Female Subclinical Hypothyroidism Research Articles

Associations between a normal-range free thyroxine concentration and ovarian reserve in infertile women undergoing treatment via assisted reproductive technology

BackgroundSome recent studies have shown that female subclinical hypothyroidism (SCH) is associated with diminished ovarian reserve (DOR). In this study, we aimed to investigate whether serum-free thyroxine (fT4) concentrations within the reference range are associated with ovarian reserve in women.MethodsThis cross-sectional study included 4933 infertile women with normal-range fT4 concentrations who received assisted reproductive technology treatment in our clinic. The data of women in different fT4 concentration tertiles (namely 12–15.33, 15.34–18.67, and 18.68–22 pmol/L) were compared with ovarian reserve markers, namely the anti-Müllerian hormone (AMH) concentration, the antral follicle count (AFC), and the number of aspirated oocytes. The primary outcomes were the AMH concentration and the risk of DOR, diagnosed as an AMH concentration < 1.1 ng/mL.ResultsThe average ages of women in the low-normal, middle-normal, and high-normal fT4 tertiles were 33.20 (standard deviation [SD]: 5.11), 32.33 (SD: 5.13), and 31.61 (SD: 5.10) years, respectively (p < 0.0001). AMH concentrations (adjusted mean: 3.32 [95% confidence interval {CI}: 3.16 to 3.50] vs. 3.51 [3.40 to 3.62] vs. 3.64 [3.50 to 3.80] ng/mL, p = 0.022) were significantly different between the fT4 concentration tertiles. The risk of DOR was significantly increased in the low-normal (adjusted odds ratio: 1.61 [95% CI: 1.01 to 2.58]) and middle-normal (1.47 [95% CI: 1.00 to 2.16]) tertiles compared with the high-normal tertile. Subgroup analysis showed that AMH concentrations were significantly different among the fT4 concentration tertiles in women aged < 35 years (adjusted mean: 3.94 [95% CI: 3.70 to 4.20] vs. 4.25 [4.11 to 4.39] vs. 4.38 [4.18 to 4.58], p = 0.028), whereas this difference was not significant in women aged ≥ 35 years (p = 0.534). The general additive models using fT4 as a continuous variable indicated that a lower fT4 concentration within the normal range was significantly associated with a lower AMH concentration (p = 0.027), a lower AFC (p = 0.018), a lower number of aspirated oocytes (p = 0.001), and a higher risk of DOR (p = 0.007).ConclusionLow-normal fT4 concentrations are associated with lower ovarian reserve in infertile women.

Analysis of Subclinical Thyroid Dysfunction and Metabolic Abnormality in 28568 Healthy People.

We analyzed the detection rates of metabolic syndrome (MetS) and subclinical thyroid dysfunction, including subclinical hyperthyroidism (SCHyper) and subclinical hypothyroidism (SCH), in healthy people, as well as their relationship. Clinical data were collected from 28,568 healthy individuals who underwent physical examinations. The detection rates of SCHyper, SCH, and MetS, as well as in different genders and ages, were analyzed. The detection rate of SCHyper and SCH in females was significantly higher than that in males (P < 0.001), but that of MetS in males was significantly higher than that in females (P < 0.001). In each age group, the detection rate of SCH in females was higher than that in males (P < 0.001). The detection rate of SCH was significantly different in different age groups (P < 0.001). The detection rates of hyperlipidemia (P < 0.001), obesity (P = 0.004), hypertension (P = 0.009), and hyperglycemia (P < 0.001) in the female SCH group were significantly higher than those in the normal group. The detection rates of hyperlipidemia (P = 0.006), obesity (P = 0.04), and hypertension (P = 0.04) in the male SCH group were higher than those in the normal group. The males with SCHyper were more prone to hyperlipidemia (P = 0.02) and obesity (P = 0.03). In addition, the female SCHyper group was not significantly different from the normal group (P > 0.05). Conclusively, the detection rate of SCHyper and SCH in females is higher than that in males, which increases with age. Attention should be paid to subclinical thyroid dysfunction in elderly people, especially females. Early individualized screening and early intervention should be carried out for people with abnormal metabolism.

