Publications (30)70.43 Total impact
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Article: Graphene versus Multi-Walled Carbon Nanotubes for Electrochemical Glucose Biosensing
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ABSTRACT: A simple procedure was developed for the fabrication of electrochemical glucose biosensors using glucose oxidase (GOx), with graphene or multi-walled carbon nanotubes (MWCNTs). Graphene and MWCNTs were dispersed in 0.25% 3-aminopropyltriethoxysilane (APTES) and drop cast on 1% KOH-pre-treated glassy carbon electrodes (GCEs). The EDC (1-ethyl-(3-dimethylaminopropyl) carbodiimide)-activated GOx was then bound covalently on the graphene- or MWCNT-modified GCE. Both the graphene- and MWCNT-based biosensors detected the entire pathophysiological range of blood glucose in humans, 1.4–27.9 mM. However, the direct electron transfer (DET) between GOx and the modified GCE’s surface was only observed for the MWCNT-based biosensor. The MWCNT-based glucose biosensor also provided over a four-fold higher current signal than its graphene counterpart. Several interfering substances, including drug metabolites, provoked negligible interference at pathological levels for both the MWCNT- and graphene-based biosensors. However, the former was more prone to interfering substances and drug metabolites at extremely pathological concentrations than its graphene counterpart.Materials 03/2013; 6(3):1011. · 1.68 Impact Factor -
Article: ACE I/D and MTHFR C677T polymorphism are significantly associated with type 2 diabetes in Arab ethnicity: A Meta- analysis.
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ABSTRACT: In this meta-analysis study, SNPs were investigated for their association with Type 2 Diabetes (T2D) in both Arab and Caucasian ethnicities. A total of 55 SNPs were analyzed, of which 11 fulfilled the selection criteria, and were used for analysis. It was found that TCF7L2 rs7903146 was significantly associated with a pooled OR of 1.155 (95%C.I.=1.059-1.259), p<0.0001 and I2=78.30% among the Arab population, whereas among Caucasians, the pooled OR was 1.45 (95%C.I.=1.386-1.516) , p<0.0001 and I2=77.20%. KCNJ11 rs5219 was significantly associated in both the populations with a pooled OR of 1.176(1.092-1.268), p<0.0001 and I2=32.40% in Caucasians and a pooled OR of 1.28(1.111-1.475), p=0.001 among Arabs. The ACE I/D polymorphism was found to be significantly associated with a pooled OR of 1.992 (95%C.I.=1.774-2.236), p<0.0001and I2=83.20% among Arab population, whereas among Caucasians, the pooled OR was 1.078 (95%C.I.=0.993-1.17), p=0.073 and I2=0%. Similarly, MTHFR C677T polymorphism was also found to be significantly associated among Arabs with a pooled OR of 1.924 (95%C.I.=1.606-2.304), p<0.0001 and I2=27.20%, whereas among Caucasians, the pooled OR was 0.986 (95%C.I.=0.868-1.122), p=0.835 and I2=0%. Meanwhile PPARG-2 Pro12Ala, CDKN2A/2B rs10811661, IGF2BP2 rs4402960, HHEX rs7923837, CDKAL1 rs7754840, EXT2 rs1113132 and SLC30A8 rs13266634 were found to have no significant association with T2D among Arabs. In conclusion, it seems from this study that both Arabs and Caucasians have different SNPs associated with T2D. Moreover; this study sheds light on the profound necessity for further investigations addressing the question of the genetic components of T2D in Arabs.Gene 02/2013; · 2.34 Impact Factor -
Article: Mediatorless amperometric glucose biosensing using 3-aminopropyltriethoxysilane-functionalized graphene.
