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International Journal of Advances in Medicine | March-April 2018 | Vol 5 | Issue 2 Page 281
International Journal of Advances in Medicine
Vijayan V et al. Int J Adv Med. 2018 Apr;5(2):281-288
http://www.ijmedicine.com
pISSN 2349-3925 | eISSN 2349-3933
Original Research Article
Assessment of carotid intima-media thickness in hypothyroidism and
the effect of thyroid replacement therapy
Varun Vijayan1, Jayasingh K.2, Jayaraman G.3, Siva Ranganathan Green4*, Deyagarasan E.5
INTRODUCTION
Carotid artery intima-media thickness (CAIMT) is a
generally acknowledged measure of subclinical
atherosclerotic alterations. It is used to estimate vascular
function in clinical analyses to assess the efficacy of
interventions that reduce atherosclerosis and related
diseases.1 This parameter has been listed in the European
guidelines for prevention of cardiovascular diseases, and
0.9 mm is the threshold value for CAIMT. Advancement
of atherosclerosis is indicated when the value of CAIMT
is over the threshold.2 Several risk factors for
atherosclerotic cardiovascular disease have been
recognized, including endothelial dysfunction,
hyperhomocysteinemia, elevated C-reactive protein
(CRP) levels, and insulin resistance. The effect of
hypothyroidism on vascular risk factors for
atherosclerosis has been investigated in many studies.
ABSTRACT
Background: Carotid artery intima-media thickness (CAIMT) measurement in hypothyroidism will help assess the
progression of atherosclerosis and timely intervention may prevent vascular complications.
Methods: This study included 30 clinical hypothyroid (CH), 30 subclinical hypothyroid (SCH) and 30 euthyroid. As
per procedure, informed consent was taken from the patients in prescribed formats before their participation in the
study. Patients were divided into 3 groups of CHs, SCH and Controls after obtaining the thyroid function test values.
CAIMT on the right side was measured in the three groups for comparison. Other parameters included age, sex,
height, weight, body mass index (BMI), total cholesterol and triglycerides. After 4 months of levothyroxine therapy,
CAIMT, total cholesterol and triglycerides were reassessed.
Results: The CAIMT was increased in CH and SCH group when compared to euthyroid individuals. The mean
CAIMT in CH group was 0.60±0.009cm, in SCH group it was 0.055±0.010 cm and in controls it was 0.047±0.006
cm. After 4 months of levothyroxine therapy, there was no change observed in the mean CAIMT values.
Conclusions: CAIMT levels were increased in CH and SCH group when compared to euthyroid group. There was no
regression of CAIMT after 4 months of levothyroxine therapy.
Keywords: Carotid artery intima-media thickness, Clinical hypothyroidism, Subclinical hypothyroidism
1Resident, 2Professor and Head, Department of General Medicine, Mahatma Gandhi Medical College and Research
Institute, Sri Balaji Vidyapeeth University, Puducherry, India
3Associate Professor, Department of Radiology, Mahatma Gandhi Medical College and Research Institute, Sri Balaji
Vidyapeeth University, Puducherry, India
4Associate Professor, 5Assistant Professor, Department of General Medicine, Mahatma Gandhi Medical College and
Research Institute, Sri Balaji Vidyapeeth University, Puducherry, India
Received: 02 February 2018
Accepted: 19 February 2018
*Correspondence:
Dr. Siva Ranganathan Green,
E-mail: srgreen@mgmcri.ac.in
Copyright: © the author(s), publisher and licensee Medip Academy. This is an open-access article distributed under
the terms of the Creative Commons Attribution Non-Commercial License, which permits unrestricted non-commercial
use, distribution, and reproduction in any medium, provided the original work is properly cited.
