Thyroid-stimulating hormone (TSH) level in nutritionally obese children and metabolic co-morbidity

Association of high BMI with subclinical hypothyroidism in young, first-episode and drug-naïve patients with major depressive disorder: a large-scale cross-sectional study

Thyroid dysfunction is known to be associated with obesity, but the reliability of this relationship is easily affected by drug treatment, age, and subclinical hypothyroidism (SCH) with no apparent symptoms. Our research aims to compare obese and overweight BMI ranges with SCH and without SCH in a large sample of young, first-episode and drug-naïve (FEDN) patients with major depressive disorder (MDD), which has received little systemic investigation. A total of 1289 FEDN MDD young outpatients were recruited for this study. Serum thyroid function and lipid level parameters were measured; HAMD and PANSS scales were used to assess patients' depression and positive symptoms. A self-administered questionnaire collected other clinical and demographic data. The prevalence of SCH in FEDN MDD young patients was 58.26%. Compared to patients without SCH, the patients with SCH had a more prolonged illness duration, higher BMI levels, increased prevalence of overweight and obesity, higher HAMD score and PANSS-positive symptom scores, higher levels of TG, TC, LDL-C, and lower levels of HDL-C. Further logistic regression indicated that overweight BMI, obese BMI, illness duration, HAMD score, HDL-C, and TC were significantly associated with SCH. Our results indicate that obesity and overweight may be associated with SCH in young, FEDN MDD patients. The importance of regular thyroid function assessment in young FEDN MDD patients with high BMI should be taken into account.

Body Composition and Cardiovascular Risk Factors in a Paediatric Population

The aim of our study was to evaluate associations between body composition parameters and several clinical parameters. A total of 206 children and adolescents (120 male, 86 female) were prospectively included. Body impedance measurement was performed in all participants. During the hospital work-up, several clinical parameters such as anthropometric measurements and laboratory and ultrasound findings were obtained and correlated to body composition parameters. There was a significant association between body composition parameters and anthropometric measurements, systolic blood pressure, insulin levels, serum creatinine, urate, liver function tests, triglycerides, cholesterols and apolipoproteins, homocysteine, vitamin D and proteins in 24-h urine. Body composition differed by gender, between participants with and without hepatic steatosis and between patients with and without left ventricular hypertrophy. Interestingly, body composition did not correlate with diastolic blood pressure, pulse wave velocity and intima media thickness. This study showed that several clinical parameters are associated with body composition in children. Obesity and body composition play an important role in the development of other cardiovascular risk factors and are not dependent on fat mass alone, and the latter might be used for cardiovascular risk determination.

Cardiovascular Risk Factors in Children with Obesity, Preventive Diagnostics and Possible Interventions

The increasing burden of obesity plays an essential role in increased cardiovascular morbidity and mortality. The effects of obesity on the cardiovascular system have also been demonstrated in childhood, where prevention is even more important. Obesity is associated with hormonal changes and vascular dysfunction, which eventually lead to hypertension, hyperinsulinemia, chronic kidney disease, dyslipidemia and cardiac dysfunction—all associated with increased cardiovascular risk, leading to potential cardiovascular events in early adulthood. Several preventive strategies are being implemented to reduce the cardiovascular burden in children. This paper presents a comprehensive review of obesity-associated cardiovascular morbidity with the preventive diagnostic workup at our hospital and possible interventions in children.

Establishing paediatric reference intervals for thyroid function tests in Croatian population on the Abbott Architect i2000

Introduction

Evaluation of thyroid function is often requested and therefore defining paediatric reference intervals (RIs) is of vital importance. Currently, there is a distinct lack of paediatric RIs for thyroid function tests in Croatia. Thus, we established RIs for thyroid stimulating hormone (TSH), total triiodothyronine (TT3), total thyroxine (TT4), free triiodothyronine (FT3) and free thyroxine (FT4) in the Croatian paediatric population.

