|Year : 2017 | Volume
| Issue : 1 | Page : 19-22
Prevalence of metabolic syndrome in hypothyroidism: Experience in a tertiary center in South India
Jaideep Khare1, Smitha Nalla1, Jyoti Wadhwa1, Prachi Srivastava2, Babul Reddy1, Prasun Deb1
1 Department of Endocrinology, Krishna Institute of Medical Sciences, Secunderabad, Telangana, India
2 Department of Dermatology, Krishna Institute of Medical Sciences, Secunderabad, Telangana, India
|Date of Web Publication||19-Dec-2016|
Department of Endocrinology, Krishna Institute of Medical Sciences, Secunderabad - 500 003, Telangana
Source of Support: None, Conflict of Interest: None
Introduction: Thyroid disorders are among the most common endocrine disorders, with an overall prevalence of hypothyroidism about 10.95% in the general population. Prevalence of the metabolic syndrome (MetS) in the Indian population is about 31.6%, with the prevalence of 22.9% in men and 39.9% in women. Aim: The aim of this study is to determine the prevalence of MetS and its components in people with hypothyroidism. Materials and Methods: A total of 154 hypothyroid patients attending our outpatient department were consecutively enrolled for the study. MetS identified by National Cholesterol Education Program's Adult Treatment Panel III report (ATP III). Clinical data were obtained by interviewing the patients and referring to their case folders and prescriptions. The anthropometric indices were recorded. The laboratory parameters that were analyzed included fasting lipid profile, thyroid function tests, and fasting blood sugars. Results: The patients were aged between 18 and 75 years, with a mean age of 43.6 years, and the female-to-male ratio was 123:31. The overall prevalence of the MetS was 53.24% by ATP III criteria, which is significantly higher than that in the general population, as reported earlier in various studies. The most common occurring MetS-defining criterion was increased waist circumference, and hypertension was the least documented criterion. Conclusion: MetS occurs in approximately every second patient of hypothyroidism, and so, routine screening for components of MetS may be of benefit in this group.
Keywords: Adult Treatment Panel III criteria, hypothyroidism, metabolic syndrome
|How to cite this article:|
Khare J, Nalla S, Wadhwa J, Srivastava P, Reddy B, Deb P. Prevalence of metabolic syndrome in hypothyroidism: Experience in a tertiary center in South India. CHRISMED J Health Res 2017;4:19-22
|How to cite this URL:|
Khare J, Nalla S, Wadhwa J, Srivastava P, Reddy B, Deb P. Prevalence of metabolic syndrome in hypothyroidism: Experience in a tertiary center in South India. CHRISMED J Health Res [serial online] 2017 [cited 2020 Jun 1];4:19-22. Available from: http://www.cjhr.org/text.asp?2017/4/1/19/196035
| Introduction|| |
Thyroid disorders are among the most common endocrine disorders, with an overall prevalence of hypothyroidism about 10.95% in the general population. 
Hypothyroidism is often associated with increased cardiovascular morbidity, but the mechanisms for this are unclear, for which various theories have been proposed. One of the proposed theories is the causal association with the metabolic syndrome (MetS). Hence, our aim of the study was to find the prevalence of MetS in hypothyroid patients.
The National Cholesterol Education Program's Adult Treatment Panel III report (ATP III)  has identified the MetS as a multiplex risk factor for cardiovascular disease that is deserving of greater clinical attention.
The overall prevalence of the MetS in the Indian population is about 31.6%, with the prevalence of 22.9% in men and 39.9% in women. 
| Materials and methods|| |
This was a cross-sectional observational study carried out at the Endocrinology Department.
A total of 154 patients known to have hypothyroidism were recruited consecutively for the study. The inclusion criteria for enrollment into the study included the following: (1) adult patients with previously diagnosed hypothyroidism on treatment, and (2) willing to participate in the study. Exclusion criteria included (1) very sick patients; (2) transient hypothyroidism like drug-induced hypothyroidism, and pregnancy; and (3) not willing for participation in study. The patients who met the inclusion criteria were included and history pertaining to hypothyroidism, management modalities and the presence of comorbidities which included diabetes mellitus and hypertension was taken.
Clinical examination included body mass indices obtained from the formula weight/height 2 (kg/m 2 ). The waist circumference (WC) was measured at a point midway between the iliac crest and the lower rib. The presence of goiter and acanthosis nigricans was noted.
The laboratory parameters that were assessed included fasting blood glucose and fasting lipid parameters (total cholesterol [TC], high-density lipoprotein cholesterol [HDL-C], low-density lipoprotein cholesterol [LDL-C], and triglycerides TG]).
Patient who were previously diagnosed with hypothyroidism who were on replacement therapy, and those who were incidentally diagnosed as having hypothyroidism (thyroid stimulating hormone [TSH] levels > 4.5 mIU/L and/or low T4 or low T3 levels) were included in our study and were evaluated for presence of MetS or it is component features.