DOI: http://dx.doi.org/10.18203/2349-3933.ijam20180956
Vijayan V et al. Int J Adv Med. 2018 Apr;5(2):281-288
International Journal of Advances in Medicine | March-April 2018 | Vol 5 | Issue 2 Page 282
Variations in flow-mediated, endothelium-dependent
vasodilatation, which occurs early in atherogenesis, have
been noted in patients with hypothyroidism. It is tentative
whether it can be attributed to a direct effect of thyroid
hormone deficiency or facilitated through the elevated
cholesterol levels induced by hypothyroidism.3 Prompt
treatment must be initiated for all patients with a TSH
value of >10µIU/L.4
Hypothyroidism has been associated with atherosclerosis,
which in turn may lead to cardiovascular events.
Subclinical hypothyroidism in our country is generally
undiagnosed and if diagnosed, patients discontinue
treatment and lose follow up due to the lack of physical
symptoms in most. In this study, we have assessed the
CAIMT of hypothyroid patients (clinical and subclinical)
and compared it with euthyroid individuals to have a
better understanding of association of atherosclerotic
changes that tend to occur in these patients.
METHODS
This research study was conducted in the Department of
General Medicine, Mahatma Gandhi Medical College
and Research Institute, Puducherry, a tertiary health care
centre. The samples were collected during the period of
18 months from January 2016 to June 2017. The study
was initiated with 30 clinical hypothyroid, 30 subclinical
hypothyroid patients and 30 euthyroid individuals equally
distributed in both genders.
Inclusion criteria
• Age: 18-65 years.
• Thyroid hormone dysfunction assessed by laboratory
findings.
• Newly diagnosed hypothyroid patients.
• Euthyroid individuals
Exclusion criteria
• Diabetes
• Hypertension
• TSH < 10 µIU/ml
• Previous h/o CAD.
• Patients already on thyroid replacement therapy.
• Renal Failure.
• Malignancies
• Patients on lipid lowering drugs.
• Smokers.
Brief explanation of the procedure
Patients were divided into 3 groups
• Group 1 - Subclinical Hypothyroidism (SCH)
containing 30 patients. [Elevated TSH (10 – 20
µIU/ml) but FreeT4 and FreeT3 within normal
ranges]
• Group 2 - Clinical Hypothyroidism (CH) containing
30 patients. [Elevated TSH, Low FreeT4 and FreeT3]
• Group 3 - Euthyroid individuals (Control) containing
30 patients. [Normal TSH, FreeT4 and FreeT3].
Age, sex, height, weight, thyroid profile, total cholesterol,
triglycerides and CAIMT were measured and recorded in
all patients fulfilling the inclusion criteria. Subjects were
age and sex matched. Hypothyroid patients were started
on levothyroxine therapy. They were followed up at the
end of 4 months to reassess their thyroid profile, lipid
status and CAIMT. The data was documented
accordingly. Normal individuals were explained about
the benefits of the investigations and after obtaining their
consent thyroid profile, lipid profile, and carotid intima
media thickness were measured and recorded.
CAIMT was measured with Mindray DC-8 ultrasound
equipment using the linear transducer of 7 MHz
frequency. The subject was placed in supine position with
his/her neck in extension and rolled contra-laterally by
about 45o. The intima-media thickness was taken on the
far wall, 10 mm proximal to the right common carotid
bulb. IMT was evaluated as the distance between the
lumen intima and the media-adventitia interface.5 A
single radiologist manually measured the IMT and he was
blinded to the identity of the subjects.
Venous blood samples were drawn between 7 am and 8
am after an overnight fast. Thyroid function test was done
by chemiluminescent immunometric assay. The normal
values for TSH according to our lab were 0.3 – 4.20
µIU/ml, for FT4: 0.93 – 1.76 ng/dl, and FT3: 2.0 – 4.4
pg/ml.
Total cholesterol was estimated using an enzymatic
method (cholesterol oxidase and peroxidase method) and
triglyceride was measured using glycerol-3-phosho
oxidase (GPO) method.
Thyroid function was evaluated considering three
categories: clinical hypothyroidism, subclinical
hypothyroidism and euthyroid. The collected data were
compared using One way ANOVA test.
Nonparametric tests (Wilcoxon signed rank test and
Kruskal-Wallis test) were used for univariate analysis of
triglyceride values.
