Prevalence of metabolic syndrome and the association with sociodemographic characteristics in adult population of Banja Luka

Background/Aim. Metabolic syndrome (MS) is a cluster of metabolic and hemodynamic disorders that increase the risk of developing atherosclerotic cardiovascular diseases and type 2 diabetes mellitus. The aim of this study was to determine the prevalence of MS and its components in adult population of Banja Luka and association with sociodemographic characteristics. Methods. A total of 685 participants (348 men and 337 women), aged 18 years and over, were analyzed. The diagnosis of the MS was based on definition set by the International Diabetes Federation (IDF). Results. The prevalence of the MS was high (37.5%), slightly higher in women (38.3%) than in men (36.8%), but without statistically significant difference (p = 0.686). Prevalence of each individual component of the MS in the study group was over 30% (systolic blood pressure ≥ 130 mmHg – 42.0%; diastolic blood pressure ≥ 85 mmHg – 31.0%; triglycerides ≥ 1.7 mmol/L – 36.1%; high density lipoprotein (HDL) cholesterol ˂ 1.03 for men and ˂1.29 for women – 31.2%; glucose ≥ 5.6 mmol/L – 32.8%; central obesity ≥ 94 cm male and ≥ 80 cm female – 62.6%). The prevalence of the MS was not associated with gender, but with age. A number of participants increased with incresed age in the group with the MS with statistically significant difference compared to the group without the MS. The study showed an association between level of education and the MS. Low level of education was associated with the appearance of the MS with statistically significant differences (df = 3; p = 0.013). Association between level of education and the MS was shown in women (df = 3; p = 0.000), but not in men (df = 3; p = 0.883). Retirees and housewives were significantly present in the group with the MS, students and unemployed in the group without the MS, while employed participants showed no statistically significant difference. Conclusion: The MS was diagnosed in over one-third of adults in Banja Luka. Prevalence of MS was not associated with gender, but it was associated with age, level of education as well as with some categories of employment.

32.8%; central obesity ≥ 94 cm male and ≥ 80 cm female -62.6%).The prevalence of the MS was not associated with gender, but with age.A number of participants increased with incresed age in the group with the MS with statistically significant difference compared to the group without the MS.The study showed an association between level of education and the MS.Low level of education was associated with the appearance of the MS with statistically significant differences (df = 3; p = 0.013).Association between level of education and the MS was shown in women (df = 3; p = 0.000), but not in men (df = 3; p = 0.883).Retirees and housewives were significantly present in the group with the MS, students and unemployed in the group without the MS, while employed participants showed no statistically significant difference.Conclusion: The MS was diagnosed in over one-third of adults in Banja Luka.Prevalence of MS was not associated with gender, but it was associated with age, level of education as well as with some categories of employment.

Introduction
Metabolic syndrome (MS) is a collection of cardiometabolic abnormalities that represent a risk for type 2 diabetes, coronary heart disease and other cardiovascular diseases 1 .The World Health Organization (WHO) in 1998 proposed a definition of the MS on the basis of previous studies 2 .WHO definition put diabetes or impaired fasting glycaemia or impaired glucose tolerance or insulin resistance as a mandatory criterion for the MS.Besides, a person must have 2 more following risk factors: diagnosed hypertension (≥ 140/90 mmHg), dyslipidemia (elevated triglycerides ≥ 1.7 mmol/L or low level of high density cholesterol (HDL) cholesterol -for male < 0.9 mmol/L and for female < 1.0 mmol/L, obesity determined by body mass index ≥ 30 kg/m² or waist/hip ratio > 0.9 (male) or > 0.85 (female) and microalbuminuria (≥ 20 µg/min).It was pointed out that this was only a framework of definitions and that there was the need to work on its improvement.
Today there are more definitions used in research which makes it difficult to compare results.There are definitions in use which do not set any component as a condition for assessing the presence of the MS.These are the Third Report of the National Cholesterol Education Program (NCEP) Expect Panel on Detection, Evaluation and Treatment of High Blood Cholesterol in Adults (Adult Treatment Panal III -ATP III) and that of the National Heart, Lung, and Blood Institute (NHLBI).According to these definitions, presence of 3 components represent the MS, but using different limits for individual components.For example, according to the ATP III definition 3 the MS exists when 3 or more of the following factors are fulfilled: 1. central obesity: waist circumference > 102 cm (male) or > 88 cm (female); 2. triglyceridemia (≥ 1.7 mmol/L); 3. low HDL cholesterol: < 1.0 mmol/L (male) and < 1.3 (female); 4. blood pressure ≥ 135/85 mmHg or medication; 5. fasting plasma glucose ≥ 6.1 mmol/L.
One of recent definition is the definition of the International Diabetes Federation (IDF) 4 .IDF definition made abdominal obesity a mandatory criterion with cut-points for waist circumference based on gender and ethnicity, for Europian men ≥ 94 cm and women ≥ 80 cm.According to the IDF definition, diagnosis of the MS is based on the presence of abdominal obesity plus any 2 out of 4 risk factors.
Several associations (IDF Task Force on Epidemiology and Prevention, NHLBI, American Heart Association, World Heart Federation, International Atherosclerosis Society and International Association for the Study of Obesity) continued to debate criteria for diagnosis of the MS and in 2009 a harmonized definition was released [Joint Interim Statement (JIS) definition].JIS definition excludes abdominal obesity as a mandatory risk factor while making the presence of any 3 out of 5 risk factors (waist circumference ≥ 94 cm -male and ≥ 80 cm -female; triglyceridemia ≥ 1.7 mmol/L or medication; low HDL cholesterol < 1.0 mmol/L -male and < 1.3female or medication; blood pressure ≥ 130/85 mmHg or medication; fasting plasma glucose ≥ 5.6 mmol/L or diabetes mellitus diagnosis) neccessary for diagnosis of the MS 5 .
In addition to the parameters that are included in the definitions as the MS risk factors, the influence of lifestyle and sociodemographic factors on the occurrence of the MS should be investigated.
The aim of this study was to determine the prevalence of the individual components of the MS as well as association with socio-demographic factors in adult population of Banja Luka.

