Metabolic Syndrome among Adults in Jordan: Prevalence, Trend, and Associated Factors

Background: Metabolic Syndrome is emerging as a global health challenge in the 21 st century. Multiple epidemiological studies were conducted among variety of ethnic groups showed discrepancies in the prevalence of both Metabolic Syndrome and its individual components. The aims of this study were to determine the prevalence of Metabolic Syndrome in Jordan using the ATP III and IDF criteria and assess the changes of Metabolic Syndrome prevalence over time. Methods: Data from the 2017 cardiovascular risk factors national survey were. The survey collected extensive data from a national population-based sample of Jordanian residents. A structured questionnaire was used to collect sociodemographic variables and clinical data. Blood samples were taken for biochemical measurements. Anthropometric characteristics were measured by the same team of trained eld researchers. A total sample of 4,056 aged between 18 and 90 years were included. The ndings from the 2017 survey were compared with the ndings of the 2009 survey that adopted the same methods and procedures. Results: The crude prevalence of Metabolic Syndrome was 48.2% (52.9% among men and 46.2% among women; p<0.001) according to IDF criteria. Using the ATP III criteria, the prevalence was 44.1% (51.4% among men and 41% among women, p<0.001). The age standardized prevalence rate of Metabolic Syndrome was 44% (95% CI: 42.7%, 45.4%) and 39.9% (95% CI: 39.6%, 41.2%) using the IDF denition and ATP III criteria, respectively. The kappa measure of agreement showed excellent agreement between the two denitions (k= 81.9%, p<0.001). Of all participants, 41.7% met both the IDF and ATP III diagnostic criteria, 6.6% met the IDF criteria only and 2.5% met the ATP III criteria only. The age-standardized prevalence rate of Metabolic Syndrome was signicantly higher in 2017 (45.7% in men and 44.5% in women) than that in 2009 (34.6% in men and 39.8% in women). Conclusion:


Background
Non-communicable diseases (NCDs) are emerging as a global health concern with more remarkable increasing trend in low and middle income countries (1). The Global Burden of Diseases reports have shown that metabolic abnormalities are the most important determinants of NCDs all over the world (2).
Each metabolic abnormality has its harmful effect but a combination of multiple abnormalities might produce what is known as Metabolic Syndrome (2,3). Metabolic Syndrome more strongly predicts cardiovascular diseases and increases the risk of developing diabetes mellitus and chronic kidney disease than its individual components do (3,4). There is an escalating concern regarding Metabolic Syndrome in the past few years due to multiple factors such as epidemiologic transition, life-style changes and burden of nutrition disorders, yet confusion regarding Metabolic Syndrome still exists due to a lack of a uni ed de nition; debate about its etiology and pathogenesis and lack of a consensus protocol for its treatment contribute to this uncertainty (2,3,(5)(6)(7). The International Federation for Diabetes (IDF) demonstrated a standard de nition in 2006 for Metabolic Syndrome as "a cluster of the most dangerous heart attack and cardiovascular diseases risk factors" (3). This de nition addresses both clinical and research needs, and provides suitable and accessible tools for diagnosing Metabolic Syndrome status.
Prevalence of Metabolic Syndrome has been increasing worldwide for several decades especially in developing countries (8). It is still hard to provide accurate evaluation of Metabolic Syndrome prevalence due to a variety of de nitions used, for instance, the prevalence ranges from 10-84% in worldwide across different countries, ethnic groups, gender and age. Multiple epidemiological studies were conducted among variety of ethnic groups showed discrepancies in the prevalence of both Metabolic Syndrome and its individual components (9,10).
The importance of studying the prevalence and trend of Metabolic Syndrome stems from the fact that it could potentially be used as an adequate index for detecting people at high risk for NCDs and other cardiovascular diseases (2). The aims of this study were to determine the prevalence of Metabolic Syndrome in Jordan using the Adult Treatment Panel III (ATP III) and IDF criteria and assess the changes of Metabolic Syndrome prevalence over time.

Study design and sampling
This survey was conducted among Jordanian adults over a period of four months in the year 2017. The survey methods and procedures were described and detailed in other publications (11,12) and they were similar to those that had been used in the 2009 survey (13). A multistage cluster sampling approach with probability proportional to size random selection method was used to ensure adequate coverage of the entire target population. A city/village was selected from each of the 12 governorates of Jordan. The sample of households was chosen in two stages. In the rst stage, well-de ned geopolitical areas (clusters) were selected from each city/village. At least one cluster was selected from each city/village at random using computer-generated random numbers. The second stage of household selection involved choosing a random sample of households from a list of households in a selected area. The households from each cluster were selected at random using a systematic sampling technique. A team of two (a female and a male) visited and invited selected households to report to the health center in that site, fasting in a given day after explaining the study for them. Subjects were asked not to take their medications during that day and to bring them along with them to the health center. Subjects aged ≥ 18 years were eligible for inclusion in the study. To encourage participation, the team worked on weekends and holidays and provided free transport for those who asked for it. The overall response rate was 78.1%. The study was approved by the Ethical Committee at the National Center for Diabetes, Endocrinology, and Genetics, Amman, Jordan. An informed consent was obtained from each participant.
Data were treated with strict con dentiality and used only for scienti c purposes.

