Mohammed Hassan

To assess aerobic fitness in male and female adolescents using the multistage 20-metre shuttle run test and correlate it with selected fitness variables. The subjects comprised 83 girls and 64 boys aged 15-16 years, randomly selected from two segregated government schools in Muscat. After the pupils filled in a short questionnaire on their personal leisure time activities of the preceding week, their heights and weights were measured. Aerobic fitness was assessed by estimating each pupil's minimal oxygen uptake levels (VO2max) using the multistage 20-metre shuttle running test (20-MST). Boys spent more time than girls on leisure physical activities, television, computer and video games and the Internet. The estimated VO2max in both boys and girls showed high correlation with their weekly physical activities. The time spent on television and computer negatively correlated with VO2max in girls but not in boys. Girls had higher body mass index (BMI) and less VO2max compared to boys...

To investigate the association of 10 known common gene variants with susceptibility to type 2 diabetes mellitus (T2D) among Omanis. Using case-control design, a total of 992 diabetic patients and 294 normoglycemic Omani Arabs were genotyped, by an allelic discrimination assay-by-design TaqMan method on fast real time polymerase chain reaction system, for the following gene variants: KCNJ11 (rs5219), TCF7L2 (rs7903146), CDKAL1 (rs10946398), CDKN2A/B (rs10811661), FTO (rs9939609 and rs8050136), IGF2BP2 (rs4402960), SLC30A8 (rs13266634) CAPN10 (rs3792267) and HHEX (rs1111875). T2D patients were recruited from the Diabetes Clinic (n = 243) and inpatients (n = 749) at Sultan Qaboos Univesity Hospital (SQUH), Muscat, Oman. Adult control participants (n = 294) were volunteers from the community and from those visiting Family Medicine Clinic at SQU, for regular medical checkup. The difficulty in recruiting Omani participants with no family history of diabetes was the main reason behind the small number of control participants in this study. Almost all volunteers questioned had a relative with diabetes mellitus. Inspite of the small number of normoglycemic controls in this study, this sample was sufficient for detection of genes and loci for common alleles influencing T2D with an odds ratio of ≥ 1.3 reaching at least 80% power. Data was collected from June 2010 to February 2012. Using binary logistic regression analysis, four gene variants showed significant association with T2D risk: KCNJ11 (rs5219, P = 5.8 × 10(-6), OR = 1.74), TCF7L2 (rs7903146, P = 0.001, OR = 1.46), CDKAL1 (rs10946398, P = 0.002, OR = 1.44) and CDKN2A/B (rs10811661, P = 0.020, OR = 1.40). The fixation index analysis of these four gene variants indicated significant genetic differentiation between diabetics and controls {[KCNJ11 (rs5219), P < 0.001], [TCF7L2 (rs7903146), P < 0.001], [CDKAL1 (rs10946398), P…

To assess the clinical care of type 2 diabetes mellitus (T2D) patients at Sultan Qaboos University Hospital (SQUH), a countrywide tertiary referral center in Muscat, Oman. . We performed a retrospective, observational, cross-sectional study using a total of 673 Omani T2D patients from the Diabetes and Family Medicine Clinics at SQUH. We collected patient data from June 2010 to February 2012 from the Hospital Information System (HIS). Patients had to be Omani, aged more than 18 years old, and have T2D with active follow-up and at least three visits within one year to be included in the study. Ninety-three percent of the patients (n=622) were on oral hypoglycemic drugs and/or insulin, and 70% were on statins. Patients' anthropometric data, biochemical investigations, blood pressure, and duration of diabetes were recorded from the HIS. . Using the recommended standards and guidelines of medical care in diabetes (American Diabetes Association and the American National Cholesterol Education Program III NCDP NIII standards), we observed that 22% of the patients achieved a HbA1C goal of <7%, 47% achieved blood pressure goal of <140/80mm Hg, 48% achieved serum low density lipoprotein cholesterol goal of <2.6mmol/L, 67% achieved serum triglycerides goal of <1.7 mmol/L, 59% of males and 43% of females achieved high density lipoprotein cholesterol goals (males>1.0; females >1.3mmol/L). Almost 60% of the patients had urinary microalbumin/creatinine ratio within the normal range. . The clinical outcomes of the care that T2D patients get at SQUH were lower than those reported in Europe and North America. However, it is similar to those reported in other countries in the Arabian Gulf.