A hospital based cross sectional study on subclinical hypothyroidism in females over fifty years of age and its relation to hypertension, diabetes mellitus and ischemic heart disease at a tertiary care hospital, Hyderabad

Background: Prevalence of subclinical hypothyroidism is more common in females compared to males and elderly age group. More studies are required to throw light on these aspects especially among elderly women with subclinical hypothyroidism and its association with prevalence of hypertension, diabetes and ischemic heart disease (IHD) among these women. The objective was to study prevalence of subclinical hypothyroidism among elderly females and its relation with the diabetes, hypertension and IHD.Methods: Hospital based cross-sectional study was carried out among 178 women of 50 years and more. Detailed history, clinical examination and routine investigations were carried out. Free T4, free T3 and TSH (thyroid stimulating hormone) levels were measured using electro chemiluminescent method. Presence of hypertension, diabetes mellitus, IHD was noted.Results: Prevalence of subclinical hypothyroidism was 24.7% and more in 61-70 years (38.5%). In 55% of the women the symptoms were absent. The most common symptom was fatigability and constipation. The prevalence of IHD among women with subclinical hypothyroidism was 22.7% compared to only 7.5% in women without subclinical hypothyroidism and this difference was found to be statistically significant (p&lt;0.05). For hypertension and diabetes, it was observed that the prevalence of these two conditions was slightly more in women without subclinical hypothyroidism but the difference was not found to be statistically significant (p&gt;0.05).Conclusions: Prevalence of subclinical hypothyroidism in the elderly women was high. Subclinical hypothyroidism was found to be significantly associated with IHD but not with hypertension and diabetes.

Sex differences in subclinical hypothyroidism and associations with metabolic risk factors: a health examination-based study in mainland China

BackgroundThe association between subclinical hypothyroidism (SCH) and metabolic risk factors in the general health examination-based population has been widely explored. However, the results have been inconclusive. Additionally, the sex differences in the prevalence of SCH and the association of SCH with metabolic risk factors remain unknown.MethodsWe conducted this cross-sectional study using data from health examination-based participants between June 2016 and April 2018 in our health examination centre. Sex differences SCH and the association of SCH with metabolic risk factors were explored.ResultsThe total prevalence of SCH was 3.40% among the 5319 included participants, and 4.90% among the 2306 female participants, which was much higher than the prevalence of 2.26% among the 3013 male participants (p < 0.05). In males, the difference between participants younger than 60 and aged 60 or older was not significant (p = 0.104); while in females, the difference between participants younger than 40 and participants aged 40 or older was statistically significant (p = 0.023). Multivariate logistic regression analysis demonstrated that age (OR = 0.568, p = 0.004), body-mass index (BMI) (OR = 5.029, p < 0.001) and systolic/diastolic blood pressure (SBP/DBP) (OR = 5.243, p < 0.001) were independent predictors of SCH in females, but no metabolic risk factor was significantly associated with SCH in males. Further analysis revealed that the prevalence was much higher in participants with one or two metabolic risk factors than in those with no above metabolic risk factors regardless of age (p < 0.01).ConclusionsOur study demonstrates that high BMI and/or high blood pressure are associated with SCH in female participants, and the prevalence of SCH among women with one or two metabolic risk factors ranges from 7.69–14.81%, which indicates that in such a population, serum concentrations of TSH and FT4 may be routinely screened in mainland China. Certainly, prospective, large-scale studies with long follow-up period are still necessary to further verify our results.

The efficiency of IVF/ICSI protocols in female subclinical hypothyroidism and thyroid autoimmunity

While overt hypothyroidism is a well-known risk factor for infertility, the association of subclinical hypothyroidism (SCH) or thyroid autoimmunity with reproductive failure has been still not cleared. This literature review focuses on the most current data linking SCH and/or thyroid autoimmunity with human reproduction, starting with the parameters of ovarian reserve and ending with generalized immunological alterations. The main ART outcome measures are as follows: number of oocytes retrieved, fertilization rate, embryo quality, implantation rate, clinical pregnancy rate per embryo transfer, miscarriage rate, and live birth rate. Summary of the information regarding the effect of levothyroxine supplementation on IVF outcome as well as workup and management of women with SCH and thyroid autoimmunity undergoing ART cycles is also presented in this review.