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ABSTRACT: A mediatorless glucose biosensor was developed by the immobilization of glucose oxidase (GOx) to graphene-functionalized glassy carbon electrode (GCE). The surface of GCE was functionalized with graphene by incubating it with graphene dispersed in 3-aminopropyltriethoxysilane (APTES), which acted both as a dispersion agent for graphene and as an amine surface modification agent for GCE and graphene. This was followed by the covalent binding of GOx to graphene-functionalized GCE using 1-ethyl-3-[3-dimethylaminopropyl]carbodiimide hydrochloride (EDC) based crosslinking. Graphene provided signal enhancement by providing greater surface area for GOx binding, while APTES-functionalization led to a higher GOx immobilization density by providing free amino groups for crosslinking. The developed biosensor used a redox potential of -0.45V (vs. Ag/AgCl) for detecting glucose in the diabetic pathophysiological range 0.5-32mM. There was no interference from endogenous electroactive substances and drug metabolites. The developed biosensor was further validated for detecting blood glucose in commercial artificial blood glucose linearity standards in the range 1.4-27.9mM. Therefore, it is ideal for diabetic blood glucose monitoring. The developed bioanalytical procedure for preparation of GOx-bound graphene-functionalized GCEs had high production reproducibility and high storage stability, which is appropriate for the commercial mass production of enzyme-bound electrodes.Talanta 09/2012; 99:22-8. · 3.79 Impact Factor -
Article: Rapid and simple preparation of a reagentless glucose electrochemical biosensor.
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ABSTRACT: A rapid and simple procedure was developed for the preparation of a highly stable and leach-proof glucose oxidase (GOx)-bound glassy carbon electrode (GCE). Crosslinked GOx via glutaraldehyde was drop-cast on a KOH-pretreated GCE followed by drop-casting of 3-aminopropyltriethoxysilane (APTES) to form a stable bioactive layer. At -0.45 V, the biosensor exhibited a wide dynamic detection range of 0.5-48 mM for commercial glucose and 1.3-28.2 mM for Sugar-Chex blood glucose linearity standards. Several endogenous electroactive substances and drug metabolites commonly found in blood were tested and provoked no signal response. To our knowledge, the developed procedure is the most rapid method for preparing a glucose biosensor. The biosensor suffered no biofouling after 7 days of immersion in Sugar-Chex blood glucose. With excellent production reproducibility, GOx-bound electrodes stored dry at room temperature retained their initial activity after several weeks.The Analyst 07/2012; 137(16):3800-5. · 4.23 Impact Factor -
Article: Technology behind commercial devices for blood glucose monitoring in diabetes management: a review.
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ABSTRACT: The blood glucose monitoring devices (BGMDs) are an integral part of diabetes management now-a-days. They have evolved tremendously within the last four decades in terms of miniaturization, rapid response, greater specificity, simplicity, minute sample requirement, painless sample uptake, sophisticated software and data management. This article aims to review the developments in the technologies behind commercial BGMD, especially those in the areas of chemistries, mediators and other components. The technology concerns, on-going developments and future trends in blood glucose monitoring (BGM) are also discussed.Analytica chimica acta 10/2011; 703(2):124-36. · 4.31 Impact Factor -
Article: Correlation between serum electrolytes and fasting glucose and Hb1Ac in Saudi diabetic patients.
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ABSTRACT: In subjects with impaired insulin action, alterations of the serum sodium and potassium concentrations have been reported. The resulting cationic imbalance, along with the osmotic effect of the elevated sugar levels, could influence the course of diabetes mellitus management. Therefore, this study was conducted to compare the fasting blood glucose and HbA1c levels with those of the serum electrolytes. Blood samples were collected for assessment of HbA1c, fasting blood glucose (FBS), and electrolytes using different automated methods. A significant association between the serum sodium and FBS levels among types 1 and 2 insulin-treated patients, and type 2 oral agent patients was observed. A total of 138 diabetic subjects were randomly selected from any gender aged between 25 and 65 years at the University Diabetes Center, King Saud University, Riyadh KSA. The subjects were classified into types 1 or 2 DM using ADA criteria. Blood samples were collected for assessment of HbA1c, FBS, and electrolytes using different automated methods. It showed a significant association between serum sodium, FBS among type 1, type 2 insulin treated, and type 2 oral agent groups. However, the association of sodium and HbA1c was insignificant when analyzed individually. A statistically significant association (P < 0.001) was observed between the levels of serum sodium and the fasting blood glucose levels. This study demonstrated significant reduction in serum sodium level among types 1 or 2 diabetic patients especially among insulin-treated patients. No significant association was demonstrated by serum potassium with FBS and degree of diabetes control.Biological trace element research 08/2011; 144(1-3):463-8. · 1.92 Impact Factor -
Article: Lung functions in poorly controlled type 1 Saudi diabetic children and adolescents.
