Metabolic syndrome in hypertensive and non‐hypertensive subjects

Abstract Background and aims Hypertension is a major risk factor of cardiovascular diseases (CVDs), which attributes to one‐third of all deaths worldwide. It is also considered as a key feature of metabolic syndrome (MetS). The aim of the present study was to compare the presence of characteristic features of MetS in hypertensive and non‐hypertensive males and females and find out the percentages of MetS in hypertensive and non‐hypertensive adults. Methods This was a cross‐sectional study, involving 120 participants that included 60 hypertensives and 60 non‐hypertensives (35‐55 years). Data were obtained through an interviewer‐administered questionnaire. Fasting blood sugar (FBS) and lipid parameters [triglyceride‐(TG), high density lipoprotein (HDL)] were analyzed, and waist circumference (WC) was measured. Percentages of MetS among hypertensive and non‐hypertensive groups were determined according to both modified Adult Treatment Panel III (ATP III) and new International Diabetes Federation (IDF) criteria. Results were analyzed using SPSS version 21. Results Among the characteristic features of MetS, mean FBS and WC were significantly higher in hypertensive males compared with non‐hypertensive males (P < .001 and P = .002 respectively), while mean value of TG was significantly higher (P = .005) in hypertensive females compared with non‐hypertensive females. Further, the percentage of subjects in the total hypertensive group with increased FBS and increased WC was significantly higher than the non‐ hypertensive group. The percentage of subjects with MetS was significantly (P < .001) higher in hypertensive group (68%) compared with non‐hypertensive group (20%) according to modified ATP III criteria. When compared with new IDF criteria, it was 63% and 20%, respectively. Conclusion The percentage of subjects with increased FBS, WC, and MetS was significantly higher in the hypertensive group compared with non‐hypertensives group. These findings emphasize the urgent need to develop national strategies for early detection, and to take preventive measures to make people aware of the impact of metabolic syndrome.

detection, and to take preventive measures to make people aware of the impact of metabolic syndrome. Hypertension is not only a major risk factor of CVD that attributes to about one-third of all deaths worldwide but also considered as a key feature of MetS. Abdominal obesity and insulin resistance have been identified as the predominant underlying risk factors for MetS, while atherogenic dyslipidemia and hyperglycemia are considered as other common features of MetS. 4,5 Worldwide prevalence of MetS has increased significantly over the years. Studies have shown approximately 20% to 25% of the world's adult population have MetS and they are prone to have a threefold greater risk for CVD morbidity and fivefold greater risk of developing type 2 diabetes mellitus (T2DM). 6  Informed written consent was obtained from all the participants before the study. Hypertensive adults (diagnosed as hypertension >140/90 mmHg and/or on hypertensive drugs) were included in the "Test" group and non-hypertensive adults who were not diagnosed for hypertension and with normal blood pressure <120/80 mmHg, were included in "Control" group. Subjects who were pregnant, having severe diseases, physical impairments, and who did not like to participate in the study were excluded. The female and male distribution in each hypertensive and non-hypertensive group were similar (n = 30). Socioeconomic data, lifestyle information, and medical information were obtained through an interviewer-administered questionnaire.
For the analysis of FBS, 10 hours of overnight fast was considered, and for triglycerides and HDL cholesterol, 12 hours of overnight fast was considered. FBS analysis was done using Biorex diagnostics, glucose kit where FBS <100 mg/dL was considered as normal. For lipid profile, separated serum was analyzed using Stanbio cholesterol LiquiColor kit, where TG < 150 mg/dL, HDL > 40 mg/dL (for males) and > 50 mg/dL (for female) were considered as normal. WC < 90 cm for South Asian males and <80 cm for South Asian females were considered normal. 13,14 Blood pressure was measured using a mercury sphygmomanometer by a qualified medical professional following All five components were taken into account in this study. 15,16

| Statistical analysis
Data were analyzed using statistical package for social sciences (SPSS) version 21. Significance of mean differences of MetS related characteristics between hypertensive and non-hypertensive groups was done using independent sample t-test. For Means ± SD and frequencies, descriptive analysis was done. Fisher's exact test (two-tailed) was used to determine the significance of association between two categorical variables (continuous variables were categorized according to cutoff values). P value was used to measure the significance. If P < .05, the observed difference or association was considered as significant.