Investigation of Association between the High Risk of Female Subclinical Hypothyroidism and Inadequate Quantities of Twenty Intra-Thyroidal Chemical Elements

Subclinical hypothyroidism does affect fertility. The prevalence of subclinical hypothyroidism is 10-15 times more common in women than in men. Chemical elements, including trace elements, play important roles in thyroid function and fertility. The aim of this study was to evaluate whether significant difference of chemical element contents exists between female and male thyroids and how they can be related to the etiology of subclinical hypothyroidism. Thyroid tissue levels of twenty chemical elements: Al, B, Ba, Br, Ca, Cl, Cu, Fe, I, K, Li, Mg, Mn, Na, P, S, Si, Sr, V, and Zn were prospectively evaluated in 105 healthy persons (33 females and 72 males). It was found that for ages before 40 years means of Al, B, Ca, Cu, Fe, Li, Mg, S, and Zn content in female thyroid were lower than those in male thyroid. For ages over 40 years means of Ba, Br and Si content in female thyroid was higher whereas mean of Mg content was lower than those in male thyroid. Thus, inappropriate content of intra-thyroidal Al, B, Ba, Br, Ca, Cu, Fe, Li, Mg, S, Si, and Zn can be associated with the etiology of female subclinical hypothyroidism.

Investigation of Association between the High Risk of Female Subclinical Hypothyroidism and Inadequate Quantities of Twenty Intra-Thyroidal Chemical Elements

Subclinical hypothyroidism does affect fertility. The prevalence of subclinical hypothyroidism is 10-15 times more common in women than in men. Chemical elements, including trace elements, play important roles in thyroid function and fertility. The aim of this study was to evaluate whether significant difference of chemical element contents exists between female and male thyroids and how they can be related to the etiology of subclinical hypothyroidism. Thyroid tissue levels of twenty chemical elements: Al, B, Ba, Br, Ca, Cl, Cu, Fe, I, K, Li, Mg, Mn, Na, P, S, Si, Sr, V, and Zn were prospectively evaluated in 105 healthy persons (33 females and 72 males). It was found that for ages before 40 years means of Al, B, Ca, Cu, Fe, Li, Mg, S, and Zn content in female thyroid were lower than those in male thyroid. For ages over 40 years means of Ba, Br and Si content in female thyroid was higher whereas mean of Mg content was lower than those in male thyroid. Thus, inappropriate content of intra-thyroidal Al, B, Ba, Br, Ca, Cu, Fe, Li, Mg, S, Si, and Zn can be associated with the etiology of female subclinical hypothyroidism.

Prevalence of Subclinical hypothyroidism in females of Jammu region

Prevalence of Subclinical hypothyroidism in females of Jammu region

Possible Role of Inadequate Quantities of Intra-Thyroidal Bromine, Calcium and Magnesium in the Etiology of Female Subclinical Hypothyroidism

Possible Role of Inadequate Quantities of Intra-Thyroidal Bromine, Calcium and Magnesium in the Etiology of Female Subclinical Hypothyroidism

Possible Role of Inadequate Quantities of Intra-Thyroidal Cobalt, Rubidium and Zinc in the Etiology of Female Subclinical Hypothyroidism

Possible Role of Inadequate Quantities of Intra-Thyroidal Cobalt, Rubidium and Zinc in the Etiology of Female Subclinical Hypothyroidism

Prevalence and at early age onset of hypo and hyperthyroidism in postiodization era: a hospital based study from south India

