Prevalence of Metabolic Syndrome in Newly Detected Type 2 Diabetes Mellitus

Biju Jacoba, Alvin Treasa Georgea, Antony T Pa, Regi Joseb, Shaliet Rose Sebastianb

a. Department of General Medicine, Amala Institute of Medical Sciences, Thrissur, Kerala, India; b. Department of Community Medicine, Sree Gokulam Medical College and Research Foundation, Thiruvananthapuram, Kerala, India*

Corresponding Author: Dr. Biju Jacob, Resident, Department of General Medicine, Amala Institute of Medical Sciences, Thrissur, Kerala, India. Phone: +91-9846127076, Email: drbijujacob@gmail.com

Abstract

Metabolic syndrome groups together insulin resistance, hyperinsulinemia, hyperglycemia, dyslipidemia, high blood pressure, and central obesity. This along with diabetes predisposes patients to cardiovascular disease and stroke. Socio-economic factors like sedentary lifestyle and eating habits are important causes for developing this syndrome. According to recent studies metabolic syndrome is increasing in our country and so an attempt was made to quantify the magnitude of the problem in our population. To find out the prevalence of metabolic syndrome among newly detected type 2 diabetes mellitus patients in central Kerala along with its association with age, gender, socio-economic class and also to compare male and female subgroups of metabolic syndrome. This was an observational study conducted during the time period between November 2011 and November 2012, comprising of 503 patients (297 men, 206 women) in the age group of 30-60 years with recently documented type2 diabetes (detected during the previous 6 months). Data was collected through pre-tested proforma and analyzed using Chi-square and Student’s t-test. The prevalence was found to be 66.2% according to the modified National Cholesterol Education Program Adult Treatment Panel 3 (NCEP ATP3) criteria for Asians and reduced to 52.7% on applying NCEP ATP 3 criteria. The prevalence was found to increase with age. Higher prevalence was noted in the female subgroup (p<0.05). Associations of metabolic syndrome were noted for systolic and diastolic hypertension, elevated triglycerides (more in men) low high-density lipoprotein (more in women) and waist circumference (p<0.05). Diabetes mellitus is increasing rampantly in our country due to genetic and environmental factors. Since there is a high association with metabolic syndrome as evidenced by this study, patients diagnosed should be screened for the same as the combination confers increased risk for cardiovascular disease and stroke.

Key words: Diabetes Mellitus, Metabolic Syndrome, Triglycerides, High-Density Lipoprotein

Introduction

Metabolic syndrome consists of a constellation of metabolic abnormalities such as insulin resistance, hyperinsulinemia, hyperglycemia, dyslipidemia, high blood pressure (BP), and central obesity which confer increased the risk to cardiovascular disease and diabetes mellitus. Type 2 diabetes mellitus when associated with the metabolic syndrome have increased the risk for coronary artery disease and stroke.1

At least 65% of patients having type 2 diabetes mellitus with associated metabolic syndrome die of some form of heart disease or stroke. It is very important to investigate a newly detected case of type 2 diabetes mellitus for signs of the metabolic syndrome so that complications can be prevented.2

Recent studies indicated that Kerala is the diabetic capital of India with a prevalence of 20% (compared to 8% national prevalence). Studies also show that the state’s cardiac mortality is the highest in country and 2 times of Japan and China.3 As the studies on diabetic patients with metabolic syndrome are few in Kerala, an attempt was made through this study to find out the prevalence of metabolic syndrome in newly detected cases of type 2 diabetes mellitus in central Kerala and to determine whether high living standards and sedentary life habits poses a real threat for metabolic syndrome.

Objectives

  1. To find the prevalence of metabolic syndrome in the age group of 30-65 years in all newly detected cases of type 2 diabetes mellitus (within 6 months) presenting in Out Patient and In Patient Departments of General Medicine at Amala Institute of Medical Sciences, Thrissur, Kerala.

  2. To find out the association of factors like age, gender, diet and lifestyle in the subgroup of people with metabolic syndrome.

Methods

This was an observational study comprising of 503 patients (297 men, 206 females) with recently documented Type 2 diabetes mellitus (within 6 months prior to the date of presentation), between 30 and 65 years who attended Out Patient and In Patient Departments of General Medicine at Amala Institute of Medical Sciences between November 2011 and November 2012. Diabetes mellitus was defined according to American, International and European Diabetes Association as – fasting blood sugar (FBS) > 126 mg/dl (fasting for at least 8 h) or 2 h postprandial sugar > 200 mg/dl (capillary and venous) or HbA1c > 6.5% or symptoms of diabetes + random blood sugar > 200 mg/dl. Patients with past history of stroke, coronary artery disease, and peripheral vascular disease were excluded from the study.1,2