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ABSTRACT: To determine the lung function among Saudi type 1 diabetes mellitus (T1DM) children and adolescents. This study was conducted in the Department of Pediatrics, Division of Pediatric Pulmonology and University Diabetes Centre, College of Medicine, King Saud University, Riyadh, Kingdom of Saudi Arabia from December 2008 to July 2010. A group of 52 (26 male and 26 female) volunteer T1DM children were recruited with an age range from 8-14 years (mean 12.05 +/- 1.42 years), mean duration of disease of 5.25 +/- 0.47 years, and mean glycosylated hemoglobin of 11.27 +/- 0.31%. Spirometry was performed on an Electronic Spirometer (Compact Vitalograph, Stockwell, London, UK). Pulmonary function in children with diabetes showed significant lower mean values of actual lung function parameters forced vital capacity (FVC), peak expiratory flow (PEF), and maximum mid expiratory flow rate (MMEF) compared to their predicted values. However, there was no significant reduction in the actual forced expiratory volume in the first second (FEV1), and FEV1/FVC% compared to their predicted values. The actual lung function data among Saudi T1DM children and adolescents showed significantly lower values of FVC, PEF, and MMEF compared to the predicted lung function data.Saudi medical journal 08/2011; 32(8):778-83. · 0.52 Impact Factor -
Article: Sulfo-N-hydroxysuccinimide interferes with bicinchoninic acid protein assay.
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ABSTRACT: This study revealed a major interference from sulfo-N-hydroxysuccinimide (sulfo-NHS) in the bicinchoninic acid (BCA) protein assay. Sulfo-NHS, a common reagent used in bioconjugation and analytical biochemistry, exhibited absorbance signals and absorbance peaks at 562 nm, comparable to bovine serum albumin (BSA). However, the combined absorbance of sulfo-NHS and BSA was not strictly additive. The sulfo-NHS interference was suggested to be caused by the reduction of Cu(2+) in the BCA Kit's reagent B (4% cupric sulfate) in a manner similar to that of the protein.Analytical Biochemistry 06/2011; 417(1):156-8. · 3.00 Impact Factor -
Article: Delivery of drugs and biomolecules using carbon nanotubes
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ABSTRACT: Carbon nanotubes (CNTs) have emerged as one of the most advanced nanovectors for the highly efficient delivery of drugs and biomolecules. They offer several appealing features such as large surface areas with well defined physico-chemical properties as well as unique optical and electrical properties. They can be conjugated non-covalently or covalently with drugs, biomolecules and nanoparticles. Albeit some pending concerns about their toxicity in vitro and in vivo, functionalized CNTs appear to exhibit very low toxicity and are not immunogenic. Thus, they could be promising carriers with a great potential for the devel-opment of a new-generation delivery system for drugs and biomolecules. There have been significant advances in the field of CNT-based drug delivery, especially in the specific tar-geting of anticancer and anti-inflammatory drugs for tissues and organs in the body, where their therapeutic effect is highly required. Other promising applications are the delivery of DNA, RNA and proteins.Carbon 05/2011; 49:4077-4097. · 5.38 Impact Factor -
Article: Advances in carbon nanotube based electrochemical sensors for bioanalytical applications.
