Comparison of thyroid profile in
premenopausal and postmenopausal women: A case control study
G.S
Chandrashekhar
Dr. G.S
Chandrashekhar, Senior Physician & Cardiodiabetologist, Medical Director,
Adarsha Super Speciality Hospital, Udupi, Karnataka, India.
Adarsha Multi Speciality
Hospital, Udupi, Karnataka. E-mail: drgsc0606@gmail.com
Abstract
Introduction : After
menopause, diminishedgonadal hormones are found to influence
thyroid status. There are a few published literature in this area, to the best of our knowledge. Aim
of the study was to compare thyroid profile of postmenopausal women with those
in reproductive age group as well as to find the correlation between age and
thyroid profile. compare thyroid profiles of young men with those in geriatric
age group iii. find if anygender differences in thyroid profiles. Methods: In a case control study,
thyroid profiles of 76 post menopausal women and 131 women in reproductive age
group were compared. Thyroid profile of 78 young men was compared with that of
24 men in geriatric age group. Genderdifferencesin thyroid profile were studied
by comparing thyroid profiles of 207women and 102 men. Statistical analysis was
carried out using MannWhitney U test and Linear regression analysis. Results: A significantly higher TSH
levels (P<0.05) and decreased T3 (P<0.0001) were observed in
postmenopausal women compared to the controls. There was no statistically
significant difference in thyroid profiles among men in geriatric age group and
young men. There was a significant elevation of TSH in women compared to men (P<0.05).
A negative correlation between age and T3 levels was observed in women. Conclusion: Subclinical hypothyroidism was
observed in post menopausal women in our setting. A higher tendency of women
having subclinical hypothyroidism compared to men was also observed. This
suggestsa necessity to assess functional status of thyroid gland periodically
in the post menopausal period.
Key words: Thyroid profile,
Menopause, Gender difference
Author Corrected: 24th October 2018 Accepted for Publication: 30th October 2018
Introduction
Menopauseis
a condition where there is cessation of menstruation under the influence of
reproductive hormones. The menopause is
characterized by wide variability in both FSH and estradiol in the blood. In menopause,
the ovaries producelessestrogen and these changes in estrogenexposure have
important effects on most tissues in the body.
Endocrine
glands exhibit changes as the age advances. Age related fall in circulating T4,
reduction in TSH bioavailability, reduced responsiveness of thyroid gland to
TSH can result in increased TSH secretion in the absence of overt thyroid
disease. Subclinical hypothyroidism with normal free T4 and raised TSH is found
to be common in elderly [1,2]. Gender specific alterations in TSH and FT4has
also been reported in which elderly women had elevated TSH, without any
alterations in FT4 [3]. Thesehormones influence other systems in the body
aswell. Thyroid gland is one among them.Thyroid hormone regulates body
metabolism, including reproductive functions. Disorders of thyroid gland are
common in women.
We
could finda fewAmerican studies in which higher TSH levels were reported in
post menopausal women [4,5]. One of the previous studies suggested an elevation
of TSH in postmenopausal women [6].There is a scarcity of literature in Indian
settings which focus on thyroid status in post menopausal women.
Objectives
Aims
of this study were to compare thyroid profile of postmenopausal women with those
in reproductive age group as well as to find the correlation between age and
thyroid profile. To compare thyroid profiles of young men with those in
geriatric age group& to find if anygender differences in thyroid profiles
Methodology
Study design- The
case control study was conducted in Adarsha Hospital, Udupi. Ethics committee approval
was sought before starting the study.
Inclusion criteria: Thyroid
profiles of207women were studied, out of which 131 were inreproductive age
group, 76 were postmenopausal. Thyroid profiles of 102 men were assessed, out
of which 24 were in geriatric age group and 78 were young men. Mean ages of
premenopausal and post menopausal women were 34.91±0.91 years and 62.63±1.15
years respectively. Mean ages of young and geriatric men were 42.06±1.57 years and
71±1.49 years respectively. Overall mean age of women and men were 45.09±1.17 years
and 48.87±1.75 years respectively.
Exclusion criteria for
cases: diabetics, hypertensives, known thyroiddisorders
Sample collection and
analysis- Five ml of venous blood sample was collectedin plain
tubes by puncturing antecubital vein with aseptic precautions. Samples were
centrifuged at 3000 rpm for 15 minutes. Serumwas analyzed for thyroid hormones
and TSH with commercially available kits in hormone analyzer Mini Vidas, which
works on the principle of Immunofluorescence.
Statistical analysis- Statistical
analysis was carried out using the software SPSS 16. Mann Whitney U test was used
to compare thyroid profiles. Correlation of thyroid profile with age was
computed by linear regression analysis.
Results
A significantly
higher TSH levels (P<0.05) and decreased T3 (P<0.001) were observed in
postmenopausal women compared to the controls (fig 1). There was no
statistically significant difference in thyroid profiles among men in geriatric
age group and young men (P>0.05) (fig 2). However TSH was insignificantly
high in geriatric group. There was no significant gender difference in thyroid profile
(P>0.05) except for serum TSH levels which was significantly high in women
(P<0.05)(fig 3).
