Metabolic syndrome among adults in Qatar: A review of the literature across medical specialties

This study aims to collate all metabolic syndrome-related studies among adults in Qatar, shedding light on gaps in knowledge related to this topic to be addressed in future research studies. PubMed was used in searching for metabolic syndrome-related articles in Qatar, which was executed using relevant terms and was conducted with no restrictions. A second search was executed at a later stage to include any recent publications. A total of 20 articles were found to be relevant and related to the topic in hand. Three definitions of metabolic syndrome were used across the reviewed studies, which were classified based on medical specialties. The main findings and key components of each study were summarized. Studies were unevenly distributed across various medical specialties. This article serves to direct future research activities by identifying what aspects of the disease have been covered under current or past research projects and what more needs to be addressed comprehensively in view of clinical and public health significance.


INTRODUCTION
Obesity, hypertension, dyslipidemia, and insulin resistance are collectively known as metabolic syndrome. 1 Numerous studies have reported that an increased morbidity and mortality is associated with metabolic syndrome. 1 -3 The number of metabolic syndrome cases continue to increase in developing countries, 4 to the point where some name it "the new epidemic." 5 A recent systematic review reported a high prevalence rate of metabolic syndrome in the Middle East. 6 Qatar has witnessed substantial growth on many of its sectors, leading to an increase in gross domestic product. 7 Along with the growth came a rise of lifestyle-related diseases due to the adoption of an unhealthy lifestyle, 8 including the rise of metabolic syndrome figures among the population in Qatar. 8 A meta-analysis of cross-sectional studies in the Middle East reported that the prevalence of metabolic syndrome in Qatar ranges between 26% and 33%. 6 Al-Thani et al., in accordance to the results of a national health survey, reported that 28% of the Qatari population fulfills the criteria for metabolic syndrome based on the International Diabetes Federation (IDF) criteria. 9,10 An earlier study by Musallam et al. in 2008 had reported prevalence rates of 26.4% and 34 % in the Adult Treatment Panel III (ATP III) criteria 11 and the IDF criteria, respectively. 12 This paper aims to collate all published studies on metabolic syndrome among adults in Qatar, providing information on past research projects to identify areas for future research studies.

Search details
PubMed was used in searching for metabolic syndrome-related articles in Qatar. The search was conducted on April 23, 2019, and repeated on November 15, 2019, without restrictions of any type. The following term was used during the search: "metabolic syndrome AND Qatar." This review excluded articles on the following: a pediatric population, dissertations or thesis, pooled analysis, or reviews of any type. Data from each study was extracted into a table designed for the purpose of this article.

Reviewed studies
Considering the size and magnitude of the disease, we found insufficient research involving metabolic syndrome among adults in Qatar. The first search conducted in April returned 54 articles. The second search in November returned an additional 10. A total of 20 articles were identified as relevant and retrieved. Majority of the articles were crosssectional (75%), cohort (15%), case control (5%), and experiments (5%). Studies were unevenly distributed across various medical specialties, mental health, public health, andrology, cardiology, nutrition, and others. For easy access for future researchers, the studies were presented per specialty. Table 1 summarizes all 20 studies that were included in this article.

Epidemiology
Qatar's general population shows that prevalence appears to cluster around 26% and 34% using ATP III and IDF criteria, respectively. 12,13 In 2010, Bener et al. reported on the gender-and age-related differences among metabolic syndrome patients. The study found that the prevalence of metabolic syndrome was highest among the age group of 30 -39 years and 40 -49 years among males and females, respectively. 14 In 2012, Ismail screened 136 patients in primary health care centers, reporting a metabolic syndrome prevalence rate of 46.3% among obese patients. The most commonly encountered factors were increased blood pressure and waist circumference, while being diabetic and increasing age were significantly found to increase the risk of metabolic syndrome. The findings of this study cannot be generalized to the remaining population due to its small sample size and all patients being in the primary health care center. 15 In 2016, Al-Thani et al. reported a 28% prevalence rate for metabolic syndrome among 2496 Qatari citizens, identifying waist circumference ($ 102 cm and $94 cm for men and women, respectively) as the best predictor for the presence of other metabolic syndrome-related factors. 9