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ABSTRACT: Electrochemical (EC) sensing approaches have exploited the use of carbon nanotubes (CNTs) as electrode materials owing to their unique structures and properties to provide strong electrocatalytic activity with minimal surface fouling. Nanofabrication and device integration technologies have emerged along with significant advances in the synthesis, purification, conjugation and biofunctionalization of CNTs. Such combined efforts have contributed towards the rapid development of CNT-based sensors for a plethora of important analytes with improved detection sensitivity and selectivity. The use of CNTs opens an opportunity for the direct electron transfer between the enzyme and the active electrode area. Of particular interest are also excellent electrocatalytic activities of CNTs on the redox reaction of hydrogen peroxide and nicotinamide adenine dinucleotide, two major by-products of enzymatic reactions. This excellent electrocatalysis holds a promising future for the simple design and implementation of on-site biosensors for oxidases and dehydrogenases with enhanced selectivity. To date, the use of an anti-interference layer or an artificial electron mediator is critically needed to circumvent unwanted endogenous electroactive species. Such interfering species are effectively suppressed by using CNT based electrodes since the oxidation of NADH, thiols, hydrogen peroxide, etc. by CNTs can be performed at low potentials. Nevertheless, the major future challenges for the development of CNT-EC sensors include miniaturization, optimization and simplification of the procedure for fabricating CNT based electrodes with minimal non-specific binding, high sensitivity and rapid response followed by their extensive validation using "real world" samples. A high resistance to electrode fouling and selectivity are the two key pending issues for the application of CNT-based biosensors in clinical chemistry, food quality and control, waste water treatment and bioprocessing.Biotechnology advances 10/2010; 29(2):169-88. · 8.25 Impact Factor -
Article: Interfacing carbon nanotubes with living mammalian cells and cytotoxicity issues.
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ABSTRACT: The unique structures and properties of carbon nanotubes (CNTs) have attracted extensive investigations for many applications, such as those in the field of biomedical materials and devices, biosensors, drug delivery, and tissue engineering. Anticipated large-scale productions for numerous diversified applications of CNTs might adversely affect the environment and human health. For successful applications in the biomedical field, the issue of interfacing between CNTs and mammalian cells in vitro needs to be addressed before in vivo studies can be carried out systematically. We review the important studies pertaining to the internalization of CNTs into the cells and the culturing of cells on the CNT-based scaffold or support materials. The review will focus on the description of a variety of factors affecting CNT cytotoxicity: type of CNTs, impurities, lengths of CNTs, aspect ratios, dispersion, chemical modification, and assaying methods of cytotoxicity.Chemical Research in Toxicology 07/2010; 23(7):1131-47. · 3.78 Impact Factor -
Article: Sugar-sweetened carbonated beverage consumption correlates with BMI, waist circumference, and poor dietary choices in school children.
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ABSTRACT: The prevalence of obesity and overweight is increasing globally. Frequently coexisting with under-nutrition in developing countries, obesity is a major contributor to chronic disease, and will become a serious healthcare burden especially in countries with a larger percentage of youthful population. 35% of the population of Saudi Arabia are under the age of 16, and adult dietary preferences are often established during early childhood years. Our objective was to examine the dietary habits in relation to body-mass-index (BMI) and waist circumference (W_C), together with exercise and sleep patterns in a cohort of male and female Saudi school children, in order to ascertain whether dietary patterns are associated with obesity phenotypes in this population. 5033 boys and 4400 girls aged 10 to 19 years old participated in a designed Food Frequency Questionnaire. BMI and W_C measurements were obtained and correlated with dietary intake. The overall prevalence of overweight and obesity was 12.2% and 27.0% respectively, with boys having higher obesity rates than girls (P <or= 0.001). W_C and BMI was positively correlated with sugar-sweetened carbonated beverage (SSCB) intake in boys only. The association between male BMI and SSCB consumption was significant in a multivariate regression model (P < 0.0001). SSCB intake was positively associated with poor dietary choices in both males and females. Fast food meal intake, savory snacks, iced desserts and total sugar consumption correlated with SSCB intake in both boys (r = 0.39, 0.13, 0.10 and 0.52 respectively, P < 0.001) and girls (r = 0.45, 0.23, 0.16 and 0.55 respectively, P < 0.001). Older children reported eating significantly less fruit and vegetables than younger children; and less eggs, fish and cereals. Conversely, consumption of SSCB and sugar-sweetened hot beverages were higher in older versus younger children (P < 0.001). BMI and W_C were negatively correlated with hours of night-time sleep and exercise in boys, but only with night time sleep in girls, who also showed the lowest frequency of exercise. A higher intake of SSCB is associated with poor dietary choices. Male SSCB intake correlates with a higher W_C and BMI. Limiting exposure to SSCB could therefore have a large public health impact.BMC Public Health 01/2010; 10:234. · 2.00 Impact Factor -
