International Journal of Clinical Biochemistry and Research

Print ISSN: 2394-6369

Online ISSN: 2394-6377

CODEN : IJCBK6

International Journal of Clinical Biochemistry and Research (IJCBR) open access, peer-reviewed quarterly journal publishing since 2014 and is published under auspices of the  Innovative Education and Scientific Research Foundation (IESRF), aim to uplift researchers, scholars, academicians, and professionals in all academic and scientific disciplines. IESRF is dedicated to the transfer of technology and research by publishing more...


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Pangajam P and Juliette A: Association between thyroid hormones & lipid profile in type 2 diabetes mellitus patients- A case control study in tertiary care hospital


Introduction

Diabetes mellitus and thyroid dysfunction are the most common endocrinological disorders in the current era. Type 2 Diabetes mellitus is one of the most important global health issue as it affects more than 463 million people and it is expected to reach around 700 million by 2045.1 Type 2 Diabetes mellitus consists of an array of dysfunctions characterized by hyperglycemia, resulting from the combination of resistance to insulin action and/or inadequate insulin secretion. It is usually associated with dyslipidemia, which increases risk of cardiovascular events leading to morbidity & mortality. Thyroid dysfunction has been frequently encountered in diabetes patients with hypothyroidism being the most common type of dysfunction.2 Hypothyroidism, an important cause of secondary dyslipidemia, is often accompanied with increased levels of total cholesterol & low density lipoprotein-cholesterol (LDL-C).3 By studying the association of thyroid hormones & lipid profile in diabetes patients, we can enhance the knowledge about the interrelation between diabetes, thyroid hormones and lipid profile.

Materials and Methods

This is a case control study conducted in a tertiary care hospital comprising of 50 Type 2 DM cases attending outpatient department and 50 age & sex matched healthy controls.

Patients with history of thyroid disorders, chronic liver disease, chronic kidney disease, cardiovascular disease, pregnant & lactating women and patients on drugs affecting thyroid hormones were excluded from the study.

Sample collection

After overnight fast, 5 ml of venous blood was collected in a plain tube and a tube containing EDTA. Serum and plasma are separated by centrifugation at 3000 rpm for 10 minutes. Fasting blood glucose and Postprandial blood glucose estimated by Glucose oxidase- peroxidase method in ERBA XL 640 auto analyser. Total cholesterol was estimated by cholesterol oxidase phenol 4-aminoantipyrine peroxidase (CHOD PAP) method, Triglycerides by Glycerol phosphate oxidase phenol 4-aminoantipyrine peroxidase (GPO PAP) method, and HDL-C by PEG/CHOD-PAP method in ERBA XL 640 auto analyser.

Low-Density Lipoprotein cholesterol (LDL-C) was calculated using Friedewald's equation

LDL- Cholesterol = total cholesterol - (HDL cholesterol + triglycerides/ 5) T3, T4, TSH (normal range : T3: 0.69 – 2.15 ng/ml, T4: 5.2 -12.7 µg/dl, TSH :0.3-4.5 μIU/ml) estimated by chemiluminescence immunoassay method in Maglumi 800.

Statistical analysis

Statistical analysis was done by IBM SPSS Statistics for Windows, Version 20.0. Mean and SD were used to summarize the continuous variables. Independent samples t test was used to test the significance in difference between the parameters for cases and controls. Pearson's correlation coefficient was used to check the linear relation between parameters of lipid profile and thyroid profile. A P value of <0.05 was considered as statistically significant.

Result

Age and sex distribution is shown in Table 1 and Table 2. Cases include 28 males & 22 females whereas controls include 25 males & 25 females with mean age of 51.85±12.42 & 51.37±12.81 respectively.