Data were collected using pre-tested proforma formulated according to the Modified National Cholesterol Education Program Adult Treatment Panel 3 (NCEP ATP3) criteria for Asians (NCEP ATP3)* and other risk and associated factors. The patients were subjected to detailed clinical examination, including weight in kg, height in cm, body mass index (BMI) (weight in kg/height in m2). Body height was measured by stadiometer. Body weight was measured by using a digital scale. Waist circumference (WC) was measured midway between the inferior border of ribs and superior border of iliac crest (standing position). Hip circumference (HC) was taken around maximum circumference of buttocks (standing position). Patients were also looked for acanthosis nigricans and skin tags. Systolic BP (SBP) and diastolic BP (DBP) was measured twice at an interval of 3 min in sitting position after a rest of 15 min. Plasma glucose measured by glucose oxidase test. Serum uric was acid quantitated by uricase method. Total cholesterol estimated in fasting serum by using modified Roeshleu’s method. High-density lipoprotein cholesterol (HDL-C) in fasting serum sample quantitated by following the methodology of Burnstein et al. Triglyceride (TG) was estimated by enzymatic calorimetric test. Low-density lipoprotein cholesterol (LDL-C) calculated by using Friedwald equation. (LDL cholesterol = [Total Cholesterol]−[HDL-C) – [TG/5]) where all concentrations are in mg/dl. The factor TG/5 is an estimate of very LDL.

Vegetarian group was defined as patients who are strictly on vegetarian diet or consuming fish, meat, poultry <1 time/month. Mixed diet was defined as consuming fish at any frequency, but consuming other meats 1 time/month or total meat with red meat and poultry 1 time/month and, 1 time/week respectively. Non-vegetarians were defined as consuming red meat or poultry >1 time/month and the total of all meats > 1 time/week. Socio-economic status of each individual was recorded based on Kuppuswamy’s socio-economic scale. Lifestyle was divided into sedentary and non-sedentary based on an interview with the patient which included details of physical activity, job related and leisure time activities along with specific questions on exercise.

Statistical Analysis

The data were analyzed using IBM SPSS Version 20. Prevalence was expressed as proportions with 95% confidence interval (CI). Student’s t-test for interval data and Chi-square for nominal data as tests of significance. P<0.05 was regarded as significant.

Results

This study was conducted on 503 patients diagnosed with diabetes mellitus within 6 months. A modified NCEP ATP 3 criterion for Asians was used for diagnosing metabolic syndrome.

Prevalence of Metabolic Syndrome

Prevalence of metabolic syndrome among 503 study participants was found to be 66.20% (95% CI – 51.5-60). 59% of the study participants were males, and 41% were females. About 78.6% of females and 57.5% of males had metabolic syndrome. Occurrence of metabolic syndrome was more among Female diabetics. Crude odds ratio is 2.71 (95% CI – 1.81-4.067). Mean age of males was 49.13 and females was 50.03. Mean age of patients with metabolic syndrome was 49.76 and without metabolic syndrome was 49.16. Independent t-test showed no significant difference. Prevalence of metabolic syndrome was found to be highest in the age group of 46-55 years (67.4%). Chi-square test showed no significant difference between age groups (Table 1.)

Table 1. Factors associated with metabolic syndrome

thumblarge

All study participants were diabetics; irrespective of their blood glucose levels all were assumed to be positive for these diagnostic criteria. The mean value of FBS in the metabolic syndrome group was 178 mg/dl; post prandial blood sugar mean value was 250 mg/dl.

BP, HDL, TG, WC results are given in Table 1.

It is evident that out 239 participants, 87.9% with BP above 130/85 had metabolic syndrome. Odds ratio of 8.3 (95% CI – 5.25-13.11) indicates those with high BP had 8.3 times odds for developing metabolic syndrome compared to those with normal BP and it is statistically significant. Mean SBP among Patients with metabolic syndrome is 136.9 mmHg and mean diastolic BP was 84.2 mmHg. It is also found that the incidence of diastolic BP elevation is more compared to SBP in cases with metabolic syndrome (89.4% vs. 87.3%). Out of cases 142 cases with TG>150, 134 had metabolic syndrome (94.4%). The mean TG value is 151.3 mg/dl. In this study, 79.1% of the cases with the criteria for WC, WC > 90 cm for males and >80 cm for females had metabolic syndrome. In metabolic syndrome subgroup, mean values of WC is 91.6 cm and HC – 98.7 cm. On applying NCEP ATP3 criteria (WC > 102 cm in men and >88 cm in females) the prevalence of metabolic syndrome reduced statistically to 52.7% with 23.7% cases in males and 29% in females (Table 1) .