Methods
A population-based cross-sectional survey was conducted in 2012 on adult population of Banja Luka, registered in the Family Medicine at the Health Center.According to the Report of the Health Care Fund of the Republic of Srpska, at the time of the study, the Health Center had 175,000 registered citizens.The target group in this study was 18 years of age and over.There were 142,000 registered citizens of the appropriate age.In relation to that number, a representative sample of 700 respondents was formed.
The survey instrument was the questionnaire containing: personal data of the patient, age, gender, education, employment status, the results of 3 consecutive measurements of blood pressure, waist size, and laboratory analyses (fasting glycemia and lipids).
All participants were devided into 4 groups according to their level of education (no schooling, incomplete primary or primary education, secondary school, post-secondary and university education).
The interviews were conducted by 103 family medicine teams.The second and third measurements of blood pressure were averaged and this value was used for further analysis.For each patient, the presence of the MS was determined by using the IDF definition.According to this definition, a person has the MS if, in addition to abdominal obesity, has 2 more of the following risk factors: blood pressure ≥ 130/85 Petrović V, et al.Vojnosanit Pregl 2018; 75(5): 447-452.mmHg or already diagnosed hypertension; triglycerides ≥ 1.7 mmol/L; HDL cholesterol ˂ 1.03 mmol/L for men (M) and ˂ 1.29 mmol/L for women (F) or previously treated this lipid disorders; morning fasting glycemia ≥ 5.6 mmol/L or already diagnosed diabetes 4 .At the end of the study, we obtained 685 properly filled out questionnaires from which the data was entered into the database in the SPSS computer program.The response rate was 97.85%.
Data analysis was done using descriptive statistical methods.The significance of differences between groups, or different categories of respondents, was calculated by using the Pearson's χ² test.The results are presented in tables.
The research was conducted in accordance with the Declaration of Helsinki as revised in 2013.Before entering the research each participant gave written informed consent.

Results
This study included 685 participants aged 18 years and more, 348 (50.8%) men and 337 (49.2%) women.The representation of women and men was approximately the same (Table 1).The mean age of respondents was 48.77 ± 17.888 years, for women 50.40 ± 18.964 and men 47.20 ± 16.657.The mean age of subjects with the MS (55.87 ± 15.762) was higher than of those without the MS (44.51 ± 17.751).Most of the respondents were employed -285 (41.7%), and the second most represented were retired persons -180 (26.4%).By level of education most of them had secondary school -392 (58.1%) (Table 1).The prevalence of the MS in the population registered at the Health Center Banja Luka, according to the IDF definition, was 37.5%.The prevalence was slightly higher in women than in men, but without statistically significant difference (Table 1).
It has been shown that the occurrence of the MS in the study group did not correlate with gender, but did correlate with age.With increasing age, the occurrence of the MS was higher in the group of patients with the MS with a statistically significant difference compared to the group without the MS (Table 1).In the group of patients with the MS, prevalence increased with age and reached a maximum in the group of 60-69 years (24.9%),followed by the group aged 50-59 years (23.7%).
By employment status, in the study group, the largest group were the employed patients (41.7%).There were no statistically significant differences in the representation of the employed and self-employed in the groups with and without the MS (Table 1).As a special form of employment status, retirees and housewives were singled out and they were significantly over-represented in the group with the MS compared to the group without the MS, while students and unemployed were significantly more frequent in the group without the MS.
Our study showed association between level of education and the MS (Table 1).The low level of education was associated with the appearance of the MS with statistically significant differences (df = 3; p = 0.013).The association between level of education and the MS was shown in women (df = 3; p = 0.000), but not in men (df = 3; p = 0.883).Women with out schooling and incomplete or finished primary education were significantly over-represented in the group with the MS, and women with post-secondary and university education in the group without the MS.
The risk factors included in the IDF definition (Table 2) were highly represented in the total study group, each with more than 30%.The most common risk factors were central obesity (62.6%) and systolic blood pressure (42.7%), accompanied by other risk factors that were more frequently statistically significant in the group with the MS compared to the group without the MS.