There was a significant
negative correlation between age and T3 levels in women (correlation coefficient
(r) = -0.2018.r2 = 0.04074; P=0.0035). There was no significant
deviation of runs from the linearity (Fig 4). There was no significant
correlation between age and T4, TSH (P>0.05).
Fig
4: Linear regression correlation analysis ofAge and T3.
Discussion
A
significant elevation in TSH and decline in T3 levels were observed in post
menopausal women (fig 1). Study by Adiga et alfound a significant elevation in
TSH levels (P<0.05) as well as no significant decline in thyroid hormones in
post menopausal women compared to those in reproductive age group [6]. A
positive correlationhas also been found between TSH and age.Similar results
were observed by Rojas et al,Pearce et al and Hollowell et al [4,5,7]. Altered
thyroid functions can be explained as an age-related fall in thyroid hormones
or reduced responsiveness of thyroid to TSH in the absence of overt thyroid disease.
It also may be an occult thyroid disease or just an age-related alteration in
TSH set point [8,9].However contradictoryreports are available, which suggest a
lower TSH levels in post menopausal women [10,11].
Thewomen
healthrelies in a delicate balance of hormones, such as estrogen, progesterone,
and testosterone. The thyroid hormones influence the functioning of all major
organs along with reproductive system development and overall body metabolism.In
women, diseases of the thyroid gland are among the most prevalent disorders
worldwide, second only to diabetes[12].With time, overt hypothyroidism can
develop in menopausal age, the symptoms of which can be similar to
postmenopausal complaints and are clinically difficult to differentiate. There
can also be an absence of clinical symptoms.
Elevated
TSH in elderly, especially in women can be physiological or pathological.
History of nutritional status, associated illness and follow up with TSH
measurement helps to differentiate.
The
American Thyroid Association (ATA), the Endocrine Society and the American
Association of ClinicalEndocrinologists (AACE) had recommended aggressive case
finding in elderly women. Thyroid stimulating hormone (TSH) is the preferred
test to assess thyroid function as stated by National Academy of Clinical Biochemistry[13].It
has been reported by the 2012 clinical practice guidelines co-sponsored by the
AACE and ATA that the serum TSH is the single best screening test for primary
vast majority of outpatient clinical situations[14]. It is evident from the
various study results that periodic screening of post menopausal women for
thyroid dysfunction is very much needed.
We
could not demonstrate any significant alterations in thyroid status of elderly
compared to young adults due to the small sample size of geriatric population.
However TSH has been reported to be increased in elderly. The causes may be
anti-thyroid antibodies, nutritional deficiency of iodine, hiddenthyroid
autonomy etc. Sleep disturbances and altered sleep patterns with increasing age
may lead to increase in TSH levels [15]. Aging is associated with changes in
pituitary-thyroid axis. There is aprogressive shift in the serum TSH
distribution curve towards higher TSH values with increasing age [2].Many
endocrine systems exhibitchanges with aging in the absence of overt disease
thus age-related fall in circulating T4, reduction in TSH bioactivity or
reduced responsiveness of the thyroid to TSH could result in increased TSH secretion.
Another possibility is that it may be due to occult thyroid disease in older
people or simply an age -related alteration in TSH set point[8,9]. It might be
possible that variation in the level of serum TSH is not great enough
(nonsignificant), as the endocrine functions those are essential to life, such
as adrenal and thyroid functions, show a minimal overall change in basal levels
with ageing[9,16].
Rojas
et al. found higher TSH level in postmenopausal women compared to premenopausal
women [7]. They found average TSH values increased with age, although the changes
between groups were not significant. American study by Pearce et al point
towards increased TSH levels in post menopausal women [4]. Hollowell et alfound
higher TSH levels in women in the older age group in the National Health and
Nutrition Examination Survey –NHANESconducted in United States on large
population [5]. An Italian studybyMariotti et al. found significantly higher
TSH levels in younger women and claim that due to an age-related decrease in
TSH secretion by the pituitary [10]. Hershmanet al found the mean TSH in older
womenwas slightly but significantly lower than that in middle-aged women [11].
Limitations
of the study was small sample size of geriatric population.
Conclusion
Subclinical
hypothyroidism wasobserved inpost menopausal women in our setting. A higher
tendency of women having subclinical hypothyroidism compared to men was also
observed. This suggests a necessity to assess functional status ofthyroid glandperiodically
inthe post menopausal period.
Conflicts of Interest:
None
Authors
contribution: Dr G.S Chandrashekhar is the only
author for the article, who planned the study, carried out the research and
prepared the manuscript.
What
this study adds to existing Knowledge:The present study
contributes to the existing knowledge as it suggests a routine screening of
thyroid function tests in postmenopausal women.
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How to cite this article?
G.S Chandrashekhar. Comparison of thyroid profile in premenopausal and postmenopausal women: A case control study. Int J Med Res Rev 2018; 6(07):367-371. doi:10.17511/ijmrr.2018.i07.05.