Diagnostic performance of waist-to-height ratio in identifying cardiovascular risk factors and metabolic syndrome among adult Saudis. A cross-sectional study

Objectives: To evaluate the diagnostic performance of waist to height ratio (WHtR) to screen for cardiovascular risk factors (CVRF) and metabolic syndrome (MetS) among Saudis. Methods: Between June 2013 and August 2014, a cross-sectional study of 3,063 adult Saudis of both genders from King Khalid Hospital, Riyadh, Saudi Arabia was conducted. Using the “WHO STEPwise Surveillance-Instrument V2.1”, which uses sequential steps including questionnaires and anthropometric and biochemical measurements of MetS and CVRF. Waist to height ratio validity in defining central obesity, MetS, and CVRF were tested using receiver operating characteristic curve (ROC), sensitivity, specificity, positive and negative predictive values, and accuracy. Using multivariate regression analyses for adjustment of confounders as age and gender were applied to compute adjusted odds ratios (aOR). Results: The diagnostic potential of WHtR was excellent for central obesity (area under the curve [AUC] = 0.98), and MetS (AUCs = 0.86); it was good for CVRF ≥2 (AUCs = 0.79) and was satisfactory for dyslipidemia (AUCs = 0.66). The sensitivities and negative predictive values exceeded 85% for diagnosing central obesity, diabetes, and hypertension. Adjusted odds ratios for age and gender showed that WHtR ≥0.50 significantly increased the risk of diabetes, hypertension, and ≥2 CVRF by almost 4-fold, and increased the risk of dyslipidemia by 2-fold. Conclusion: Waist height ratio showed a good diagnostic performance for CVRF and MetS among Saudis. Furthermore, WHtR ≥0.5 increased the risk of dyslipidemia, diabetes mellitus and hypertension

Atomic-scale characterization of single and double layers of InAs and InAlAs Stranski-Krastanov quantum dots

We report a detailed structural characterization of single and double layers of InAs and InAlAs quantum dots (QDs) and their wetting layers (WLs) by atomic force microscopy (AFM) and cross-sectional scanning tunneling microscopy (X-STM). The X-STM analysis with atomic resolution showed that the InAlAs WL consists of two distinct layers: a bottom part where all the Al atoms of the InAlAs alloy settled, and a top part containing exclusively In and Ga atoms. The QDs formed from the InAlAs layer contains no Al atoms at all and lie on top of the Al-rich WL. In the double layers of QDs, the InAlAs QDs were used as a seed to influence the nucleation of the InAs QDs grown on top. A gradual decrease in the density of the top InAs QDs was observed in the AFM images with increasing thickness of the GaAs spacer. The X-STM images showed that both QDs layers were completely intermixed for a 2-nm-thick spacer, while effective strain-induced stacking of both types of QDs was observed for a GaAs spacer thickness of 4 nm. However, both QD layers were completely decoupled for a GaAs spacer thickness of 8 nm and could thus be treated as individual layers

Influence of the InAs Coverage on the Performance of Submonolayer-Quantum-Dot Infrared Photodetectors Grown with a (2×4) Surface Reconstruction

Two infrared photodetectors based on submonolayer quantum dots, having a different InAs coverage of 35% and 50%, were grown, processed and tested. The detector with the larger coverage yielded a specific detectivity of 1.13×10 11 cm Hz 1/2 W -1 at 12K, which is among the highest values reported in the literature for that kind of device

Characteristics of out-of-hospital cardiac arrest patients in Riyadh province, Saudi Arabia: a cross-sectional study

IntroductionLittle work has been done on out-of-hospital cardiac arrest (OHCA) in Saudi Arabia. Our goal is to report the characteristics of OHCA patients and predictors of bystander cardiopulmonary resuscitation (CPR).Materials and methodsThis cross-sectional study utilized data from the Saudi Red Crescent Authority (SRCA), a governmental emergency medical service (EMS). A standardized data collection form based on the “Utstein-style” guidelines was developed. Data were retrieved from the electronic patient care reports that SRCA providers fill out for every case. OHCA cases that were attended by SRCA in Riyadh province between June 1st, 2020 and May 31st, 2021 were included. Multivariate regression analysis was performed to assess independent predictors of bystander CPR.ResultsA total of 1,023 OHCA cases were included. The mean age was 57.2 (±22.6). 95.7% (979/1,023) of cases were adults and 65.2% (667/1,023) were males. Home was the most common location of OHCA [784/1,011 (77.5%)]. The initial recorded rhythm was shockable in 131/742 (17.7%). The EMS mean response time was 15.9 min (±11.1). Bystander CPR was performed in 130/1,023 (12.7%) and was more commonly performed in children as compared to adults [12/44 (27.3%) vs. 118/979 (12.1%), p = 0.003]. Independent predictors of bystander CPR were being a child (OR = 3.26, 95% CI [1.21–8.82], p = 0.02) and having OHCA in a healthcare institution (OR = 6.35, 95% CI [2.15–18.72], p = 0.001).ConclusionOur study reported the characteristics of OHCA cases in Saudi Arabia using EMS data. We observed young age at presentation, low rates of bystander CPR, and long response time. These characteristics are distinctly different from other countries and call for urgent attention to OHCA care in Saudi Arabia. Lastly, being a child and having OHCA in a healthcare institution were found to be independent predictors of bystander CPR

Non-Communicable Disease Risk Factors among Employees and Their Families of a Saudi University: An Epidemiological Study

Objectives:To assess the prevalence of non-communicable disease (NCD) risk factors among Saudi university employees and their families; to estimate the cardiovascular risk (CVR) amongst the study population in the following 10years. Methods:The NCD risk factors prevalence was estimated using a cross-sectional approach for a sample of employees and their families aged ≥ 18 years old, in a Saudi university (Riyadh in Kingdom of Saudi Arabia; KSA). WHO STEPwise standardized tools were used to estimate NCD risk factors and the Framingham Coronary Heart Risk Score calculator was used to calculate the CVR. Results:Five thousand and two hundred subjects were invited, of whom 4,500 participated in the study, providing a response rate of 87%. The mean age of participants was 39.3±13.4 years. The majority of participants reported low fruit/vegetables consumption (88%), and physically inactive (77%). More than two thirds of the cohort was found to be either overweight or obese (72%), where 36% were obese, and 59% had abdominal obesity. Of the total cohort, 22–37% were found to suffer from dyslipidaemia, 22% either diabetes or hypertension, with rather low reported current tobacco use (12%). One quarter of participants was estimated to have >10% risk to develop cardiovascular disease within the following 10-years. Conclusion:The prevalence of NCD risk factors was found to be substantially high among the university employees and their families in this study

Socio-demographic characteristics of participants by nationality (n = 4,500).

<p>Socio-demographic characteristics of participants by nationality (n = 4,500).</p

Prevalence of the clinical NCD risk factors, the clustering of NCD risk factors and 10-year cardiovascular risk scores by nationality and gender (n = 4500).

<p>Prevalence of the clinical NCD risk factors, the clustering of NCD risk factors and 10-year cardiovascular risk scores by nationality and gender (n = 4500).</p