Obstructive Sleep Apnea (OSA) is the cessation of breathing during sleep due to the collapse of upper airway. Polysomnographic recording is a conventional method for detection of OSA. Although it provides reliable results, it is expensive and cumbersome. Thus, an advanced non-invasive signal processing based technique is needed. The main purpose of this work is to predict the severity of sleep apnea using an efficient wavelet-based spectral analysis method of the heart rate variability (HRV) to classify sleep apnea into three different levels (mild, moderate, and severe) according to its severity and to distinguish them from normal subjects. The standard FFT spectrum analysis method and the soft-decision wavelet-based technique are to be used in this work in order to rank patients to full polysomnography. Data of 20 normal subjects and 20 patients with mild apnea and 20 patients with moderate apnea and 20 patients of severe apnea are used in this study. The data is obtained from the sleep laboratory of Sultan Qaboos University hospital in Oman. Four different classification versions have been used in this work. Accuracy result of 90% was obtained between severe and normal subjects and 85% between mild and normal and 75% between severe and moderate and 83.75% between normal and patients. The VLF/LF power spectral ratio of the wavelet-based soft-decision analysis of the RRI data after a high-pass filter resulted in the best accuracy of classification in all versions.

Plasma levels of adiponectin are decreased in type 2 diabetes, obesity and hypertension. Our aim was to use a family-based analysis to identify the genetic variants of the adiponectin (ADIPOQ) gene that are associated with obesity, insulin resistance, dyslipidemia and hypertension, among Arabs. We screened 328 Arabs in one large extended family for single nucleotide polymorphisms (SNPs) in the promoter region of the ADIPOQ gene. Two common SNPs were detected: rs17300539 and rs266729. Evidences of association between traits related to the metabolic syndrome and the SNPs were studied by implementing quantitative genetic association analysis. Results showed that SNP rs266729 was significantly associated with body weight (p-value=0.001), waist circumference (p-value=0.037), BMI (p-value=0.015) and percentage of total body fat (p-value=0.003). Up to 4.1% of heritability of obesity traits was explained by the rs266729 locus. Further cross-sectional analysis showed that carriers of the G allele had significantly higher values of waist circumference, BMI and percentage of total body fat (p-values 0.014, 0.004 and 0.032, respectively). No association was detected between SNP rs266729 and other clusters of metabolic syndrome or their traits except for HOMA-IR and fasting plasma insulin levels, p-values 0.035 and 0.004, respectively. In contrast, both measured genotype and cross-sectional analysis failed to detect an association between the SNP rs17300539 with traits and clusters of metabolic syndrome. In conclusion, we showed family-based evidence of association of SNP rs266729 at ADIPOQ gene with traits defining obesity in Arab population. This is important for future prediction and prevention of obesity in population where obesity is in an increasing trend.

Snoring and obstructive sleep apnea (OSA) are common disorders. Snoring associated with excessive daytime sleepiness is the most prevalent symptoms of OSA. Heart rate variability (HRV) is altered in patients with OSA and the degree of alteration may be linked to the severity of OSA. Alterations in HRV in 24 hour tachograms have recently been used in screening OSA patients. Autonomic components causing HRV can be reliably studied using spectral analysis techniques involving fast Fourier transformation (FFT). Twenty-three subjects, 13 with severe OSA and 10 controls matched for age and body mass index, were selected from patients who had undergone polysomnography (PSG) for snoring at Sultan Qaboos University Hospital, Oman. A 24- hour electrocardiogram (ECG) Holter recording was done at home, starting at 10am. Spectral analysis of ECG from sleep Holter and PSG recordings was analysed using fast Fourier transformation (FFT). The ECG RR intervals of snorers with OSA were significantly s...