Materials and methods

Reference intervals were calculated from 397 apparently healthy children, aged from 2 days to < 19 years. Serum samples were analysed for thyroid function tests on the Abbott Architect i2000. Age- and sex-specific 95% RIs with 90% confidence intervals were established according to Clinical and Laboratory Standards Institute guidelines. To express the magnitude of sex and age variation, standard deviation ratio (SDR) was calculated using two-level nested ANOVA. The criterion for considering partitioning reference values was set to SDR > 0.3.

Results

All thyroid function tests required age partitioning, confirmed by SDR above 0.3. There was no need for sex partitioning, confirmed by SDR below 0.3. Still, FT3 was partitioned due to visually noticeable sex related difference for the oldest group (12 years to < 19 years).

Conclusion

This is the first study to establish RIs for thyroid function tests in the Croatian paediatric population. We propose RIs for widely used Abbott platform, thus giving laboratories method- and population-specific paediatric RIs for thyroid function tests that should improve clinical test interpretation.

Environmental Factors Affecting Thyroid-Stimulating Hormone and Thyroid Hormone Levels

Thyroid hormones are necessary for the normal functioning of physiological systems. Therefore, knowledge of any factor (whether genetic, environmental or intrinsic) that alters the levels of thyroid-stimulating hormone (TSH) and thyroid hormones is crucial. Genetic factors contribute up to 65% of interindividual variations in TSH and thyroid hormone levels, but many environmental factors can also affect thyroid function. This review discusses studies that have analyzed the impact of environmental factors on TSH and thyroid hormone levels in healthy adults. We included lifestyle factors (smoking, alcohol consumption, diet and exercise) and pollutants (chemicals and heavy metals). Many inconsistencies in the results have been observed between studies, making it difficult to draw a general conclusion about how a particular environmental factor influences TSH and thyroid hormone levels. However, lifestyle factors that showed the clearest association with TSH and thyroid hormones were smoking, body mass index (BMI) and iodine (micronutrient taken from the diet). Smoking mainly led to a decrease in TSH levels and an increase in triiodothyronine (T3) and thyroxine (T4) levels, while BMI levels were positively correlated with TSH and free T3 levels. Excess iodine led to an increase in TSH levels and a decrease in thyroid hormone levels. Among the pollutants analyzed, most studies observed a decrease in thyroid hormone levels after exposure to perchlorate. Future studies should continue to analyze the impact of environmental factors on thyroid function as they could contribute to understanding the complex background of gene-environment interactions underlying the pathology of thyroid diseases.

Is Waist-height Ratio Associated with Thyroid Antibody Levels in Children with Obesity?

OBJECTIVE

Obesity is known to affect thyroid function. Recently, waist-height ratio (WHtR) has been considered as a useful marker of subclinical hypothyroidism in obese cases, but its relation with thyroid autoimmunity still remains unclear. We evaluated the effect of body fat mass, WHtR, and metabolic parameters on thyroid autoantibody levels in children with obesity.

METHODS

This was a cross-sectional study carried out with an obese [n=56, male/female (M/F): 29/26] and a healthy group (n=38, M/F: 19/19). All subjects underwent anthropometric measurements, laboratory investigations for thyroid function tests, thyroid peroxidase (TPO-ab) and thyroglobulin-antibodies (Tg-ab), transaminases, blood glucose, insulin levels, and lipids after overnight fasting; homeostatic model assessment for insulin resistance (HOMA-IR) was calculated for assessment of insulin resistance. Fat mass was estimated by multiple frequency bioimpedance analysis in the obese group, which was further divided into two subgroups according to the median of WHtR. All parameters were compared between the groups/subgroups.

RESULTS

In the obese group, weight, height, body mass index (BMI), free triiodothyronine, thyrotropin, TPO-ab, insulin, low density lipoprotein-cholesterol, total cholesterol, alanine aminotransferase levels, and HOMA-IR were significantly higher than the controls group (p<0.05 for all). Median of WHtR was 0.6 in the obese group. In the “WHtR >0.6” subgroup (n=28), weight, BMI, fat mass, TPO-ab, Tg-ab, insulin and triglyceride levels were higher than WHtR ≤0.6 subgroup (p<0.05). A positive correlation was obtained between Tg-ab and WHtR (rho=0.28, p=0.041).