The presence of the MetS was determined using the ATP III criteria. The presence of three or more of any of the followings: WC ≥102 cm in men and ≥88 cm in women; serum TG level ≥150 mg/dL; HDL-C ≤40 mg/dL in men and ≤50 mg/dL in women; blood pressure ≥130/85 mmHg (or previously diagnosed hypertensive on antihypertensive therapy); and fasting serum glucose ≥110 mg/dL (or previously diagnosed diabetic on antidiabetic therapy).
| Results|| |
The ratio of females to males was 123:31 (n = 154). The mean age was 43.6 years, 41.9 years in females and 50.3 years in males with no significant difference. A summary of baseline characteristics is shown in [Table 1] and components of MetS in [Table 2].
The mean TC, TG, LDL-C, and HDL-C levels in males were 182 mg/dL, 141 mg/dL, 93 mg/dL, 34 mg/dL and females were 167 mg/dL, 138 mg/dL, 87 mg/dL, and 41 mg/dL, respectively. Elevated TG (>150 mg/dL) was found in 15 (48.3%) males and 59 (47.9%) females. Low HDL-C (≤40 mg/dL in men and ≤50 mg/dL in women) was found in 15 (48.3%) male and 63 (51.2%) female.
The mean WC in male and female was 110.7 and 105.18, respectively. Increased WC was found in 17 (54.8%) male and 79 (64.2%) female.
Dysglycemia was found in 7 (22.5%) male and 39 (31.7%) female with an overall prevalence of 29.87%. Hypertension was found in 7 (22.5%) male and 31 (25.2%) female with an overall prevalence of 24.67%.
MetS with three or more component was found in 18 (58.06%) male and 64 (52.03%) females with overall prevalence of 53.24%.
Increased WC was the most commonly occurring MetS defining criterion and it was documented in 62.34% of the patients. The distribution of the components of the MetS according to ATP III criteria in the study patients are shown in [Table 2]. Acanthosis nigricans was noted in 6 (19.3%) male and 31 (25.2%) female. Goiter was noted in 5 (16.1%) male and 24 (19.5%) female.
| Discussion|| |
Hypothyroidism is often associated with increased cardiovascular morbidity, but the mechanisms that increase this risk are unclear. Various mechanisms have been proposed to be potentially responsible for it and the MetS is one of these. Hence, our aim of the study was to find the prevalence of MetS in hypothyroid patients.
In a study by Gupta et al. in 2004,  the prevalence of the MetS in the Indian population was about 31.6%, (22.9% in men and 39.9% in women). Prevalence of individual components of the MetS in men and women, respectively, were as follows: central obesity (WC; men >102 cm, women >88 cm) 25.6% and 44.0%; low HDL cholesterol (men <40 mg/dL, women <50 mg/dL) 54.9% and 90.2%; high TGs (≥150 mg/dL) 32.3% and 28.6%; and impaired fasting glucose or diabetes in 16.9% and 16.1%. The prevalence of physical inactivity, hypertension, hypercholesterolemia, and high LDL-C was greater in the MetS group in both men and women. 
Chow et al., in 2008  reported a prevalence of MetS of 26.9% in males and 18.4% in females in Southern India. Deepa et al., in 2007  (Chennai Urban Rural Epidemiology Study 34 study), noted a prevalence of MetS of 18.3%.
Thus, the prevalence of MetS and its component was significantly higher in our study group of hypothyroid patients than in the general population, as reported in the above studies. Not much-published literature exists regarding the prevalence of MetS in hypothyroid patient, but a report from Nigeria found the prevalence of MetS in hypothyroid patients being as high as 40%. 
In hypothyroidism, common lipid abnormalities include hypercholesterolemia and elevated LDL-C levels, but HDL-C levels may be normal or even elevated in severe hypothyroidism.  In this study, the mean levels of TG and TC were high and mean HDL-C was low. The mean LDL was within normal limits.
Hypertension findings in our patient cohort were similar to those reported by Saito et al.,  who described significantly higher prevalence of hypertension in hypothyroid patient (15.8%) in comparison with euthyroid subjects (5.5%).
In this study, hypothyroid patients had a high prevalence of hypertension (24.67%). The possible pathophysiological mechanisms responsible for this include changes in circulating catecholamines, their receptors, and abnormalities in the renin-angiotensin-aldosterone system. 
Our study cohort had higher levels of individual criteria for diagnosing MetS, as well as MetS as a whole, as compared to the general population, described in the previous publications. Similar findings were reported by a Korean study,  which found a relationship between abnormal thyroid function and individual MetS components such as BP, TC, TG, HDL-C and fasting glucose, and also showed that higher levels of TSH may predict MetS in that population.
As reported earlier central obesity has a role in the development of the MetS and sometimes precedes the appearance of other MetS components.  In this study as well, the most common component of MetS was increased WC; suggesting that patient who are not having MetS at present are at higher risk for developing the same in the future if not intervened.
| Conclusion|| |
The overall prevalence rate of the MetS in our study was much higher than the rates reported in the general population in various studies and comparable to studies of hypothyroid patients.
Routine screening for MetS component in hypothyroid patient may unmask the MetS, which may help in early intervention.
We would like to acknowledge Dr. Jalaj Khare, for helping in statistical analysis and to K. Apoorva and M. Krushika Reddy for helping with data collection.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Table 1], [Table 2]