To audit the sleep service at Sultan Qaboos University Hospital (SQUH), Muscat, Oman, and to explore deficiencies to introduce new measures of improvement. Polysomnography (PSG) reports and SQUH medical records of all patients who underwent sleep studies from January 1995 to December 2006 in the sleep laboratory at SQUH were reviewed and analyzed. Out of a total of 1042 sleep studies conducted in the specified period, 768 PSG recordings were valid for analysis. The audit showed that the Otolaryngology Department was the main referring specialty for PSG (43%). Snoring was the main symptom for 33% of the subjects referred, but suspicion of obstructive sleep apnea was the main reason for referral (38%). Three quarters of the patients were males who were also younger, and with lower body mass index compared to females (p=0.0001 for all). Despite large number of patients with an apnea-hypopnea index of >15 (n=261), only 94 (36%) patients received continuous positive airway pressure ti...

The aim of this research was to study the effects of overweight and leisure-time activities on maximal aerobic capacity (VO(2)max) in urban and rural Omani adolescents. A total of 529 (245 males, 284 females) adolescents, aged 15-16 years were randomly selected from segregated urban and rural schools. Maximal aerobic capacity was estimated using the multistage 20-meter shuttle-run test. The body mass index (BMI) of urban boys and girls was significantly higher than that of rural boys and girls. Urban boys and girls spent significantly less weekly hours on sports activities and significantly more weekly hours on TV/computer games than their rural counterpart. Urban boys and girls achieved significantly less VO(2)max than rural boys and girls (44.2 and 33.0 vs. 48.3 and 38.6 mL/kg/min, respectively). Maximal aerobic capacity was negatively correlated with BMI in urban boys. Overweight and inactivity had significant negative effects on cardiorespiratory fitness in urban boys and girls ...

Obstructive sleep apnoea/hypopnoea syndrome (OSAHS) is a disorder characterised by repetitive upper airway collapse during sleep in association with daytime sleepiness. It has an estimated prevalence of 2% and 4% among middle-aged women and men respectively. The aim of the study was to look at the association of body mass index (BMI), age and gender and prevalence of OSAHS in the Omani population. Polysomnography reports and hospital medical records of all patients who took part in the Sleep Study at the Sleep Laboratory of the Clinical Physiology Department, Sultan Qaboos University Hospital, between January 1995 and December 2006, were retrospectively reviewed. Data from both sources was gathered and analysed. A total of 1,042 sleep studies were conducted with 608 valid studies for analysis. The study showed that the apnoea/hypopnoea index (AHI) >15 was more prevalent in men compared to women (47.9% versus 33.5%, P = 0.001). There was significant correlation of AHI with BMI (P ...

The aim of this study was to screen Omani individuals for the familial aggregation of type 2 diabetes mellitus. A random cohort of 1182 Omani individuals visiting the Family Medicine Clinic at Sultan Qaboos University Hospital (SQUH), Muscat, Oman, for regular medical checkup, aged ≥40 years, were sampled. Patients were categorized into three groups: (1) individuals who claim not to have diabetes and had no family history of diabetes; (2) individuals who claim not to have diabetes but had family history of diabetes; (3) individuals with diabetes. Only 16% of these Omani individuals had no diabetes and no family history of diabetes. Another separate random cohort of 234 Omani type 2 diabetes mellitus patients, from the Diabetes Clinic at SQUH, were interviewed and questioned about their family history of type 2 diabetes mellitus. Ninety five percent of the patients had a family history of diabetes. Eighty percent had first degree relatives with diabetes and 46% had second degree rela...