Background: Thyroid dysfunction has been considered as one of the most common endocrine disorder in clinical practice throughout the world. Its increasing prevalence had led to the screening of general population in different parts of the world in order to investigate causes for rising incidence. A nationwide survey on epidemiology of thyroid dysfunction in selected cities of India suggested the need for further studies in order to have a more comprehensive analysis of epidemiological aspect for better awareness and control of this endocrine disorder. Aim: The major objective of the present study was to identify the prevalence and early age at onset of hypo and hyperthyroidism in post-iodization era based on a hospital based study. Materials and Methods: A total of 516 subjects visiting department of Medicine, Princess ESRA Hospital, Hyderabad, in age group of 10 to 75 years were included in the study from June 2013 to January 2014. Serum TSH, T3, and T4 assays were assessed by chemiluminescence method. Based on thyroid dysfunction test results, subjects were classified into Hypothyroidism, Subclinical Hypothyroidism and Hyperthyroidism. Results: The prevalence of hypothyroidism was highest in the females 33.52 % (n=173) as compared to males 2.32% (n=12) and hyperthyroidism in females 4.06% (n=21) and 0.19% (n=1) in males. Subclinical hypothyroidism in females was 7.55% (n=39). Conclusions: An inordinately high increase in the prevalence rate in women was observed particularly in the age group 21- 30years. Monitoring of thyroid profile is necessary to prevent adverse outcome at clinical and subclinical levels related to infertility, pregnancies and other complications.

Increased prevalence of subclinical hypothyroidism in females in mountainous valley of Kashmir

Background:Iodine-rich diet is necessary for proper thyroid gland function. Subclinical hypothyroidism (SCH) is associated with serious complications. Substantial numbers of patients have risk of SCH getting converted into primary hypothyroidism.Objectives:The objectives of the present study are to survey dietary iodine intake pattern in ethnic population of Kashmir and to study the prevalence of SCH.Materials and Methods:A retrospective, cross-sectional referral hospital study was conducted. Sample size comprised of 2550 patients who were referred to Department of Biochemistry, Government Medical college, Srinagar diagnostic laboratory from OPD and IPD of associated SMHS hospital. Assessment of thyroid function over a period of one year from March 2010 to March 2011 in the serum has been performed by electro-chemiluminescence immunoassay method on ECLIA 2010 fully automatic analyzer. Interview cum questionnaire methods were used to record the patient history and dietary iodine intake pattern. Iodine status of these patients was assessed by measuring urinary iodine excretion.Results:Total patients were 2550 comprising of 44.6% males and 56.4% females. Subjects with elevated and normal thyroid stimulating hormone (TSH) levels in the serum were 30.51 and 69.4% respectively. About 550 patients (21.56%) had subclinical hypothyroidism which includes both males and females. Prevalence of SCH was more in females (81.8%) than in males (18.2%). Most of the patients presenting with SCH were in the age group of 20–65 years.Conclusion:The percentage of SCH amongst the study sample patients was 21.56%, which is much higher as compared to other parts of the world. The highest percentage of SCH was found in females (81.8%) as compared to males (18.2%). On the basis of the present study, we suggest that routine screening of selected populations, especially women between 20 and 65 years of age, may be advocated. Further community level awareness programs need to be organized wherein people in mountainous valley of Kashmir are motivated to take salt in iodized form and diet rich in iodine to ensure proper thyroid gland functioning.

Effects of thyroxine replacement on endothelial function and carotid artery intima-media thickness in female patients with mild subclinical hypothyroidism

BACKGROUND:Previous studies have suggested an association between subclinical hypothyroidism and coronary artery disease that could be related to changes in serum lipids or endothelial dysfunction.METHODS:Thirty-two female subclinical hypothyroidism patients were randomly assigned to 12 months of L-thyroxine replacement or no treatment. Endothelial function was measured by the flow-mediated vasodilatation of the brachial artery, as well as mean carotid artery intima-media thickness, and lipid profiles were studied at baseline and after 12 months of follow-up.RESULTS:The mean (±SD) serum thyroid-stimulating hormone levels in the L-thyroxine replacement and control groups were 6.09±1.32 and 6.27±1.39 µUI/ml, respectively. No relationship between carotid artery intima-media thickness or brachial flow-mediated vasodilatation and free T4 and serum thyroid-stimulating hormone was found. The median L-T4 dose was 44.23±18.13 µg/day. After 12 months, there was a significant decrease in the flow-mediated vasodilatation in the subclinical hypothyroidism control group (before: 17.33±7.88 to after: 13.1±4.75%, p = 0.03), but there were no significant differences in flow-mediated vasodilatation in the L-thyroxine treated group (before: 16.81±7.0 to after: 18.52±7.44%, p = 0.39). We did not find any significant change in mean carotid intima-media thickness after 12 months of L-thyroxine treatment.CONCLUSION:Replacement therapy prevents a decline in flow-mediated vasodilatation with continuation of the subclinical hypothyroidism state. Large prospective multicenter placebo-controlled trials are necessary to investigate endothelial physiology further in subclinical hypothyroidism patients and to define the role of L-thyroxine therapy in improving endothelial function in these patients.