The review parameters were compared between the two
groups (clinical and subclinical hypothyroidism) using
the Paired t-test.
p <0.05 was considered statistically significant.
RESULTS
A total of 90 patients were taken for this study. They
were divided into three groups of subclinical, clinical and
euthyroid, with each group containing 30 participants
Vijayan V et al. Int J Adv Med. 2018 Apr;5(2):281-288
International Journal of Advances in Medicine | March-April 2018 | Vol 5 | Issue 2 Page 283
with mean age of 33.90±10.69, 35.53±9.95 and
37.93±9.78 years respectively. p value was 0.307 (Table
1). Among all the 3 groups, the percentage of male
subjects were 6.7% and the percentage of female subjects
were 93.3%. (Table 2). The mean BMI was 24.66±4.13,
27.07±4.89 and 22.86±3.01 kg/m2 in SCH, CH and
euthyroid group respectively (Table 3).
Table 1: Mean age of study subjects.
Mean (in years)
Standard Deviation
p value *
Subclinical (n=30)
33.90
10.69
0.307
Clinical (n=30)
35.53
9.95
Euthyroid (n=30)
37.93
9.78
*One way ANOVA test
Table 2: Gender distribution of study subjects.
Subclinical
Clinical
Euthyroid
Total
N
%
N
%
N
%
N
%
Male
2
{6.7}
2
{6.7}
2
{6.7}
6
{6.7}
Female
28
{93.3}
28
{93.3}
28
{93.3}
84
{93.3}
Total
30
{100.0}
30
{100.0}
30
{100.0}
90
{100.0}
Fisher’s exact p value=1
Table 3: Mean body mass index (BMI) of the study participants (N=90).
Mean
Standard Deviation
P value *
Subclinical (n=30)
24.66
4.13
0.006
Clinical (n=30)
27.07
4.89
Euthyroid (n=30)
22.86
3.01
*One way ANOVA test
In our study, we found that the mean TSH level for the
SCH group was 15.58±3.13µIU/ml, for CH
66.487±34.815µIU/ml and for euthyroid it was
2.47±1.25µIU/ml. In the SCH group the mean FT3 level
was 2.35±0.69pg/ml while in the CH group it was
1.61±0.58pg/ml and in euthyroid group the mean was
2.35±0.38pg/ml. The mean FT4 in the SCH group was
1.23 ± 0.33 ng/dl, which was within the normal limits.
While in the CH group it was 0.82 ± 0.49 ng/dl which is
lower than the SCH group. In the euthyroid group, mean
FT4 was 1.77 ± 0.23 ng/dl. The p value in all the three
groups was < 0.0001 (Table 4).
Table 4: Mean TSH, FT3 and FT4 of study participants.
TSH
FT3
FT4
Mean (µIU/ml)
SD
Mean (pg/ml)
SD
Mean (ng/dl)
SD
Subclinical (n = 30)
15.58
3.13
2.35
0.69
1.23
0.33
Clinical (n = 30)
66.48
34.81
1.61
0.58
0.82
0.49
Euthyroid (n = 30)
2.47
1.253
2.35
0.38
1.77
0.23
p Value*
<0.0001
<0.0001
<0.0001
*One way ANOVA
Total cholesterol values in the SCH group ranged from
172 to 237 mg/dl. The mean was 201.43 ± 18.26 mg/dl.
In the CH group the values ranged from 182 to 352 mg/dl
and the mean was 233.27 ± 42.49 mg/dl. The mean in
euthyroid group was 154.57 ± 25.23 mg/dl.
The p value was < 0.0001 which was statistically
significant. Kruskal Wallis test was used to calculate the
median triglyceride values because the variation in
triglyceride levels mandated the use of a non-parametric
method. In the CH group, the lowest triglyceride range
varied among patients from 63 mg/dl to as high as 1533
mg/dl. The calculated median triglycride was 129 mg/dl.