Table 1

Age distribution of cases and controls

Variable

Group

Mean

SD

P value

Age (Yrs)

Cases

51.85

12.42

0.92

Controls

51.37

12.81

Table 2

Gender distribution of cases and controls

Gender

N (Cases)

%

N (Controls)

%

Male

28

56.0

25

50.0

Female

22

44.0

25

50.0

Figure 1

Comparison of FBS and PPBS in cases and controls

https://typeset-prod-media-server.s3.amazonaws.com/article_uploads/eb827eb0-90f4-4c49-a3a6-96c106cf45df/image/e3c95b97-71d6-4111-abd2-a8240eb1d40c-uimage.png

The mean fasting blood glucose and post prandial blood glucose level among cases and controls which was found to be statistically significant.

Figure 1 shows the mean fasting blood glucose and post prandial blood glucose level among cases and controls which was found to be statistically significant.

Table 3

Biochemical parameters of cases and controls

Variable

Group

Mean

SD

P value

FBS (mg/dL)

Cases

199.30

29.61

0.0008

Controls

92.26

13.99

PPBS (mg/dL)

Cases

250.25

28.29

0.0005

Controls

128.37

20.61

TC (mg/dL)

Cases

208.50

29.67

0.007

Controls

174.21

17.41

TG (mg/dL)

Cases

162.50

23.55

0.0001

Controls

99.79

17.56

LDL-C (mg/dL)

Cases

141.80

18.39

0.0004

Controls

87.47

11.65

HDL-C (mg/dL)

Cases

27.9

4.3

0.0005

Controls

50.5

8.7

T3 (ng/mL)

Cases

0.59

0.08

0.029

Controls

1.79

0.12

T4 (µg/dL)

Cases

4.5

1.90

0.005

Controls

8.84

1.17

TSH (μIU/mL)

Cases

4.98

1.32

0.0002

Controls

1.97

0.98

Table 3 shows that levels of TC, TG, LDL-C were significantly higher in T2DM patients, while HDL-C were significantly lower in T2DM patients as compared to controls. Serum levels of T3 and T4 were significantly lower in cases compared to controls whereas the level of serum TSH was significantly higher in cases as compared to the controls.

Figure 2

Correlation between TSH and lipid profile

https://typeset-prod-media-server.s3.amazonaws.com/article_uploads/eb827eb0-90f4-4c49-a3a6-96c106cf45df/image/3b015fc6-0cf6-4e1a-b6c9-64aa1ac09465-uimage.png

Figure 2 shows that TSH is significantly and positively correlated with LDL-C, TG and TC and negatively correlated with that of HDL-C.

Figure 3

Correlation between T3 and lipid profile

https://typeset-prod-media-server.s3.amazonaws.com/article_uploads/eb827eb0-90f4-4c49-a3a6-96c106cf45df/image/242554fa-00a9-434b-9d8b-2fca11151f2d-uimage.png

Figure 4

Correlation between T4 and lipid profile

https://typeset-prod-media-server.s3.amazonaws.com/article_uploads/eb827eb0-90f4-4c49-a3a6-96c106cf45df/image/4355b69c-adef-4fba-aaf7-a59b683d5144-uimage.png

T3 & T4 levels are significantly and negatively correlated with LDL-C, TG and TC and positively correlated with that of HDL-C as shown in Figure 3, Figure 4.

Discussion

In this present study, higher serum level of Total cholesterol, triglycerides & LDL –C seen in T2DM patients. Dyslipidemia in diabetes is due to low activity of lipoprotein lipase or limited lipoprotein clearance.4

Result of the present study showed that the levels of serum T3, T4 were significantly lower in diabetes while serum TSH was significantly higher in diabetes when compared to that of controls. These findings were consistent with that found by Sarala Devi Tenepalli et al.,3 Jiffri EH et al.,4 Demitrost et al.,5 In diabetic patients, the nocturnal TSH peak is blunted and the TSH response to TRH is impaired,6 resulting in reduced iodide uptake by the thyroid gland that limits T3 and T4 production.7