CONCLUSION

Euthyroid children with obesity and a WHtR >0.6 are likely to have higher thyroid antibody levels, and Tg-ab levels have a positive correlation with WHtR, which reveals an association of central adiposity with thyroid autoantibody levels in these cases.

Adiponectin and Thyroid Cancer: Insight into the Association between Adiponectin and Obesity

In recent decades, the incidence and diagnosis of thyroid cancer have risen dramatically, and thyroid cancer has now become the most common endocrine cancer in the world. The onset of thyroid cancer is insidious, and its progression is slow and difficult to detect. Therefore, early prevention and treatment have important strategic significance. Moreover, an in-depth exploration of the pathogenesis of thyroid cancer is key to early prevention and treatment. Substantial evidence supports obesity as an independent risk factor for thyroid cancer. Adipose tissue dysfunction in the obese state is accompanied by dysregulation of a variety of adipocytokines. Adiponectin (APN) is one of the most pivotal adipocytokines, and its connection with obesity and obesity-related disease has gradually become a hot topic in research. Recently, the association between APN and thyroid cancer has received increasing attention. The purpose of this review is to systematically review previous studies, give prominence to APN, focus on the relationship between APN, obesity and thyroid cancer, and uncover the underlying pathogenic mechanisms.

Relationship of TSH Levels with Cardiometabolic Risk Factors in US Youth and Reference Percentiles for Thyroid Function

CONTEXT

Thyroid hormones play an important role in metabolic homeostasis, and higher levels have been associated with cardiometabolic risk.

OBJECTIVE

To examine the association of cardiometabolic risk factors with TSH levels in US youth.

METHODS

Cross-sectional study of youth aged 12 to 18 years without known thyroid abnormalities from 5 National Health and Nutrition Examination Survey cycles (n = 2818) representing 15.4 million US children. Subclinical hypothyroidism (SH) was defined as thyrotropin (TSH) levels of 4.5 to 10 mIU/L. Assessed cardiometabolic risk factors include abdominal obesity (waist circumference >90th percentile), hypertriglyceridemia (triglyceride ≥130 mg/dL), low high-density lipoprotein cholesterol (<40 mg/dL), elevated blood pressure (systolic and diastolic blood pressure ≥90th percentile), hyperglycemia (fasting blood glucose ≥100 mg/dL, or known diabetes), insulin resistance (homeostatic model for insulin resistance > 3.16), and elevated alanine transferase (≥ 50 for boys and ≥44 U/L for girls). Age and sex- specific percentiles for thyroid parameters were calculated.

RESULTS

In this cohort of youth (51.3% male), 31.2% had overweight/obesity. The prevalence of SH was 2.0% (95% CI 1.2-3.1). The median TSH levels were higher in youth with overweight/obesity (P < 0.001). Adjusting for age, sex, race/ethnicity, and obesity, youth with TSH in the fourth quantile had higher odds of abdominal obesity (OR 2.53 [1.43-4.46], P = .002), insulin resistance (OR 2.82 [1.42-5.57], P = .003), and ≥2 cardiometabolic risk factors (CMRF) (OR 2.20 [1.23-3.95], P = .009).

CONCLUSION

The prevalence of SH is low in US youth. The higher odds of insulin resistance and cardiometabolic risk factors in youth with TSH levels >75th percentile requires further study.

Effect of TSH on Non-Alcoholic Fatty Liver Disease (NAFLD) independent of obesity in children of predominantly Hispanic/Latino ancestry by causal mediation analysis

Background

Nonalcoholic Fatty Liver Disease (NAFLD) is a common co-morbidity of obesity. Elevated TSH levels (eTSH), also associated with obesity, may contribute to the dysmetabolic state that predisposes to NAFLD.

Objective

To assess the relationship between TSH levels and NAFLD in children with biopsy-proven NAFLD compared to controls.

Design and methods

In this retrospective study of children with biopsy-proven NAFLD and age-matched controls, the association of eTSH with NAFLD was investigated and the role of TSH as a mediator between obesity and NAFLD was assessed.