In the SCH group the lowest value we obtained was 92
mg/dl and the highest was 347 mg/dl. The calculated
median was 207mg/dl. 17 study participants had TG >
200 mg/dl. Median triglyceride of euthyroid subjects
were 102.5 mg/dl. There was a significant difference
Vijayan V et al. Int J Adv Med. 2018 Apr;5(2):281-288
International Journal of Advances in Medicine | March-April 2018 | Vol 5 | Issue 2 Page 284
observed in the triglyceride levels between the 3 groups
with a p value < 0.0001 (Table 5).
The mean CAIMT on the right side was estimated for all
the three groups. In the SCH group the mean was 0.55 ±
0.1mm and in the CH group it was 0.60 ± 0.09mm.
Although within the normal range CAIMT was increased
in the SCH and CH group when compared with euthyroid
controls with a mean CAIMT of 0.47 ± 0.06 mm. The p
value was < 0.0001 which was statistically significant.
The mean CAIMT was more in the CH group when
compared with the SCH group (Table 6).
Table 5: Mean total cholesterol and median triglyceride levels of study participants.
Total cholesterol
Triglyceride
Mean (mg/dl)
SD
Median (mg/dl)
Inter quartile range
Subclinical (n = 30)
201.43
18.26
207
184.5-232
Clinical (n = 30)
233.27
42.49
129
101.5-164
Euthyroid (n = 30)
154.57
25.23
102.5
90-126.5
p Value
<0.0001*
<0.0001#
*One way ANOVA test, #Kruskal Wallis test
Table 6: Mean CAIMT of the study participants.
Mean (mm)
Standard Deviation
p value *
Subclinical (n=30)
0.55
0.10
<0.0001
Clinical (n=30)
0.60
0.09
Euthyroid (n=30)
0.47
0.06
*One way ANOVA test
Comparison of parameters after 4 months of
levothyroxine among subclinical and clinical study
participants
After 4 months of levothyroxine therapy, the mean levels
of TSH was estimated in both clinical and subclinical
hypothyroidism groups. In the subclinical group, the
mean TSH levels reduced to 2.92 µIU/ml from 15.58
µIU/ml. In the clinical group, the mean TSH levels
reduced from 66.49 µIU/ml to 13.58 µIU/ml (Table 7).
The mean FT3 levels were calculated in both subclinical
and clinical hypothyroisim group after 4 months of
levothyroxine therapy. In the SCH group the mean FT3
was within the normal range 2.35 pg/ml and there was
not any significant difference after levothyroxine therapy,
with a mean of 2.39 pg/ml. In the CH group the mean
FT3 was on the lower side with a value of 1.61 pg/ml,
improved to 2.26 pg/ml after 4 months of levothyroxine
therapy with a p value of < 0.0001 and showed statistical
significance (Table 7).
Table 7: Comparison of TFT values - baseline and after 4 months of levothyroxine.
Subclinical (n = 30)
Clinical (n = 30)
Mean TSH Baseline ± SD (µIU/ml)
15.58 ± 3.13
66.49 ± 34.82
Mean TSH after 4 months ± SD (µIU/ml)
2.92 ± 1.60
13.58 ± 12.30
p Value*
<0.0001
<0.0001
Mean FT3 Baseline ± SD (pg/ml)
2.35 ± 0.69
1.61 ± 0.58
Mean FT3 after 4 months ± SD (pg/ml)
2.39 ± 0.36
2.26 ± 0.39
p Value*
0.7333
<0.0001
Mean FT4 Baseline ± SD (ng/dl)
1.23 ± 0.33
0.82 ± 0.49
Mean FT4 after 4 months ± SD (ng/dl)
1.70 ± 0.30
1.65 ± 0.34
p Value*
<0.0001
<0.0001
*Paired samples t test
The mean FT4 levels were calculated in both SCH and
CH group after 4 months of levothyroxine therapy. In the
SCH group the mean FT4 although within the normal
range of 1.23 ng/dl, there was improvement after
levothyroxine therapy, with a mean of 1.70 ng/dl. The p
value in SCH group was 0.7333 which was not
statistically significant. In the CH group the mean FT4
was on the lower side with a value of 0.82 ng/dl, which
improved to 1.65 ng/dl after 4 months of levothyroxine
therapy. The p value was < 0.0001 which was statistically
significant (Table 7).