Public health
In 2013, Bener et al. attempted to identify the optimum cutoff values for various possible potential predictors of metabolic syndrome in Qatar, finding that waist circumferences of 99.5 cm and 91 cm for men and women, respectively, are better predictors of metabolic syndrome in Qatar. 16 Later in 2014, they highlighted the role of family history of metabolic syndrome in type 2 diabetes mellitus in Qatar, reporting a significantly (P ¼ 0.009) higher proportion of metabolic syndrome patients with a positive family history of type 2 diabetes mellitus (46.7%) than without type 2 diabetes mellitus (33.8%). 17 In relation to lifestyle patterns and metabolic syndrome, Al-Thani et al. recruited a sample of Qatari women and found that a high-risk lifestyle pattern and metabolic syndrome are associated. 18 Another related study found an inverse relationship between adhering to the Qatar dietary guidelines and metabolic syndrome in a sample of 1109 people in the Qatari population, further reporting that 83% of the sample did not meet the recommendations for dietary intake, including vegetables, fruits, legumes, high fiber, and whole grains; 70% was classified as obese or overweight; 50%-72% were reported to frequently consume sweetened beverages/sweets; and 47% consumed fast food frequently. 19 Under lifestyle management, Hammoudeh et al. conducted a clinical trial investigating the role of nonexercise activity thermogenesis (NEAT) on metabolic syndrome. A total of 200 participants were tested to find out whether increasing one's energy expenditure affects the components of metabolic syndrome. The study found no difference between the groups that followed NEAT and those who did not. 20

Mental health
One study reported a higher prevalence of metabolic syndrome among schizophrenia patients than the general population (36.5% vs. 18.7%, P , 0.001). Schizophrenia patients were found to have twice the risk of developing metabolic syndrome in the sample. Central obesity was the most commonly encountered factor when compared to the general population. 21 In addition to obesity, high blood pressure was found to be among the factors that contribute the most to the increased prevalence in a sample of patients with mental disorders, although no difference in the prevalence of metabolic syndrome was reported when compared to the general population. 22 Another study investigated the sleeping patterns of mentally ill patients, regardless of their treatment, and found that they have extended sleep hours compared to healthy controls, which was further intensified by the use of antipsychotics. The study also found that being a female with central obesity was significantly associated with longer sleep duration. 23

Heart disease
Al-Aqeedi et al., reported on the prevalence (69.4%) of metabolic syndrome among male patients with acute coronary syndrome (ACS) and without a history of diabetes. They found that common components among this population are decreased HDL (94.1%), increased fasting blood glucose (89.8%), increased triglycerides (81.8%), and increased waist circumference (61.7%). 24 Nutrition In relation to vitamin D, Al-Dabhani et al., studied the prevalence of vitamin D deficiency and its relationship with metabolic syndrome. They found that approximately 64% of the 1205 participants in this study were vitamin D-deficient, with a slightly increased number of vitamin D-deficient men (69%) than women (61%). Those with metabolic syndrome had 8% lower serum vitamin D than those without (P ¼ 0.01). A significantly positive association was found for vitamin D deficiency with waist circumference, HDL, and high triglyceride levels. 25 Ganji et al., continued this line of work, demonstrating an inverse relationship between the prevalence of metabolic syndrome and the concentrations of serum 25hydroxyvitmain D (25(OH)D) among Qatari women aged 20 to 80 years old, with obesity being the primary driver for metabolic syndrome and low levels of vitamin D. 26 Another group of researchers investigated the relationship between vitamin D and metabolic syndrome in relation to hearing loss among diabetes patients. The study reported a significant association between vitamin D deficiency and metabolic syndrome on the one hand and hearing loss on the other hand in diabetes patients, as approximately 25% of the study sample reported hearing loss. 27