Life Style Factors

There was no statistical association observed with diet and 60.1% cases of predominant non-vegetarian diet had metabolic syndrome followed by 32.7% of the mixed diet and 7% in the vegetarian group. The study shows a high prevalence of metabolic syndrome in the nonalcoholic group. Considering physical activity, it was found that 70.3% in the sedentary group and 56.7% of non-sedentary group had metabolic syndrome. The poor had a high prevalence rate of 78%, followed by upper class (63%) and middle class (59%).

Body mass index (BMI) was used to classify obesity and 65.3% of the obese and 89% of the morbid obese cases were found to have metabolic syndrome and there was statistically significant association with metabolic syndrome in these groups. The mean BMI of metabolic syndrome sub group was 26. Regarding central obesity 89.7% of the patients had metabolic syndrome and it was statistically significant.

Waist-hip ratio > 9 (males) and > 8.5 (females) is seen commonly with metabolic syndrome but was not statistically significant. Uric acid >8 mg/dl is abnormal. Hyperuricemia has close association with metabolic syndrome but was not statistically significant.

Discussion

Asian Indians are a high-risk population with respect to diabetes and cardiovascular disease, and the numbers are consistently on the rise. The prevalence of metabolic syndrome in Indians vary according to the region, the extent of urbanization, lifestyle patterns, and socio-economic/cultural factors

This study demonstrates the prevalence of metabolic syndrome in newly detected Diabetic individuals to be 66.2% by Modified NCEP ATP3 criteria and 52.7% by NCEP ATP3 criteria. A similar study conducted by Linu Mohan et al in OP patients in Kerala in 2012 showed a prevalence of 38.5%.4 Another study in 2009 by Ethiraj Dhanaraj et al in diabetic North Indians observed a prevalence of 68%. In 2012, Thayyil et al observed 16.8% prevalence in Kerala’s police population.5 Studies in Mumbai in 2011 by Sawant et al observed the prevalence of 19.52% in general population.6 Studies conducted in Israel by Eytan Cohen et al showed the prevalence of only 10.6%7,8 and 34.3% in US population. This shows that type 2 diabetes mellitus significantly increases the risk for metabolic syndrome when compared to general population, but there was no significant difference in prevalence between the north and the south of India. Metabolic syndrome is rising in our society at an alarming rate owing probably to the sedentary lifestyle of Keralites. In the current study, it was found that among the cases of metabolic syndrome, 59.05% were males and 41% were females, but in the subgroup females were more affected (78.6.% vs. 57.6%). This was in contrast with the observations noted in studies conducted by Sawant et al (25% – males, 12.6 % – females) and Chow et al who observed higher prevalence in males. High prevalence in females may due to the sedentary lifestyle and unhealthy eating habits.

The study observed a significant increase in the metabolic syndrome with age. Maximum prevalence was seen in the age group of 46-55 years. Similar studies conducted by Linu Mohan et al showed higher prevalence of metabolic syndrome in middle-aged people. Studies by Sawant et al also shared similar observation with a marginal decrease after the age of 60.

In our study, it was clear that 87.9% of the people with metabolic syndrome had BP > 130/85 mmHg. It was also noted that incidence of DBP elevation was more compared to SBP (89.4% vs. 87.3%). Studies conducted by Linu Mohan et al also shared similar observation.

Low HDL in males and females were frequently seen with metabolic syndrome (89.5%). 94.4% of the metabolic syndrome cases also had hypertriglyceridemia. Studies conducted by Supriya et al, Linu Mohan et al supported the observation.9 Sawant et al also confirmed similar results, but found increased prevalence in men than women (64.2% vs. 33.8%). In this study, it was also found during gender comparisons that low HDL was significantly more in females than males. This might be because most cases in female group occur in menopausal age group and hence lack of estrogen and exercise may be causing low HDL.

WC of >90 cm for males and >80 cm for females was observed in 79.1% of the cases of metabolic syndrome which shows its high sensitivity in detecting the same. Studies conducted by Daliparthy Devi et al also showed sensitivity of 71% in males and 86% in females for detecting metabolic syndrome.10,11

This study showed that the prevalence of metabolic syndrome was the highest in the predominant nonvegetarians (60.2%) followed by mixed (32.1%) and vegetarian (7.2%) diet. Studies conducted by Nicco et al observed highest prevalence in predominant nonvegetarians (39.7%), followed by a semi-vegetarians (37.6%) and then vegetarians (25.2%).12