Article: Sugar-sweetened carbonated beverage consumption correlates with BMI, waist circumference, and poor dietary choices in school children
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ABSTRACT: Abstract Background The prevalence of obesity and overweight is increasing globally. Frequently coexisting with under-nutrition in developing countries, obesity is a major contributor to chronic disease, and will become a serious healthcare burden especially in countries with a larger percentage of youthful population. 35% of the population of Saudi Arabia are under the age of 16, and adult dietary preferences are often established during early childhood years. Our objective was to examine the dietary habits in relation to body-mass-index (BMI) and waist circumference (W_C), together with exercise and sleep patterns in a cohort of male and female Saudi school children, in order to ascertain whether dietary patterns are associated with obesity phenotypes in this population. Methods 5033 boys and 4400 girls aged 10 to 19 years old participated in a designed Food Frequency Questionnaire. BMI and W_C measurements were obtained and correlated with dietary intake. Results The overall prevalence of overweight and obesity was 12.2% and 27.0% respectively, with boys having higher obesity rates than girls (P ≤ 0.001). W_C and BMI was positively correlated with sugar-sweetened carbonated beverage (SSCB) intake in boys only. The association between male BMI and SSCB consumption was significant in a multivariate regression model (P < 0.0001). SSCB intake was positively associated with poor dietary choices in both males and females. Fast food meal intake, savory snacks, iced desserts and total sugar consumption correlated with SSCB intake in both boys (r = 0.39, 0.13, 0.10 and 0.52 respectively, P < 0.001) and girls (r = 0.45, 0.23, 0.16 and 0.55 respectively, P < 0.001). Older children reported eating significantly less fruit and vegetables than younger children; and less eggs, fish and cereals. Conversely, consumption of SSCB and sugar-sweetened hot beverages were higher in older versus younger children (P < 0.001). BMI and W_C were negatively correlated with hours of night-time sleep and exercise in boys, but only with night time sleep in girls, who also showed the lowest frequency of exercise. Conclusions A higher intake of SSCB is associated with poor dietary choices. Male SSCB intake correlates with a higher W_C and BMI. Limiting exposure to SSCB could therefore have a large public health impact.BMC Public Health. 01/2010; -
Article: Design and development of a web-based Saudi National Diabetes Registry.
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ABSTRACT: Given that diabetes is an extremely common disorder in Saudi Arabia, the National Diabetes Registry was designed by King Saud University Hospital Diabetes Center in collaboration with King Faisal Specialist Hospital & Research Center, Riyadh, Saudi Arabia, in the year 2001. The aim of the registry is to identify risk factors related to diabetes and to provide statistics to public health programs and health care professionals for use in planning and evaluation. The registry was designed to provide information on the extent and nature of specific types of diabetes, diabetes complications, and treatment of diabetes in the Kingdom. The registry has been available since 2001, with major collaborations from 26 hospitals as part of Phase I in which 100,000 patient data is to be collected on a regional level from Ar-Riyadh before extending the program to other regions of Saudi Arabia. The web application was designed using relational database techniques along with on-line help topics to assist users to get acquainted with application functionalities. All Internet forms were designed with validation checks and appropriate messages to ensure quality of data. The security measures established within the application ensure that only authorized users can gain access to the functionalities of the registry at allowed times. Administrative features were designed to manage the registry-related operations easily. The diabetes registry has been in operation for almost 10 years, and around 67,000 patients have been registered to date. The Web-application offers an anytime-anywhere access to the registry's data, removing geographical boundaries and allowing the national registry to provide real-time data entry, updates, reporting, and mapping functionalities more easily. Merging related information in the form of databases can provide improved health care operations through instant access to data, ease of managing complex data structures, and creation of reports to be used by health care planners and hospital administrators.Journal of diabetes science and technology 01/2010; 4(6):1574-82. -
Article: Changes in endotoxin levels in T2DM subjects on anti-diabetic therapies.
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ABSTRACT: Chronic 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. The 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. Fasting 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-alpha, leptin, C-reactive protein (CRP) and endotoxin concentrations were determined. Regression 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. We 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.Cardiovascular Diabetology 04/2009; 8:20. · 3.35 Impact Factor -
Article: Genetic study of Saudi diabetes (GSSD): significant association of the KCNJ11 E23K polymorphism with type 2 diabetes.