Results

Sixty-six cases and 4067 controls (69.7 vs 59% Hispanic/Latino ancestry, p = 0.1) of the same age range seen in the same time duration at an urban Children’s Hospital were studied. Children with NAFLD were more likely to be male (74.6 vs 39.4%, p < 0.001), have higher modified BMI-z scores (median 2.4 (IQR 1.7) vs 1.9 (IQR 1.7), p < 0.001), and abnormal metabolic parameters (TSH, ALT, HDL-C, non-HDL-C, and TG). Multivariate analyses controlling for age, sex and severity of obesity showed significant association between the 4^th quartile of TSH and NAFLD. Causal mediation analysis demonstrates that TSH mediates 33.8% of the effect of modified BMI-z score on NAFLD. This comprises of 16.0% (OR = 1.1, p = 0.002) caused by the indirect effect of TSH and its interaction with modified BMI-z, and 17.7% (OR = 1.1, p = 0.05) as an autonomous effect of TSH on NAFLD. Overall, 33.8% of the effect can be eliminated by removing the mediator, TSH (p = 0.001).

Conclusions

The association of eTSH and biopsy-proven NAFLD is demonstrated in children of Hispanic/Latino ancestry. Further, a causal mediation analysis implicates an effect of TSH on NAFLD, independent of obesity.

Influence of subclinical hypothyroidism on metabolic parameters in obese children and adolescents

BACKGROUND

Subclinical hypothyroidism (SH) is a common condition in obese children. However, its effect on glucose and lipid metabolism in obese children remains controversial.

PURPOSE

The present study aimed to investigate the association between SH and metabolic parameters.

METHODS

A total of 215 obese children and adolescents aged 6-18 years were included in this retrospective cross-sectional study. The patients' anthropometric measurements such as thyrotropin (TSH), free thyroxine (fT4), fasting plasma glucose, and insulin levels, as well as homeostasis model assessment for insulin resistance (HOMA-IR) index, and lipid profiles were evaluated. The patients were allocated to the SH group (fT4 normal, TSH 5-10 mIU/L) (n=77) or the control group (fT4 normal, TSH<5 mIU/L) (n=138). The glucose and lipid metabolisms of the 2 groups were compared.

RESULTS

SH was identified in 77 of 215 patients (36%). Mean body mass index was similar in both groups. The mean serum insulin, HOMA-IR, and triglyceride (TG) levels were higher and the mean high-density lipoprotein cholesterol level was lower in the SH group than in the control group (P=0.007, P=0.004, P=0.01, and P=0.02, respectively). A positive correlation was observed between TSH level and insulin level, HOMA-IR, and TG level.

CONCLUSION

SH was identified in some of the obese children and adolescents. A clear association was observed between SH, insulin resistance, and dyslipidemia in obese children.

Effects of thyroid hormone and depression on common components of central obesity

Objective

We investigated the prevalence of abnormal thyroid function and depression in centrally obese participants, and to analyze the relationship of thyroid hormones and depression with components of central obesity.

Methods

We randomly selected 858 centrally obese participants and 500 non-obese controls in this study. For all participants, we measured serum free triiodothyronine (FT3), free thyroxine (FT4), thyroid-stimulating hormone (TSH), body mass index (BMI), waist–hip ratio (WHR), fasting blood glucose and insulin, homeostasis model assessment of insulin resistance (HOMA-IR), lipid concentrations, and blood pressure. Depression was assessed using the Center for Epidemiological Studies-Depression (CES-D) scale.

Results

Centrally obese participants had a higher prevalence of hypothyroidism and depression than non-obese controls. Serum FT4 levels negatively correlated with BMI and serum TSH levels and positively correlated with BMI, WHR, total triglycerides (TG), total cholesterol (TC), and low density lipoprotein cholesterol (LDL-C). After excluding participants with hypothyroidism and hyperthyroidism, serum FT4 levels showed negative correlation and serum TSH levels showed positive correlation with BMI in the remaining centrally obese participants. CES-D scores positively correlated with BMI.

Conclusion

We found high prevalences of hypothyroidism and depression among centrally obese participants. FT4 and TSH are important in weight regulation. Depression positively correlated with obesity.