Data collection
Trained interviewers administered a comprehensive structured questionnaire speci cally prepared for the purpose of the study. Main data obtained included sociodemographic variables, diabetes and other cardiovascular disease risk factors. Blood pressure was measured in a standardized way by trained researchers as explained in the 2009 survey (13). Three blood samples were drawn from a cannula inserted into the antecubital vein and used for the different laboratory measurements. Tubes containing sodium uoride potassium oxalate were used for glucose measurement. Samples were centrifuged within 1 hour at the survey site and transferred by separate labeled tubes in ice boxes to the central laboratory of the National Center of Diabetes, Endocrinology, and Genetics in Amman, Jordan. All biochemical measurements were carried out by the same team of laboratory technicians using the same method throughout the study period. Fasting plasma glucose and lipid measurements were performed according to the manufacturers' instructions, using COBAS autoanalyzer (Roche Diagnostics, Basel, Switzerland).

Anthropometric measurements
Weight was measured, while subjects were minimally clothed and not wearing shoes using digital scales (seca). Height was measured using a portable stadiometer (SECA 214 portable stadiometer). Body mass index (BMI) was calculated as weight in kilograms divided by height in meters squared (14). Waist circumference (WC) was measured at the midway between the iliac crest and the lower rib margin, over light clothing, using un-stretchable tape (seca 203), without any pressure to body surface. Waist to hip ratio (WHR) was calculated as WC divided by hip circumference and waist to height (WHtR) was calculated as WC divided by height in centimeters. All measurements were taken by the same team of well-trained persons using the same tools.

De nitions
Being overweight or obese were classi ed as proposed by WHO for diagnosing overweight (BMI of 25-29.9 kg/m 2 ) and obesity (BMI of 30 kg/m 2 or more) in adults (15). Metabolic syndrome was de ned according to IDF criteria and ATP III diagnostic criteria. Diabetes was de ned according to IDF Diabetes Atlas 8th edition diagnostic criteria (16).

Statistical Analysis
Data were entered and analyzed using the Statistical Package for Social Sciences software "SPSS IBM version 24". The raw data le for 2009 were re-analyzed using the same variable de nitions to assess the time-trends in Metabolic Syndrome prevalence. Proportions were used to estimate the prevalence of Metabolic Syndrome. Overall and age-speci c prevalence rates were obtained and reported separately for each gender. We derived age-standardized prevalence rates in order to permit comparison between the different surveys and with studies in other countries, using the world population as a standard population. Chi-square was used to compare proportions. Multivariate binary logistic regression was conducted to determine factors associated with metabolic Syndrome. A p-value of less than 0.05 was considered to be statistically signi cant.

Socio-demographic characteristics
This study included 4056 participants [1193 (29.4%) men and 2863 (70.6%) women] aged 18 years or more. About 26.5% of them were between 40-49 years old. Men were signi cantly older than women; the mean (SD) age was 47.5 (14.6) year for men and 42.2 (13.7) year for women (p < 0.001). The majority of participants (94%) were Jordanians while 6% were Syrians. Table 1 shows the socio-demographic characteristics of participants according to gender.