Vijayan V et al. Int J Adv Med. 2018 Apr;5(2):281-288
International Journal of Advances in Medicine | March-April 2018 | Vol 5 | Issue 2 Page 285
Mean total cholesterol (TC) levels were estimated in SCH
and the CH group after 4 months of levothyroxine
therapy. In the SCH group, the mean TC reduced from
201.43 mg/dl to 145.73 mg/dl. In the CH group, the mean
TC reduced from 233.27 mg/dl to 162.97 mg/dl. The
calculated p value was <0.0001 in both the groups, which
was statistically significant (Table 8).
In the SCH group, the mean TG reduced from 205.90
mg/dl to 103.70 mg/dl, with a p value of < 0.0001 which
showed statistical significance. In the CH group, the
mean TG reduced from 197.53 mg/dl to 114.40 mg/dl.
The p value was calculated using Wilcoxon signed rank
test and was found to be 0.001 (Table 8).
The mean CAIMT, measured on the right side, in the
SCH group before initiating levothyroxine therapy was
0.55 ± 0.1 mm. After 4 months of levothyroxine therapy
the mean CAIMT had the same value of 0.55 ± 0.1 mm.
(p value 0.3256) In the CH group the mean CAIMT,
measured on the right side, was 0.60 ± 0.09 mm before
initiating on levothyroxine therapy. The mean CAIMT
was 0.61 ± 0.08 mm after 4 months of levothyroxine
therapy. (p value 0.0960) (Table 9).
Table 8: Comparison of TC and TG levels after 4 months of levothyroxine.
Subclinical (n = 30)
Clinical (n = 30)
Mean Total Cholesterol – Baseline ± SD (mg/dl)
201.43 ± 18.26
233.27 ± 42.49
Mean Total Cholesterol after 4 months ± SD (mg/dl)
145.73 ± 23.04
162.97 ± 24.71
p Value
<0.0001
<0.0001
Mean Triglyceride – Baseline ± SD (mg/dl)
205.90 ± 51.31
197.53 ± 265.48
Mean Triglyceride after 4 months ± SD (mg/dl)
103.70 ± 23.83
114.40 ± 38.90
p Value
<0.0001*
0.001#
*Paired samples t test #Wilcoxon signed rank test
Table 9: Comparison of CAIMT levels after 4 months of levothyroxine.
Subclinical (n = 30)
Clinical (n = 30)
Mean CAIMT – Baseline ± SD (in mm)
0.55 ± 0.1
0.60 ± 0.09
Mean CAIMT After 4 months ± SD (in mm)
0.55 ± 0.1
0.61 ± 0.08
p Value*
0.3256
0.0960
*Paired samples t test
DISCUSSION
The mean age in subclinical (SCH) and clinical
hypothyroidism (CH) were 33.90 ± 10.69 and 35.53 ±
9.95 years respectively. Since the subjects were age
matched, to avoid age related atherosclerosis to influence
CAIMT, there was no significant variation among the
three groups. In the euthyroid group the mean age was
37.93 ± 9.78 years. p value was 0.307. In a study done by
Unnikrishnan et al, the mean age of hypothyroid subjects
were 46 ± 14.68 years which is in sharp contrast to our
study, as the subjects were age matched.6
Among the three groups, the percentage of male subjects
in SCH and CH were 6.7% and the percentage of female
subjects were 93.3%. The subjects were sex matched to
avoid significant variation among the three groups.
Studies have shown that atherosclerotic changes develop
7 to 10 years later in women than in men.7
Mean BMI was 24.66 ± 4.13, 27.07±4.89 and 22.86±3.01
kg/m2 in SCH, CH and euthyroid group respectively. In
the SCH and CH group BMI was higher when compared
with euthyroid group. This shows the role thyroid
hormone plays in obesity. In a study done by Aziz KM
clinical hypothyroid patients had a higher BMI when
compared with SCH group (32.2±7.44 versus 29.4±5.7).8
The p value was 0.006 which was statistically significant.
