subjects. (35 patients had type 2 diabetes mellitus (T2DM); 22 patients had coronary heart disease (CHD).ResultsSerum resistin levels were 1.2-fold higher in type 2 diabetes and 1.3-fold higher in CHD than in controls (p = 0.01). In addition, CRP was significantly increased in both T2DM and CHD patients (p = 0.007 and p = 0.002 respectively). The use of regression analysis also determined that serum resistin correlated with CRP levels (p = 0.04, R2 0.045).ConclusionThe findings from this study further implicate resistin as a circulating protein associated with T2DM and CHD. In addition this study also demonstrates an association between resistin and CRP, a marker of inflammation in type 2 diabetic patients.


European Journal of Endocrinology | 2010

Adiposity and insulin resistance correlate with telomere length in middle-aged Arabs: the influence of circulating adiponectin

Omar S. Al-Attas; Nasser M. Al-Daghri; Majed S. Alokail; Assim A. Alfadda; Ahmed Bamakhramah; Shaun Sabico; Dave Pritlove; A. L. Harte; Gyanendra Tripathi; Philip G. McTernan; S. Kumar; George P. Chrousos

Objective Studies in obesity have implicated adipocytokines in the development of insulin resistance, which in turn may lead to accelerated aging. In this study, we determined associations of chromosomal telomere length (TL) to markers of obesity and insulin resistance in middle-aged adult male and female Arabs with and without diabetes mellitus type 2 (DMT2). Design and methods One hundred and ninety-three non-diabetic and DMT2 subjects without complications (97 males and 96 females) participated in this cross-sectional study. Clinical data, as well as fasting blood samples, were collected. Serum glucose and lipid profile were determined using routine laboratory methods. Serum insulin, leptin, adiponectin, resistin, tumor necrosis factor-α, and PAI-1 were quantified using customized multiplex assay kits. High sensitive C-reactive protein (hsCRP) and angiotensin II (ANG II) were measured using ELISAs. Circulating leukocyte TL was examined by quantitative real-time PCR. Results Circulating chromosomal leukocyte TL had significant inverse associations with body mass index (BMI), systolic blood pressure, fasting insulin, homeostasis model assessment of insulin resistance (HOMA-IR), low-density lipoprotein (LDL)- and total cholesterol, ANG II and hsCRP levels. Adiponectin, BMI, systolic blood pressure, and LDL cholesterol predicted 47% of the variance in TL (P<0.0001). HOMA-IR was the most significant predictor for TL in males, explaining 35% of the variance (P=0.01). In females, adiponectin accounted for 28% of the variance in TL (P=0.01). Conclusion Obesity and insulin resistance are associated with chromosomal TL among adult Arabs. Evidence of causal relations needs further investigation. The positive association of adiponectin to TL has clinical implications as to the possible protective effects of this hormone from accelerated aging.


Nutrition Research | 2002

Prevalence and risk factors of obesity and overweight in adult Saudi population

Mohammed A. Alsaif; Iman A. Hakim; Robin B Harris; Mansour Alduwaihy; Khalid Al-Rubeaan; Abdul Rahman Al-Nuaim; Omar S. Al-Attas

Abstract The objective of this study was to determine the prevalence and factors associated with obesity and overweight among adult Saudis using a national survey data from 1990 to 1993. The study population included 1652 men and 1619 women between 30 to 70 years of age. The prevalence of obesity was 49.15% in women and 29.94% in men, while the prevalence of being overweight but not obese was 31.55% in women and 41.91% in men. Obese and overweight women and men were significantly more likely to be between 40–49 years of age, with higher income, and hypertensive. Although physical activity was low in all women, obese women were significantly less likely to be engaged in any physical activity. Obese and overweight men were more likely to be non-smokers. Intervention strategies that target this population at risk are needed in Saudi Arabia.