| RESULTS
The mean age of total, male, and female subjects were 47.6±6.2, 47.03±6.4, and 48.35±6.15 years, respectively. The mean age of hypertensive subjects (50.13±4.9 years) was significantly higher (P < .001) than non-hypertensives (45.25±6.6 years). Medical information and lifestyle information of the study subjects are presented in Table 1. There were no significant differences encountered with regard to the physical inactivity, diet control, occupation, familial hypertension, familial diabetes, familial heart disease, and familial dyslipidemia between hypertensive and non-hypertensive subjects.
Mean values of assessed biochemical parameters are presented in Table 2. both hypertensive males and females had a higher mean FBS compared with non-hypertensive subjects where a significantly (P < .001) higher FBS was observed only in male hypertensive subjects compared with non-hypertensive males. Mean TG was significantly (P = .005) higher in hypertensive females compared with nonhypertensive females. The mean WC was higher than the normal reference level in both hypertensive females and non-hypertensive females, but the value was significantly (P = .002) higher in hypertensive males compared with non-hypertensive males.
The presence of MetS in this study population was assessed using modified ATP III and new IDF criteria, and the data are given in Table 3 Table 4. The percentage of subjects with increased FBS was significantly (P = .025) higher in the total hypertensive group and hypertensive males compared with respective non-hypertensive groups ( Table 4). The majority of the females in hypertensive (90%) and non-hypertensive groups (77%) had increased WC. The percentage of subjects with decreased HDL than normal reference level was significantly (P = .002) higher in hypertensive males than non-hypertensive males, while a significant difference between female hypertensives and non-hypertensives was not observed. The percentage of subjects with increased FBS, WC, TG were significantly higher in MetS subjects than non-MetS individuals.  19,20 Further, in the present study, significantly higher FBS level was observed in hypertensive males and a higher percentage of hypertensive subjects had elevated FBS. Several studies have found a close association between obesity and hypertension. 21,22 Central obesity shows a strong association with hypertension compared with other parameters that assess obesity. 23,24 Central obesity, which is depicted by increased WC, is considered as one of the main underlying factors and one of the main features of MetS. 13 Hence, central obesity can be used as an early predictor of MetS. In the present study, WC was used to measure central obesity.

T A B L E 1 Medical information and lifestyle information of the study subjects
WC was significantly higher in the male hypertensive group, while mean WC was higher than the risk cutoff value in both hypertensive and non-hypertensive females. Increased WC in these normotensive subjects is alarming and suggests the need for routine monitoring to prevent the onset of MetS with time.
According to a report of ATP III, MetS is associated with elevated triglycerides. 25 Although only female hypertensive group had a significantly higher mean triglyceride level, the increased TG and decreased HDL observed in non-hypertensive subjects indicate the need for random screening and education about the subsequent effects of the altered lipid profile and anthropometric effects that may lead to onset of MetS. The major drawback of our study was limiting the study setting to one location, which is categorized as an urban area in Sri Lanka. Data collection was done by four researchers, hence bias in reporting is a possibility. Inability to recall all facts by the participants with regard to lifestyle and medical information was an additional drawback.
In summary, the percentage of subjects with increased FBS, WC, and MetS was significantly higher in the hypertensive group compared with the non-hypertensive group.
Hence, the findings of the present study not only indicate that hypertensive subjects are more prone to have MetS but also emphasize the urgent need to develop national strategies for the early detection and preventive measures to make people aware of the metabolic syndrome.
ACKNOWLEDGMENT All participants of the study

CONFLICT OF INTEREST
The authors declare that they have no conflict of interests. Lohini Athiththan had full access to all of the data in this study and takes complete responsibility for the integrity of the data and the accuracy of the data analysis.

TRANSPARENCY STATEMENT
Lohini Athiththan affirms that this manuscript is an honest, accurate, and transparent account of the study that is being reported; and no important aspects of the study have been omitted; and that any discrepancies from the study as planned (and, if relevant, registered) have been explained.

ETHICS STATEMENT
Approval for the present work was obtained from the Ethics review committee of Faculty of Medical Sciences, University of Sri Lanka, Sri Lanka (reference numbers-MLS 06/2015, B Pharm 05/2015).

DATA AVAILABILITY STATEMENT
The authors confirm that all data supporting the findings of this study are available within the article [and/or] its supplementary materials.