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ABSTRACT: The E23K variant of KCNJ11 has been associated with type 2 diabetes (T2D) in several but not all populations studied. Thus far, despite a high incidence of T2D, the role of this variant in Arabs has not been established. We performed a case-control association study using 550 T2D Saudi patients (WHO criteria), and 335 controls (age>or=60; fasting plasma glucose<7 mmol/L). E23K genotyping was performed by using molecular beacon-based real time PCR assays. The difference in K or risk allele frequency of cases and controls was significant with an OR of 1.7 (p=0.0001). The K allele is more common among T2D patients (21%) than in the age and sex matched controls (13.6%). This was consistent with a likely eventual conversion to T2D of younger normoglycemic individuals as they grow older. Our results report for the first time a positive association of the E23K variant with T2D in an Arab population. Confirmation by a larger study is indicated.Diabetes/Metabolism Research and Reviews 02/2008; 24(2):137-40. · 3.37 Impact Factor -
Article: Weak or no association of TCF7L2 variants with Type 2 diabetes risk in an Arab population.
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ABSTRACT: The rs7903146 and rs12255372 variants of TCF7L2 have been strongly associated with type 2 diabetes (T2D) risk in most populations studied to date. Meta-analysis of 27 different studies has resulted in a global OR of 1.46 [1.42-1.51] (rs7903146 variant). Thus far, despite a high incidence of T2D, the role of this variant in Arabs has not been established. We performed a case-control association study using 522 Saudi T2D patients (WHO criteria), and 346 controls (age > 60; fasting plasma glucose < 7 mmol/L). Genotyping was performed by pyrosequencing. Statistical analyses were performed using SPSS version 13.0 for Windows (SPSS, Chicago, IL, USA). For rs7903146, the T allele frequency of the cases (0.415) was not different from that observed in the controls (0.405). The crude odds ratio (OR) was 1.04 with a 95% CI of 0.86-1.27 (P = 0.675). For rs12255372, the T allele frequency of the cases (0.368) was not different from that observed in the controls (0.355). Retrospective power calculations based upon an OR of 1.46 reported in a comprehensive meta-analysis of TCF7L2 risk, indicated this study was sufficiently powered (96.92%; alpha = 0.05) to detect an effect of similar magnitude to that reported for rs7903146. Our study is consistent with weak or no association of T2D in Arabs with the two TCF7L2 variants, however it cannot rule out an effect of other SNPs in this gene. Future studies in this population are required to confirm our findings and may indicate the presence of yet to be defined genetic risk factors for T2D.BMC Medical Genetics 01/2008; 9:72. · 2.33 Impact Factor -
Article: Weak or no association of TCF7L2 variants with Type 2 diabetes risk in an Arab population
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ABSTRACT: Abstract Background The rs7903146 and rs12255372 variants of TCF7L2 have been strongly associated with type 2 diabetes (T2D) risk in most populations studied to date. Meta-analysis of 27 different studies has resulted in a global OR of 1.46 [1.42–1.51] (rs7903146 variant). Thus far, despite a high incidence of T2D, the role of this variant in Arabs has not been established. Methods We performed a case-control association study using 522 Saudi T2D patients (WHO criteria), and 346 controls (age > 60; fasting plasma glucose < 7 mmol/L). Genotyping was performed by pyrosequencing. Statistical analyses were performed using SPSS version 13.0 for Windows (SPSS, Chicago, IL, USA). Results For rs7903146, the T allele frequency of the cases (0.415) was not different from that observed in the controls (0.405). The crude odds ratio (OR) was 1.04 with a 95% CI of 0.86–1.27 (P = 0.675). For rs12255372, the T allele frequency of the cases (0.368) was not different from that observed in the controls (0.355). Retrospective power calculations based upon an OR of 1.46 reported in a comprehensive meta-analysis of TCF7L2 risk, indicated this study was sufficiently powered (96.92%; α = 0.05) to detect an effect of similar magnitude to that reported for rs7903146. Conclusion Our study is consistent with weak or no association of T2D in Arabs with the two TCF7L2 variants, however it cannot rule out an effect of other SNPs in this gene. Future studies in this population are required to confirm our findings and may indicate the presence of yet to be defined genetic risk factors for T2D.BMC Medical Genetics. 01/2008; -
Article: Serum leptin and its relation to anthropometric measures of obesity in pre-diabetic Saudis.