Urology and andrology
Canguven et al. investigated the relationship between vitamin D treatment and metabolic syndrome, sexual hormones, and erectile dysfunction and found that treating vitamin D-deficient middle-aged men with egocalciferol (vitamin D2) significantly improved testosterone levels and erectile function (P , 0.001). The mean body mass index (BMI) was significantly decreased (P ¼ 0.001), along with hemoglobin A1c (HbA1c) (P ¼ 0.001), LDL (P ¼ 0.001), and triglycerides (P ¼ 0.035). No changes in luteinizing hormone (LH) levels were noted, whereas the prostate-specific antigen (PSA) values were significantly increased (P , 0.001). 28 Another study by Canguven et al., investigated the relationship between metabolic syndrome and testosterone therapy, showing that testosterone treatment improved components of metabolic syndrome and diabetes control with no adverse effects. Testosterone treatment was associated with a significant decrease in BMI (P , 0.0001) and total cholesterol (P , 0.0001) and triglyceride (P ¼ 0.016) levels and an increase in HbA1c (P , 0.0001) level. 29 Obstetrics Al-Hail et al., studied creatine kinase (CK) and metabolic syndrome features among women with and without polycystic ovarian syndrome and found that CK, independent of the polycystic ovarian syndrome phenotype, is associated with an increase in BMI and waist circumference (.80 cm) and with two or more features of the metabolic syndrome. 30

DISCUSSION
The article in hand gathered and summarized the literature involving metabolic syndrome in Qatar and was published on PubMed. The current literature on metabolic syndrome in Qatar seems to be clustered under a handful number of specialties or topics, wherein other areas seem to lack studies involving metabolic syndrome and therefore could create an opportunity for future possible research. The majority of articles were public health/epidemiology related, with a scattered number of articles falling under other medical specialties. More diverse and specialized research under other specialties is required, needed, and encouraged to ascertain the extent of the disease and other disease-related aspects and to aid in formulating possible potential and effective strategies in the prevention of such metabolic syndrome. Furthermore, regarding the discussion, this is basically taken from the highlights of each of the studies included in the review. Following the order is not usually a requirement, as we wanted to cover those matters from a population level first and then an individual level. Metabolic syndrome is a pandemic that continues to burden societies, 31,32 including the Qatari society as illustrated in the increasing number of metabolic syndrome cases, the prevalence of which ranged from 26% to 34%, 12,13 with highest rates reported among those aged 30 to 39 years among males and 40 to 49 years among females. 14 Interventions targeting the various components of the syndrome are needed 4 with specific focus on these age groups. Lifestyle changes are among those that have been cited as beneficial. 33 In an international panel recommendation, physical activity and several lifestyle habits were highlighted as prevention methods. 34 In the reviewed articles, Al-Thani et al., have shown that the majority of Qatari adults do not meet the recommendations for certain dietary intake. 19 Together with Bener et al., 18 they flagged the need to investigate the social and cultural factors influencing the dietary habits in Qatar and highlighted the need for culturally sensitive interventions at the population and individual levels. 18 Raising awareness comes at the front of these efforts and can be implemented and inflammatory markers other than with CRP, did not allow access to muscle biopsy tissue) IDF through campaigns targeting the negative consequences of the disease along with the possible preventive measures that can be taken. 12 Given the widespread prevalence of vitamin D deficiency in Qatar, recommendations for vitamin D supplementation and fortifying staple foods with vitamin D were given. 25 Screening for type 2 diabetes mellitus among metabolic syndrome patients 17 and the use of testosterone therapy to reverse metabolic syndrome and improve glycemic control in hypogonadal men 28 were among the recommended interventions in the reviewed articles.

CONCLUSION
This article serves as a road map for future research work involving metabolic syndrome in Qatar by providing an overview of what has been done under each medical specialty, if any. Building on the identified gaps, this review highlights the need for a more detailed and comprehensive approach in future research (including both observational and experimental research studies at a larger population scale) involving metabolic syndrome and its related aspects.