Since management of patients with a serum TSH level of
less than 10 µIU/ml is controversial, in our study, we had
selected patients with TSH > 10µIU/ml.9 The mean TSH
level for the SCH was 15.5853.135 µIU/ml, for CH
66.48734.815 µIU/ml and for euthyroid controls, it was
2.4771.253 µIU/ml. Presently, the approach is routine
levothyroxine therapy for patients with a serum TSH of
more than 10.0 µIU/ml.10 Levothyroxine was initiated at
a dose of 0.5µg/kg and 1.6 µg/kg for subclinical and
clinical cases respectively.
After 4 months of levothyroxine therapy, on reassessing
the patients, FT3 improved in the CH group from mean
1.61 0.58 pg/ml to 2.260.39 pg/ml. In the SCH group,
the FT3 levels were in the normal range during the
starting phase the mean almost remained the same after 4
months.
FT4 levels the CH group improved from mean of
0.820.49 ng/dl to 1.650.34 ng/dl (P < 0.0001) after 4
months of therapy. The mean FT4 level was in the
normal range (1.230.33 ng/dl) in the SCH group at the
Vijayan V et al. Int J Adv Med. 2018 Apr;5(2):281-288
International Journal of Advances in Medicine | March-April 2018 | Vol 5 | Issue 2 Page 286
start of levothyroxine therapy and the levels improved
after 4 months (1.700.30 ng/dl).
In our study, the mean TC values in the SCH group was
calculated to be 201.4318.26 mg/dl which when
reviewed after 4 months of levothyroxine therapy
reduced to 145.7323.04 mg/dl (P < 0.0001). A meta-
analysis by Liu et al suggested that the serum total
cholesterol, levels were significantly increased in patients
with subclinical hypothyroidism when compared with
euthyroid individuals.11
According to a study conducted in Delhi by Asranna et al
the mean total cholesterol levels were significantly higher
in patients with SCH (173.72 mg/dl) which reduced after
3 months of levothyroxine treatment (161.86 mg/dl).12 In
another study of dyslipidemia in an Indian population of
100 patients with SCH and 52 euthyroid controls, total
cholesterol in the age group of 40-50 years were
significantly elevated.13
In CH group the mean TC of 233.2742.49 mg/dl
reduced to 162.9724.7 mg/dl. This finding was in
conjunction with a study conducted by Pearce et al.14
where mean TC was elevated in the study participants
(28452 mg/dl). Substitution therapy with levothyroxine
significantly improves lipid metabolism abnormalities.
Dyslipidemia is usually corrected within a period of 4-6
weeks of thyroxin replacement therapy.15
The mean triglyceride level in the CH group was
197.53265.48 mg/dl which reduced after 4 months of
levothyroxine therapy to 114.4038.90 mg/dl. Similarly,
in the SCH group the mean TG was 205.9051.31 mg/dl
which reduced to 103.7023.83 mg/dl.
This finding does not correlate with a study done in
Punjab by Singh et al.16 where the mean TG was
15742.39 mg/dl. The elevated TG levels in clinical
hypothyroidism may be attributed to a decline the
lipoprotein lipase activity, which impairs the clearance of
TG-rich lipoproteins.15,17 There are many previous reports
on the effect of thyroxine treatment on serum TG and
HDL levels and they all conclude that thyroxine
substitution has no effect on TG and HDL levels.18 In this
study we see a significant reduction in triglyceride levels
after 4 months of levothyroxine therapy.
The mean CAIMT on the right side was calculated for all
the three groups. In the SCH group the mean was
0.550.10 mm, and in the CH group, it was 0.600.09
mm. Although within the normal range, CAIMT was
increased in the SCH and CH group when compared with
euthyroid group with a mean CAIMT of 0.470.06 mm.