Discussion
The prevalence of the MS in the adult citizens of Banja Luka registered at the Health Center is high.More than onethird of the adult population has the MS that is in accordance with recently published study in the Republic of Srpska 6 .Research conducted in Croatia, in a family medicine setting, showed even higher prevalance of 45% 7 .According to a meta-analysis by Kastorini et al. 8 , the MS occurrence in the world according to the IDF definition ranges from about 7.4% to about 50%.In Western countries, the prevalence of the MS according to the IDF definition is lower comparing to the results of our research, ranging from 20% to 30% (for example in Spain, 24.3%) 9 .
The varying definitions make some study comparisons more difficult.By a certain definition of the NCEP ATP III, the MS prevalence in the US population older than 20 years was 33% during the period from 2003 to 2012 10 .The same definition of the MS used in the Iranian urban population showed a very high prevalence of 42.3% 11 .
There was no statistically significant difference in the MS prevalence between women and men in our study.Results of studies around the world related to the prevalence of the MS by gender are different.Al-Daghri et al. 11 showed that women in Saudi Arabia had a significantly greater prevalence of the MS than men (47.2% to 40.3%, respectively) according to the ATP III definition,.The mentioned American study 10 showed that the prevalence of the MS is significantly higher in women than in men (35.6% v.s.30.3%, p < 0.001).Another US study evaluating the occurrence of the MS of 5,227 adult African-Americans, also showed greater occurrence of the MS in women (40%) than in men (27%), according to the NCEP ATP III 12 .
There is a positive association between the MS and age.Representation of patients in the group with the MS increased with age from 7.0% in the group aged 18 to 29 years to 24.9% in the group of 60 to 69 years old, and over the age 70 there was a slight decrease in prevalence.Brazilian LATINMETS study 13 also confirmed the association between the MS prevalence and age, especially over the age of 40 years.Almost all researchers in the world who have addressed this issue confirmed the occurrence of the MS in association with age 1, 14-16 .It turned out that among the employed participants, there were no statistically significant difference in the occurrence of the MS, while the unemployed were significantly less represented in the group with the MS (8.6% to 17.8%; p = 0.001; p < 0.05).Research conducted in Saudi Arabia showed a statistically significant lower incidence of the MS among the unemployed in comparison to all other work categories 11 .For our respondents, we singled out two groups -retirees and housewives who had a high presence of the MS.Both are highly statistically more frequent in the group with the MS.

Petrović
Our study confirmed the association between the MS prevalence and the level of education.Respondents without education and with incomplete primary and finished primary education were significantly more common in the group with the MS than in the group without the MS, which is in accordance with most studies in the world.Research on the adult Saudi population was accompanied by the emergence of the MS through 3 levels of education: school up to 6 years, 7-12 years of school and more than 12 years of school, and the significantly lower incidence of the MS was confirmed in those who had more than 12 years of education compared to the other two groups 11 .A recent study conducted in China including 15,477 urban population adult subjects age 18-74 years showed that higher education is associated with a higher prevalence of the MS in men, but lower among women 16 which is in accordance with our results.In the present study, men with post-secondary and university education were more frequently represented in the group with the MS than in the group without the MS but without statistically significant difference, while women with post-secondary and university education were represented statistically significantly lower in the group with the MS.Khan et al. 12 showed that the low level of education in African-American women was associated with the emergence of the MS, but not in African-American men.
Prevalence of each individual component of the MS in our study group was over 30%.Among the factors contributing to the MS, the most prevalent was central obesity (62.6%), followed by elevated systolic blood pressure (42.7%), elevated triglycerides (36.1%), elevated blood glucose (32.8%) and low HDL (31.2%).Our results are similar to the results of the study from the North-East China that reported similar results 16 .The results of the great Europiean project MORGAN, investigating the MS in 10 European countries, showed that the individual factors of the MS were dependent upon the age of the subjects.The most prevalent factor in young women was obesity, in older women blood pressure, whereas in men of all ages elevated blood pressure was the dominating factor 1 .

Conclusion
The prevalence of the MS was detected in over onethird of the adult residents in Banja Luka, while prevalence of each individual component of the MS in the study group was over 30%.The most common risk factors were central obesity followed by blood pressure.The prevalence of the MS was not associated with gender but with age.
The association between level of education and the MS was confirmed in women, but not in men.