BMC Pediatrics | 2012

Effect of physical activity and sun exposure on vitamin D status of Saudi children and adolescents

Abdulaziz Al-Othman; Sara Al-Musharaf; Nasser M. Al-Daghri; Soundararajan Krishnaswamy; Deqa S. Yusuf; Khalid M. Alkharfy; Yousef Al-Saleh; Omar S. Al-Attas; Majed S. Alokail; Osama Moharram; Shaun Sabico; George P. Chrousos

BackgroundAccumulating evidence suggests an increased prevalence of vitamin D deficiency in the Middle East. In this context, we aimed to determine whether the prevalence of vitamin D deficiency is related to degree of physical activity and sun exposure among apparently healthy Saudi children and adolescents, a little studied population.MethodsA total of 331 Saudi children aged 6–17 years (153 boys and 178 girls) were included in this cross sectional study. Levels of physical activity and sun exposure were determined using a standard questionnaire. Anthropometry, serum calcium and 25-(OH) vitamin D were analyzed.ResultsAll subjects were vitamin D deficient, the majority being moderately deficient (71.6%). Age was the single most significant predictor affecting 25 (OH) Vitamin D levels, explaining 21% of the variance perceived (p = 1.68 x 10-14). Age-matched comparisons revealed that for groups having the same amount of sun exposure, those with moderate or are physically active will have higher levels of vitamin D status, though levels in across groups remained deficient.ConclusionVitamin D deficiency is common among Saudi children and adolescents, and is influenced by both sun exposure and physical activity. Promotion of an active outdoor lifestyle among Saudi children in both homes and schools may counteract the vitamin D deficiency epidemic in this vulnerable population. Vitamin D supplementation is suggested in all groups, including those with the highest sun exposure and physical activity.


Regulatory Peptides | 2012

GLP-1 analogue, Liraglutide protects human umbilical vein endothelial cells against high glucose induced endoplasmic reticulum stress

Bruno Schisano; A. L. Harte; Konstantinos Lois; Ponnusamy Saravanan; Nasser M. Al-Daghri; Omar S. Al-Attas; Lotte Bjerre Knudsen; Philip McTernan; Antonio Ceriello; Gyanendra Tripathi

BACKGROUND AND PURPOSE Hyperglycemia induced endoplasmic reticulum (ER) stress in diabetic vascular cells is considered an increasingly important factor for the genesis and development of atherosclerosis and cardiovascular complications. This study investigated firstly, the effect of hyperglycemia in ER stress induction in Human Umbilical Vein Endothelial Cells (HUVECs) and secondly, the impact of Glucagon like petide-1 (GLP-1) analogue, Liraglutide, in reducing ER stress in HUVECs exposed to high glucose (HG). EXPERIMENTAL APPROACH HUVECs were incubated for 12 hr in 5 mmol/L normal glucose (NG) or in 25 mmol/L (HG) glucose with or without different concentrations of Liraglutide (1 nM, 10 nM or 100 nM) and components of ER stress pathways studied, using western blotting, to assess their expression levels. KEY RESULTS Our data confirmed that exposure of HUVECs to HG up-regulated both up- (Bip/Grp78, PERK and IRE1α) and downstream (Calnexin, PDI and Ero1-Lα) markers of ER stress compared with control. Furthermore, Liraglutide showed a dose dependent capacity in preventing the onset of ER stress in HUVECs, with a maximum activity at 100 nM. HG also upregulated proapoptotic PUMA protein levels compared to controls. Interestingly, Liraglutide also induced OPA1, a marker of mitochondrial fusion, in a dose dependent manner. CONCLUSIONS AND IMPLICATIONS Liraglutide prevented the onset of ER stress in human endothelial cells exposed to HG. Our data suggest that Liraglutide may exert its effects by inducing mitochondrial fusion processes, thus preventing HG induced mitochondrial fragmentation and apoptosis in human endothelial cells.


European Journal of Clinical Investigation | 2013

Visceral adiposity index is highly associated with adiponectin values and glycaemic disturbances

Nasser M. Al-Daghri; Omar S. Al-Attas; Majed S. Alokail; Khalid M. Alkharfy; Paris Charalampidis; Sarantis Livadas; Anastasios Kollias; Shaun Sabico; George P. Chrousos

Visceral Adiposity Index (VAI) is a gender‐specific mathematical index estimated with the use of simple anthropometric (body mass index and waist circumference) and biochemical (triglycerides and high density lipoprotein cholesterol) parameters. Recent studies have shown that VAI reflects accurately the degree of visceral adiposity and insulin resistance. However, up to now, VAI has not been evaluated if it correlates with carbohydrate metabolism disorders, as well as with adipokine secretion from the fat mass.

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George P. Chrousos

National and Kapodistrian University of Athens

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S. Kumar

University of Warwick

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