Reference values for fasting serum concentrations of thyroid-stimulating hormone and thyroid hormones in healthy Danish/North-European white children and adolescents

Thyroid-stimulating hormone (TSH) and thyroid hormones influence the functions of many organ systems, as well as child development and growth. Several studies have reported an association between ethnicity and thyroid hormones. This study aims to explore pediatric serum concentrations of TSH, free triiodothyronine (fT3), and free thyroxine (fT4) and their relation to age and sex and subsequently to present pediatric reference intervals from healthy Danish/North-European white children. A population-based cohort in Denmark of 2411 (1435 girls) healthy school children and adolescents aged 6.0-18.9 years were included. Fasting concentrations of serum TSH, fT3, and fT4 were determined from venous blood samples using immunologic chemiluminescent assays. Age- and sex-dependent percentiles were generated using the GAMLSS function. Median values of fT3 and fT4, but not TSH, were lower in the older age group compared with the youngest age group for both sexes (all p < .05). A significant difference for fT3 was found between the sexes for all age groups (all p < .001). fT4 was negatively correlated with body mass index standard deviation scores in boys. In conclusion, serum concentrations of thyroid hormones vary during childhood and adolescence and differ with age and sex.

Childhood thyroid function, body composition and cardiovascular function

OBJECTIVE

The cardiovascular system is a known target for thyroid hormone. Early-life cardiovascular alterations may lead to a higher risk of cardiovascular disease in adulthood. Little is known about the effects of thyroid hormone on cardiovascular function during childhood, including the role of body composition in this association.

DESIGN

Population-based prospective cohort of children (n = 4251, median age 6 years, 95% range: 5.7-8.0 years).

METHODS

Thyroid-stimulating hormone (TSH) and free thyroxine (FT4) concentrations were measured to assess thyroid function. Left ventricular (LV) mass was assessed with echocardiography. Arterial stiffness was assessed with carotid-femoral pulse wave velocity (CFPWV). Systolic and diastolic blood pressure (BP) was measured. Body composition was assessed by dual-energy X-ray absorptiometry scan.

RESULTS

FT4 was inversely associated with LV mass (P = 0.002), and with lean body mass (P < 0.0001). The association of FT4 with LV mass was partially mediated through variability in lean body mass (55% mediated effect). TSH was inversely associated with LV mass (P = 0.010), predominantly in boys. TSH was positively associated with systolic and diastolic BP (both P < 0.001). FT4 was positively associated with CFPWV and diastolic BP (P < 0.0001, P = 0.008, respectively), and the latter association attenuated after adjustment for CFPWV.

CONCLUSIONS

At the age of 6 years, higher FT4 is associated with lower LV mass (partially through effects on lean body mass) and with higher arterial stiffness, which may lead to higher BP. Our data also suggest different mechanisms via which TSH and FT4 are associated with cardiovascular function during early childhood.

MMP-9 Levels and IMT of Carotid Arteries are Elevated in Obese Children and Adolescents Compared to Non-Obese

BACKGROUND

Childhood obesity is associated with increased risk of atherosclerosis and cardiovascular disease in adulthood. Increased intima-media thickness (IMT) of the carotid artery is linked to the initiation and progression of the chronic inflammatory processes implicated in cardiovascular disease. Matrix metalloproteinase-9 (MMP-9) plays an important role in the degradation of the extracellular matrix and, consequently, in the development, morphogenesis, repair and remodeling of connective tissues.

OBJECTIVES

(i) to determine and compare the concentrations of MMP-9, tissue inhibitor of metalloproteinase -1 (TIMP-1), and MMP-9/TIMP-1 ratio in obese and non-obese children and adolescents; (ii) to investigate the association of these markers with common and internal IMT of carotid arteries.

METHODS

Cross-sectional study involving 32 obese and 32 non-obese (control) individuals between 8 - 18 years of age.

RESULTS

Significantly (p < 0.05) higher values of MMP-9 concentration, as well as a higher MMP-9/TIMP-1 ratio were detected in the obese group compared to control counterparts. Common and internal carotid IMT values were significantly higher (p < 0.001) in the obese group compared to the control group. Positive correlations were observed between the common carotid IMT values and MMP-9 concentrations as well as MMP-9/TIMP-1 ratio.