Decrease of brachial-ankle pulse wave velocity in female subclinical hypothyroid patients during normalization of thyroid function: a double-blind, placebo-controlled study

Subclinical hypothyroidism affects 5-15% of the general population, is especially prevalent in females, and may be associated with increased morbidity from cardiovascular disease, although it remains controversial. We recently reported a significant increase in the brachial-ankle pulse wave velocity (baPWV), a parameter of arterial stiffening and an independent predictor of cardiovascular events, in subclinical hypothyroidism without thyroiditis. The current study was performed to assess changes in baPWV in female subclinical hypothyroidism with autoimmune chronic thyroiditis (Hashimoto's disease) after restoration of normal thyroid function. In a randomized placebo-controlled study, 95 female subclinical hypothyroid patients were monitored for changes in baPWV before and after levothyroxine (l-T(4)) replacement therapy. Changes in baPWV were also measured in 42 age-matched normal female subjects. The baseline baPWV values in patients with subclinical hypothyroidism were significantly higher than in normal subjects. With attainment of euthyroidism, baPWV showed a significant decrease from 1776.7+/-86.0 to 1674.3+/-79.2 cm/s (P=0.006) in patients treated with l-T(4), but the changes in baPWV and TSH were not correlated. The change in baPWV was significantly and negatively correlated with age and baseline pulse pressure, but multiple regression analysis revealed that these parameters failed to be associated with the change in baPWV. Sustained normalization of thyroid function during l-T(4) replacement therapy significantly decreases baPWV in female subclinical hypothyroid patients with autoimmune chronic thyroiditis, suggesting the improvement of arterial stiffening and, consequently, possible prevention of cardiovascular disease.

Frequency of Abnormal Thyroid Function Tests in Kuwaiti Arabs with Autoimmune Diseases

Objectives: The purpose of this study was to examine the frequencies of abnormal thyroid function tests and serum thyroid autoantibodies in healthy Kuwaitis and those with autoimmune diseases. Subjects and Methods: Serum concentrations of sensitive thyrotropin, and free thyroxine were measured in 577 apparently healthy controls, 177 patients with rheumatoid arthritis (RA), 60 with systemic lupus erythematosus (SLE) and 25 with primary Sjogren’s syndrome (pSS) using the immunochemiluminescent assay method on IMMULITE 1000. Serum microsomal and thyroglobulin autoantibodies were also measured by passive hemagglutination assay. For analysis of the thyroid function tests, the subjects were classified into five categories: normal, subclinical hypothyroidism, overt hypothyroidism, euthyroid sick syndrome and biochemical hyperthyroidism. Results: Subclinical hypothyroidism was seen in 1.7% of healthy controls, 10.2% of RA, 13.3% of SLE, and 16% of pSS patients. Among RA patients, the frequency of subclinical hypothyroidism in females (11.4%) was significantly higher than among males (5.4%; p < 0.01). In SLE and pSS patients, all those with subclinical hypothyroidism were females. Overt hypothyroidism was seen in 1.4% of controls, 10.2% of RA, 8.3% of SLE, and 4% of pSS patients. Biochemical hyperthyroidism was seen in 0.2% of controls, 4.5% of RA, 5% of SLE and none of pSS patients. The euthyroid sick syndrome was seen in 0.4% of controls, 13.6% of RA, 16.7% of SLE and in none of pSS patients. Thyroid autoantibodies were present in 3.1% of controls, 12.4% of RA, 18.3% of SLE, and 12% of pSS patients. Conclusion: Our data show that abnormal thyroid function tests and thyroid autoantibodies occur frequently in Ku-waitis with autoimmune diseases. Therefore, ordering these tests in these diseases is recommended.