A similar finding was observed according to a study
conducted in India by Karoli et al where the mean
CAIMT obtained in SCH was 0.60.1 mm, in CH it was
0.7 0.14 mm and in euthyroid it was 0.50.08 mm.19
These values do correspond to the findings of this study
giving a better insight into the theory of increased
CAIMT in hypothyroid patients. Gao et al. in a meta-
analysis found that SCH was associated with an increased
carotid IMT, which may be due to elevated TSH and
dyslipidemia.20 Whether the increase in CAIMT can be
attributed to hypothyroidism alone is controversial as
most patients with deranged thyroid function tend to have
dyslipidemia. The results of a multi-ethnic study of
atherosclerosis show a positive association between
CAIMT progression and stroke. Cakal et al have
similarly established higher CAIMT in primary
hypothyroid patients.21,22
Their study has also found a positive correlation between
lipids, CAIMT, and TSH levels and have concluded that
CAIMT is an objective sign of accelerated atherosclerosis
in patients with primary hypothyroidism. In contrast to
these studies, Delitala et al in their study concluded that
thyroid hormone was not associated with carotid artery
plaque or increased CAIMT.23 Likewise, Jorde et al also
arrived at a conclusion that CAIMT and serum TSH
levels were not related and rather CAIMT was increased
in patients taking levothyroxine.24
On reviewing the subjects of this study after 4 months of
levothyroxine therapy, the CAIMT was reassessed. The
mean CAIMT did not change and had the same value of
0.550.1 mm (p = 0.3256) and 0.610.08 mm (p =
0.0960) in the SCH and CH group respectively. In a study
done by Nagasaki et al the basal CAIMT was
significantly higher in hypothyroid patients (0.630.018
mm) than in control subjects (0.550.02 mm, p <0.005).25
After 1 year of euthyroidism, 34 out of 35 patients
showed a significant decrease of CCA IMT, to
0.550.015 mm (p <0.0001), a level comparable to
euthyroid controls.
The changes in CAIMT could not be appreciated in this
study as the duration of treatment was too short to
improve CAIMT. The rate of progression of IMT in the
common carotid artery is approximately 0.01 mm/year.2
The regression of CAIMT observed by Zhao et al. was
after more than 6 months of levothyroxine therapy.2
Limitations of the study
• Thyroid peroxidase levels were not assessed.
• The sample size was rather small.
• The time period to assess the regression of CAIMT
was not sufficient. Other studies have used a period of
6 months to 1 year.
CONCLUSION
Hypothyroidism does contribute to an increase in the
carotid artery intima-media thickness. The CAIMT was
more in the clinical group when compared with
subclinical group. After 4 months of levothyroxine
Vijayan V et al. Int J Adv Med. 2018 Apr;5(2):281-288
International Journal of Advances in Medicine | March-April 2018 | Vol 5 | Issue 2 Page 287
therapy, there was no regression observed in either the
clinical or the subclinical group.
It was also observed that the total cholesterol and
triglyceride levels were elevated in both clinical and
subclinical group. After 4 months of levothyroxine
therapy, a considerable reduction was seen in both total
cholesterol and triglyceride levels.
Hence, we can conclude that a 4 month period is
inadequate to assess the progression and effect of
levothyroxine over the changes in CAIMT and that
levothyroxine therapy has a beneficial effect in reducing
total cholesterol and triglyceride levels.
ACKNOWLEDGEMENTS
Authors would like to acknowledge Dr. Jayasingh K.
(Professor and Head, Department of General Medicine),
Dr. Jayaraman G. (Associate Professor, Department of
Radiology), Dr. Siva Ranganathan Green (Associate
Professor, Department of General Medicine) and Dr.
Deyagarasan E. (Assistant professor, Department of
General Medicine) for their valuable suggestions,
continued guidance, support and encouragement in doing
this study.
Funding: No funding sources
Conflict of interest: None declared
Ethical approval: The study was approved by the
institutional ethics committee
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Cite this article as: Vijayan V, Jayasingh K,
Jayaraman G, Green SR, Deyagarasan E. Assessment
of carotid intima-media thickness in hypothyroidism
and the effect of thyroid replacement therapy. Int J
Adv Med 2018;5:281-8.