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ABSTRACT: Little information is available on leptin concentrations in individuals with IGT. This study aims to determine and correlate leptin levels to anthropometric measures of obesity in pre-diabetic, (IFG and IGT), type 2 diabetic and normoglycaemic Saudis. 308 adult Saudis (healthy controls n = 80; pre-diabetes n = 86; Type 2 diabetes n = 142) participated. Anthropometric parameters were measured and fasting blood samples taken. Serum insulin was analysed, using a solid phase enzyme amplified sensitivity immunoassay and also leptin concentrations, using radio-immunoassay. The remaining blood parameters were determined using standard laboratory procedures. Leptin levels of diabetic and pre-diabetic men were higher than in normoglycaemic men (12.4 [3.2-72] vs 3.9 [0.8-20.0] ng/mL, (median [interquartile range], p = 0.0001). In females, leptin levels were significantly higher in pre-diabetic subjects (14.09 [2.8-44.4] ng/mL) than in normoglycaemic subjects (10.2 [0.25-34.8] ng/mL) (p = 0.046). After adjustment for BMI and gender, hip circumference was associated with log leptin (p = 0.006 with R2 = 0.086) among all subjects. Leptin is associated with measures of adiposity, hip circumference in particular, in the non-diabetic state among Saudi subjects. The higher leptin level among diabetics and pre-diabetics is not related to differences in anthropometric measures of obesity.Cardiovascular Diabetology 02/2007; 6:18. · 3.35 Impact Factor -
Article: The atherogenic and metabolic impact of non-HDL cholesterol versus other lipid sub-components among non-diabetic and diabetic Saudis.
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ABSTRACT: Several trials from different populations have reported that non-high density lipoprotein cholesterol (non-HDL-C) has more predictive power than low-density lipoprotein cholesterol (LDL-C) in detecting coronary heart disease (CHD) and none in any Arab community whose propensity to develop CHD is higher compared to other ethnicities. This study aims to determine and compare the impact of non-HDL-C versus other lipid parameters, in predicting coronary heart disease among diabetic versus non-diabetic adult Saudis and identify the lipid parameters which make a significant contribution in the development of coronary heart disease, diabetes mellitus, and metabolic syndrome. 733 adult Saudis were recruited and divided into groups of diabetics and non-diabetics. Each participant completed a questionnaire, underwent physical exam including 12-L ECG, and submitted a fasting blood sample where glucose and lipid parameters were analyzed using routine procedures. 462 subjects (age 45.03 +/- 11.52; BMI 28.91 +/- 6.07) were classified non-diabetics while the remaining 271 (age 52.73 +/- 11.45, BMI 30.15 +/- 6.62) were diabetics. 99 out of 465 (21.3%) of non-diabetics had CHD and 114 out of 271 (52.5%) in the diabetics. Non-HDL cholesterol was the best predictor among the non-diabetics (odds-ratio 2.89, CI 1.10-7.58, p-0.03). Total cholesterol was the highest single predictor for the development of CHD among the lipids (odds-ratio 1.36, CI 0.68-2.71, p-0.39) but HDL-cholesterol although small was significant (odds-ratio 0.52, CI 0.27-0.99, p-0.05). This study supports the use of non-HDL cholesterol as the more practical and reliable target for lipid lowering therapy among the Saudi population.Lipids in Health and Disease 02/2007; 6:9. · 2.17 Impact Factor
Top co-authors
Top Journals
Institutions
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2007–2013
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King Saud University
- • College of Medicine
- • College of Science
Riyadh, Mintaqat ar Riyad, Saudi Arabia
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2010–2011
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National University of Singapore
- Department of Physics
Singapore, Singapore
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2008–2010
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King Faisal Specialist Hospital & Research Centre
- Department of Biological and Medical Research
Jeddah, Mintaqat Makkah, Saudi Arabia -
King Abdulaziz University
Jeddah, Mintaqat Makkah, Saudi Arabia
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