Also this study shows TSH is significantly and positively correlated with LDL-C, TG and TC and negatively correlated with that of HDL-C. T3 & T4 levels are significantly and negatively correlated with LDL-C, TG and TC and positively correlated with that of HDL-C. Our findings are in harmony with that of Palacios et al.,8 Asvold et al.,9 Saeed W et al.,10 Decreased levels of thyroid hormones attenuate activity of lipoprotein lipase (LPL), the enzyme responsible for clearance of TG-rich lipoproteins and thus lead to increased levels of TG in the serum.11 Thyroid hormones such as T3 have been demonstrated to regulate LDL receptors by directly binding to thyroid hormone responsive elements (TREs) and controlling sterol regulatory element-binding protein. In hypothyroidism, decreased thyroid hormones lead to reduced expression of LDL receptors, which may attenuate cellular uptake of LDL-C from circulation and catabolism of LDL-C and finally result in increased levels of circulating TC.12, 13

Conclusion

Thyroid dysfunction is associated with lipid dysregulation in T2DM patients. By maintaining good glycemic control in T2DM, we can prevent the development of thyroid dysfunction and its complications. Also, screening for thyroid disorders and early intervention in T2DM patients can reduce morbidity due to dyslipidemia. Hence thyroid function tests may be included as part of routine investigations in patients with Type 2 DM.

Source of Funding

None.

Conflict of Interest

The authors declare that there is no conflict of interest.

References

1 

P Saeedi I Petersohn P Salpea B Malanda S Karuranga N Unwin Global and regional diabetes prevalence estimates for 2019 and projections for 2030 and 2045: Results from the International Diabetes Federation Diabetes Atlas, 9th editionDiabetes Res Clin Pract201915710784310.1016/j.diabres.2019.107843

2 

P Anveetha Study of thyroid profile in patients with Type 2 Diabetes MellitusInt J Pharma Bio Sci2015512430

3 

SD Tenepalli PR Kulkarni N Pyadala A comparative evaluation of lipid profile and hormones in patients with type 2 diabetes mellitus: A hospital-based case control studyInt J Biochem201741115

4 

EH Jiffri Relationship between Lipid Profile Blood and Thyroid Hormones in Patient with Type 2 Diabetes MellitusAdv Obes Weight Manag Control2017661788210.15406/aowmc.2017.06.00176

5 

L Demitrost S Ranabir Thyroid dysfunction in type 2 diabetes mellitus: A retrospective studyIndian J Endocr Metab2012163345

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M Hage MS Zantout ST Azar Thyroid Disorders and Diabetes MellitusJ Thyroid Res201120111710.4061/2011/439463

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Y Zhang P Lu L Zhang Association between lipids profile and thyroid parameters in euthyroid diabetic subjects:a cross-sectional studyBMC Endocr Disord201515115

8 

S Santos-Palacios A Brugos-Larumbe F Guillén-Grima JC Galofré A Cross sectional study of the association between circulating TSH level and lipid profile in a large Spanish populationClin Endocrinol (Oxf)201379687481

9 

V Asvold The association between TSH within the reference range and serum lipid concentrations in a population-based study. The HUNT studyEur J Endocrinol200715621816

10 

WM Saeed SFA ElRahman EA Abdrabo Evaluation of Thyroid Function Test in Sudanese Patients with Type 2 Diabetes MellitusJ Med Biol Sci Res2016281315

11 

CV Rizos MS Elisaf EN Liberopoulos Effect of thyroid dysfunction on Lipid profileOpen Cardiovasc Med J201157684

12 

Y Chen X Wu R Wu X Sun B Yang Y Wang Changes in profile of lipids and adipokines in patients with newly diagnosed hypothyroidism and hyperthyroidismSci Rep201610.1038/srep26174

13 

DJ Shin TF Osborne Thyroid Hormone Regulation and Cholesterol Metabolism Are Connected through Sterol Regulatory Element-binding Protein-2 (SREBP-2)J Biol Chem20032783634114810.1074/jbc.m305417200



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Article type

Original Article


Article page

25-28


Authors Details

Pangajam P, Veena Juliette A


Article History

Received : 23-01-2021

Accepted : 01-02-2021

Available online : 03-05-2021


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