In the current study, prevalence of metabolic syndrome in alcoholics was not statistically significant (52.7%). This might be because the majority of the cases are light to moderate drinkers (Light – 5-15 g/day, Moderate – 15-30 g/day, Heavy – >30 g/day). Studies conducted by Thayyil et al observed significant association of alcoholism with metabolic syndrome (24.7% vs. 17.9%) Baiki and Shin C et al in Korea showed significant association of metabolic syndrome with heavy drinkers (63% increased risk compared with non-drinkers).13 This study shows no significant association between smoking and metabolic syndrome. This may be because of decrease in smokers among young population. Studies by Thayyil et al on the contrary showed increased prevalence of metabolic syndrome in smokers (15.2% vs. 9.6%) Sawant et al also showed similar findings. 59.8% of the cases of the sedentary group had metabolic syndrome which indicates significant association whereas Thayyil et al found that 16.6% of the cases of sedentary lifestyle were associated with metabolic syndrome. Obesity and morbid obesity were estimated based on BMI. It was seen that cases in these groups had a significant association with metabolic syndrome (57.7% and 85.4%). Other studies by Sawant et al also proves the high association of obesity with metabolic syndrome. Central obesity measured by waist/hip (W/H) ratio (>0.9 in males and 0.85 in females) is considered as an important marker of metabolic syndrome in the WHO criteria. In this study, statistically significant association (66.8%) was seen between W/H ratio and metabolic syndrome. Studies conducted by Vijay Kumar et al in central Kerala also shows a high prevalence of central obesity (85.6%).14 This could be attributed to the high living standards, unhealthy eating habits, and sedentary lifestyle of the Keralites.

In this study, it was also observed that if W/H ratio and BMI are both taken, they can diagnose more number of metabolic syndrome (89.7%) than each of them taken individually (BMI – 57.7%, W/H – 59.8%).

Even though the prevalence of hyperuricemia was low in the metabolic syndrome subgroup, those with high uric acid level had features of metabolic syndrome. Hyperuricemia is due to decreased excretion of uric acid due to hyperinsulinemia which causes increased proximal tubular sodium absorption. Increased fructose intake cause increased phosphorylation and breakdown in the liver with increased uric acid synthesis.15 Other similar studies by Etyah cohen et al in Israel showed hyperuricemia in 20% cases of metabolic syndrome.

In this study, high prevalence of metabolic syndrome was observed in the low socio-economic class, in contrast to other studies by Chetna Mangat et al in which high socio-economic class had greater prevalence of metabolic syndrome.16 This shows that lifestyle irrespective of social class has a direct effect on metabolic syndrome (for e.g. In this study, drivers were found to have a high prevalence of metabolic syndrome). High incidence in the poor may also be due to the lack of awareness and exercise in that group.

Conclusion

Diabetes significantly increases the risk for metabolic syndrome.

The prevalence of metabolic syndrome increases with age and more common in females. Both SBP and DBP were elevated in metabolic syndrome, but DBP elevation was more commonly seen. Low HDL-C and elevated TGs were seen to be associated with most cases of metabolic syndrome. Low HDL-C was seen more commonly in female, whereas hypertriglyceridemia was more common in men. Diabetic patients with obesity, morbid obesity, WC, and central obesity have a high association with metabolic syndrome. The current study shows no significant association of smoking and alcoholism with metabolic syndrome. Sedentary lifestyle definitely plays a very important role in development of metabolic syndrome.

End Note

Author Information

  1. Dr.Biju Jacob, MBBS, Resident, Department of General Medicine, Amala Institute of Medical Sciences, Thrissur, Kerala, India

  2. Dr.Alvin Treasa George, MBBS, MD, DNB, Associate Professor, Department of General Medicine, Amala Institute of Medical Sciences, Thrissur, Kerala, India

  3. Dr.Antony T P, MBBS, MD, MNAMS, MRCP, FRCP, Professor and Head, Department of General Medicine, Amala Institute of Medical Sciences, Thrissur, Kerala, India

  4. Dr.Regi Jose, MBBS, DPH MD, DNB, M Phil, Professor, Department of Community Medicine, Sree Gokulam Medical College and Research Foundation, Thiruvananthapuram, Kerala, India

  5. Shaliet Rose Sebastian, MBBS, Resident, Department of Community Medicine, Sree Gokulam Medical College and Research Foundation, Thiruvananthapuram, Kerala, India

Conflicts of Interest

None declared.

List of Abbreviations

  • NCEP ATP 3: National Cholesterol Education Program Adult Treatment Panel 3

  • BMI: Body mass index

  • HDL: High-density lipoprotein

  • TG: Triglycerides

  • WC: Waist circumference

  • FBS: Fasting blood sugar

Limitations

Gender equation was not balanced (predominant male population in the sample) Lack of quantification of smoking and alcohol intake.

* Modified National Cholesterol Education Program Adult Treatment Panel 3 (NCEP ATP 3) Criteria (Asians):

  1. Waist circumference: >90 cm – male, >80 cm – female

  2. SBP: >130 mmHg or DBP: >85 mmHg or previously diagnosed hypertension

  3. TG: >150 mg/dl

  4. HDL-C: <40 mg/dl – men, <50 mg/dl – women

  5. FBS > 110 mg.

Presence of >3 Criteria= Metabolic syndrome

References

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