The aim of this study was to estimate the prevalence of impaired fasting glucose (IFG) among Omani adults with no family history (FH) of diabetes and to investigate the factors behind the risk of developing type 2 diabetes (T2D), while excluding a FH of diabetes. A total of 1,182 Omani adults, aged ≥40 years, visited the Family Medicine & Community Health Clinic at Sultan Qaboos University Hospital, Oman, on days other than the Diabetes Clinic days, from July 2010 to July 2011. The subjects were interviewed and asked if they had T2D or a FH of T2D. Only 191 (16%) reported no personal history of T2D or FH of the disease. Of these, anthropometric and biochemical data was complete in 159 subjects. Of these a total of 42 (26%) had IFG according to the American Diabetes Association criteria. Body mass index, fasting insulin, haemoglobin A1C and blood pressure (BP), were significantly higher among individuals with IFG (P <0.01, P <0.05, P <0.01 and P <0.01, respectively). In a...

Lower mortality rates from coronary heart disease and higher levels of serum high-density lipoprotein cholesterol (HDL-C) have been observed in populations residing at high altitude. However, this effect has not been investigated in Arab populations, which exhibit considerable genetic homogeneity. We assessed the relationship between residing altitude and HDL-C in 2 genetically similar Omani Arab populations residing at different altitudes. The association between the levels of HDL-C and other metabolic parameters was also investigated. The levels of HDL-C were significantly higher in the high-altitude group compared with the low-altitude group. Stepwise regression analysis showed that altitude was the most significant factor affecting HDL-C, followed by gender, serum triglycerides, and finally the 2-hour postprandial plasma glucose. This finding is consistent with previously published studies from other populations and should be taken into consideration when comparing cardiovascula...

To determine the reference values of arterial stiffness indices, particularly augmentation index (AIx) and pulse wave velocity (PWV) using applanation tonometry in a healthy Omani Arab population. This prospective study was carried out in the Department of Clinical Physiology, Sultan Qaboos University Hospital, Muscat, Oman over a 2-year period from June 2011 to June 2013. The central AIx, aortic PWV (AoPWV), and central pulse pressure (CPP) were recorded from 120 healthy subjects recruited randomly from a normal population using a SphygmoCor device. The 2.5th and 97.5th percentiles were used to determine the reference ranges for men and women separately. Analyses were performed using univariate statistics. The mean age of the cohort was 38 years for men, and 35 years for women, with the ages ranging from 20-53 years. The overall mean central AIx was 13±11%, and for AoPWV was 6.7±1.6 m/s. The central AIx was higher in women (17 versus 10%; p<0.001), whereas the AoPWV was higher i...

Prevalence and heritability of metabolic syndrome (MetS) vary between populations according to the currently used criteria. We examined combinations for joint probabilities and heritabilities of MetS criteria from the National Cholesterol Education Program Adult Treatment Panel III (NCEP), World Health Organization (WHO), and International Diabetes Federation (IDF) in a sample of Omani families. We included 1277 subjects from 5 pedigrees. The likelihood ratio of diagnostic cluster dependence over clustering by chance was LDep = P(dependent)/P(independent). Heritabilities were adjusted by sex and age. The highest LDep were central obesity (CO) + high glucose level (HGl) + triglycerides (IDF, 3.08; NCEP, 4.38; WHO, 3.17; P < 0.001). Triglycerides combined with any other component were the most common cluster. The lowest LDep for IDF were high blood pressure (HBP) + CO + low HDL-C (1.21, P < 0.025); for NCEP were HBP + HGl + low HDL-C (1.21, P < 0.07). These components were gathered almost by chance alone. In contrast, the lowest LDep for WHO were HGl + CO + low HDL-C (2.01, P < 0.001). The WHO criteria yielded the highest heritability for a MetS diagnosis (h(2) = 0.9), followed by NCEP (0.48) and IDF (0.38). The rationale of the MetS diagnostics is based on insulin resistance. This base would be lost if we continue lowering cut-off points for diagnosis for increasing the sensitivity. The WHO showed the highest values for LDep for all components because they used the highest cut-off points.