Anthropometric and Clinical Characteristics
The mean anthropometric and biochemical characteristics for Jordanians are shown in Table 2. There was a signi cant difference in the majority of studied parameters. The mean (SD) of BMI was 29.5 (6.0) kg/m², being signi cantly higher in women than in men (30 (6.4) kg/m² vs. 28.4 (4.8) kg/m²; p < 0.001).
The mean systolic and diastolic blood pressure, mean fasting blood glucose and mean triglyceride were signi cantly higher in men than in women. On the other hand, women have signi cantly higher cholesterol, HDL and LDL level than men.  Tables 3 and 4 show the crude and age-standardized sex-speci c prevalence rates of Metabolic Syndrome and its individual components using the ATP III and IDF criteria.  Age-speci c prevalence rate of Metabolic Syndrome The age-speci c prevalence of Metabolic Syndrome for men and women is shown in Fig. 1 and Fig. 2 using IDF de nition and ATP III de nition, respectively. In both de nitions, the prevalence of Metabolic Syndrome increased signi cantly with age in both men and women (P < 0.001). With the IDF de nition, the prevalence rose from 13.1% from men aged 18-29 years to 66.9% for those aged 60-69 years and then declined to 60.6% in those aged 70 years and above. While the prevalence rose from 11.7% in women aged 18-29 years to 81% in women aged 70 years and above.
With the ATP III de nition, the prevalence rose from 10.5% for men aged 18-29 years to 73.4% for those aged 60-69 years and then declined to 56.4% in those aged 70 years and above. While the prevalence rose from 8% in women aged 18-29 years to 77.4% in women aged 70 years and above.
Prevalence of metabolic syndrome according to sociodemographic characteristics Tables 5 and 6 show the prevalence of metabolic syndrome according to socio-demographic characteristics using the IDF and ATP III criteria, respectively.
Among components of metabolic syndrome, abdominal obesity was the most prevalent metabolic abnormality. According to the IDF de nition, women had higher prevalence of abdominal obesity (77.8%) compared to men (67.3%) (p < 0.001). Low HDL cholesterol was the second most common metabolic abnormality in both men and women. Elevated Triglycerides and low HDL level prevalence rates were 41.8% and 59.1%, respectively. The difference between men and women was statistically signi cant in elevated triglycerides level (p < 0.001) but not in low HDL level (p = 0.057). High fasting blood sugar prevalence rates were 37.5% and 28.8% using the IDF and ATP III de nitions. Men had signi cantly higher prevalence of high fasting blood sugar using both IDF and ATP III de nitions (47.4% and 40% respectively) compared to women (33.4% and 24.2% respectively). The relative frequencies of the number of metabolic abnormalities according to the IDF and ATP III measurements are shown in Fig. 3 and Fig. 4.

Changes in the metabolic syndrome rate between 2009 and 2017
The 2017 sample had a higher mean age compared to the 2009 sample (43.8 (14.2) year and 41.8 (13.3) years, respectively). Table 7

Discussion
This study reports the prevalence of Metabolic Syndrome and its individual components among adults in Jordan using the IDF and ATP III de nitions and compares the ndings with the ndings of a previous study conducted with the same methodology in 2009.
When the IDF diagnostic criteria was used, the age-standardized prevalence rates of Metabolic Syndrome in Jordan was 44% (45.7% in men and 44.5% in women). This rate is slightly higher than what had been reported in the US population (40%) (17), and much higher than that in the Australian population (29.1%) (10), the European population (from 10 to 30%) (10), and the Iranian people (37.4%) (18). Compared to Arab countries, the age standardized prevalence of Metabolic Syndrome was higher than the prevalence reported a prevalence of 39.3% (19,35). In addition, a study in Emirates reported a prevalence of 50.3% in 2012 which is markedly higher than Jordan's prevalence (24), but another study in 2008 revealed a prevalence of 39.6% which is approximately similar to the rate found in this study (25). The considerable discrepancy in the prevalence of Metabolic Syndrome among and across different nations and populations could be a result of the integration of genetics, environmental aspects and factors, epidemiological transition, and differences in life-style. Differences in the de nition used and differences in the sampling approaches and procedures might explain some of the variations in the prevalence rates (23,24,25 Women had a signi cantly higher crude and age-standardized prevalence rate of obesity and central obesity using both the IDF and ATP III. The explanation of the large waist circumferences and body mass index in women could be due to genetic and/or hormonal differences, the large number of births and the fact that women in Jordan are less likely to participate in physical activity due to cultural and social limitations ( 47).
When we compared these ndings to a previous study conducted in 2009 in Jordan with the same methodology and Metabolic Syndrome de nition (using the IDF diagnostic criteria), we found that the age-standardized prevalence of Metabolic Syndrome in this current study was markedly higher compared to 2009 study. Also, the age-adjusted prevalence rates of abdominal obesity and hyperglycemia in this present population were higher than that in 2009 population. On the other hand, lower age-standardized prevalence for low HDL level was seen in 2017 survey compared to the 2009 study. These variations in the prevalence, could be explained by shifting from traditional dietary habits (diet rich in bers, vegetables, fruits and cereals) into consuming more animal products and junk food, with high amounts of carbohydrates and saturated fats (13).

Conclusions
The prevalence of Metabolic Syndrome in Jordan is considerably high and increasing. With the IDF diagnostic criteria, many factors were associated with Metabolic Syndrome including gender, age, occupation, region, and marital status. This escalation in Metabolic Syndrome prevalence is assumed to be as a result of life-style changes and epidemiological transition, unhealthy dietary habits, and lack of exercise. Therefore, healthy lifestyle programs encouraging appropriate dietary habits and physical activity are strongly recommended in Jordan. Once the diagnosis is made, the potential treatment should be proactive and persistent in its goal of reducing the risk of CVD and type 2 diabetes. Age-speci c prevalence of Metabolic Syndrome using the ATP III de nition in Jordan The relative frequencies of the number of metabolic abnormalities according to IDF de nition