The aim of this study was to investigate causes of the prevalence of the metabolic syndrome in multiparous Omani Arab women using the International Diabetes Federation definition (IDF). Of 392 married women (mean age 40 years), 354 (90%) were multiparous with an average parity of 8. They were divided into four parity groups: Para 0, Para 1-3, Para 4-6, and Para >6. Body mass index (BMI), waist circumference, fasting, and 2-hour glucose and insulin, plasma lipids, serum leptin, and homeostasis model assessment for insulin resistance (HOMA-IR) and blood pressure (BP) were measured. In the whole cohort, the IDF definition identified 28% women with the metabolic syndrome, whereas it identified 48% in Para >6. In comparison, the National Cholesterol Education Program (NCEP) definition identified 21% and 39%, respectively (kappa = 0.642). Waist circumference was positively associated with the number of live births (beta = 0.78, p = 0.0001). Compared to other individual IDF criteria, only age-adjusted large waist circumference carried the highest risk for having the metabolic syndrome in all groups (odds ratio [OR], 2.3, 95% confidence interval [CI], 1.0-5.4, 3.2, CI, 1.3-8 and 4.8, CI, 2.1-11.2). The high prevalence of the metabolic syndrome in multiparous Omani Arab women appeared to be influenced by the parity-related large waist circumference. The high dependency of the IDF criteria on waist circumference for the definition of the metabolic syndrome in this population has led to the misclassification of such women.

We performed a genome-wide scan in a homogeneous Arab population to identify genomic regions linked to blood pressure (BP) and its intermediate phenotypes during mental and physical stress tests. The Oman Family Study subjects (N = 1277) were recruited from five extended families of ~10 generations. Hemodynamic phenotypes were computed from beat-to-beat BP, electrocardiography and impedance cardiography. Multi-point linkage was performed for resting, mental (word conflict test, WCT) and cold pressor (CPT) stress and their reactivity scores (s), using variance components decomposition-based methods implemented in SOLAR. Genome-wide scans for BP phenotypes identified quantitative trait loci (QTLs) with significant evidence of linkage on chromosomes 1 and 12 for WCT-linked cardiac output (LOD = 3.1) and systolic BP (LOD = 3.5). Evidence for suggestive linkage for WCT was found on chromosomes 3, 17 and 1 for heart rate (LOD = 2.3), DBP (LOD = 2.4) and left ventricular ejection time (LVET), respectively. For △WCT, suggestive QTLs were detected for CO on chr11 (LOD = 2.5), LVET on chr3 (LOD = 2.0) and EDI on chr9 (LOD = 2.1). For CPT, suggestive QTLs for HR and LVET shared the same region on chr22 (LOD 2.3 and 2.8, respectively) and on chr9 (LOD = 2.3) for SBP, chr7 (LOD = 2.4) for SV and chr19 (LOD = 2.6) for CO. For △CPT, CO and TPR top signals were detected on chr15 and 10 (LOD; 2.40, 2.08) respectively. Mental stress revealed the largest number of significant and suggestive loci for normal BP reported to date. The study of BP and its intermediate phenotypes under mental and physical stress may help reveal the genes involved in the pathogenesis of essential hypertension.

To establish a suitable human model for the study of the genetics of complex diseases. We have selected an Omani Arab population to provide the statistical power required to study the genetics of complex diseases with confidence. This model consists of five multigenerational highly inbred pedigrees, descending from a small number of founders just a few generations ago with environmental homogeneity, restricted geographical distribution, detailed records and well-ascertained and -validated pedigrees. Stringent criteria were adopted for defining the phenotypes of hypertension, diabetes mellitus, dyslipidemias and obesity. The SOLAR genetic software package was used to draw the pedigree structure. Outstanding statistical power to detect susceptibility loci was obtained. This model represents a large homogeneous human family-based population for the study of genetic and environmental factors contributing to complex diseases.