CONCLUSIONS

Our data demonstrate that obese children and adolescents present higher mean IMT values, plasma MMP-9 and MMP-9/TIMP-1 ratio compared to the non-obese. Thus, these findings indicate that this group presents a risk profile for early atherosclerosis.

Atopy as a risk factor for subclinical hypothyroidism development in children

BACKGROUND

Increased thyroid stimulating hormone (TSH) serum concentration can be a marker of subclinical hypothyroidism (SCH) or transient hyperthyrotropinemia. The aim of our study was to evaluate whether high serum TSH concentrations in allergic children could represent true SCH or isolated and transient hyperthyrotropinemia.

METHODS

We enrolled 620 allergic children (1.11-12.8 years) consecutively attending to our department. They were classified as atopics and non-atopics on the basis of the atopy work-up and, at baseline, they were investigated for thyroid function and low-grade inflammation state. Further, TSH was evaluated after 6 (T1) and 12 (T2) months.

RESULTS

Both atopics and non-atopics showed higher SCH prevalence compared to controls (p=0.0055 and p=0.02, respectively), and a significant association between atopy and SCH (OR 10.11, 95% CI 1.36-75.12) was found. Both at T1 and T2, atopics had a significant risk of developing severe SCH compared to non-atopics (RR 1.8, 95% CI 1.39-2.34 and 1.61, 95% CI 1.21-2.14; respectively).

CONCLUSIONS

Our data may suggest that hyperthyrotropinemia in atopic children could be used as a marker of true SCH.

A genome-wide association study of thyroid stimulating hormone and free thyroxine in Danish children and adolescents

Background

Hypothyroidism is associated with obesity, and thyroid hormones are involved in the regulation of body composition, including fat mass. Genome-wide association studies (GWAS) in adults have identified 19 and 6 loci associated with plasma concentrations of thyroid stimulating hormone (TSH) and free thyroxine (fT4), respectively.

Objective

This study aimed to identify and characterize genetic variants associated with circulating TSH and fT4 in Danish children and adolescents and to examine whether these variants associate with obesity.

Methods

Genome-wide association analyses of imputed genotype data with fasting plasma concentrations of TSH and fT4 from a population-based sample of Danish children, adolescents, and young adults, and a group of children, adolescents, and young adults with overweight and obesity were performed (N = 1,764, mean age = 12.0 years [range 2.5−24.7]). Replication was performed in additional comparable samples (N = 2,097, mean age = 11.8 years [1.2−22.8]). Meta-analyses, using linear additive fixed-effect models, were performed on the results of the discovery and replication analyses.

Results

No novel loci associated with TSH or fT4 were identified. Four loci previously associated with TSH in adults were confirmed in this study population (PDE10A (rs2983511: β = 0.112SD, p = 4.8 ∙ 10⁻¹⁶), FOXE1 (rs7847663: β = 0.223SD, p = 1.5 ∙ 10⁻²⁰), NR3C2 (rs9968300: β = 0.194SD), p = 2.4 ∙ 10⁻¹¹), VEGFA (rs2396083: β = 0.088SD, p = 2.2 ∙ 10⁻¹⁰)). Effect sizes of variants known to associate with TSH or fT4 in adults showed a similar direction of effect in our cohort of children and adolescents, 11 of which were associated with TSH or fT4 in our study (p<0.0002). None of the TSH or fT4 associated SNPs were associated with obesity in our cohort, indicating no pleiotropic effects of these variants on obesity.

Conclusion

In a group of Danish children and adolescents, four loci previously associated with plasma TSH concentrations in adults, were associated with plasma TSH concentrations in children, suggesting comparable genetic determinants of thyroid function in adults and children.

Subclinical Hypothyroidism in Danish Lean and Obese Children and Adolescents

OBJECTIVE

Thyroid abnormalities are common in obese children. The aim of the present study was to examine the prevalence of subclinical hypothyroidism (SH) and to determine how circulating thyroid hormone concentrations correlate with anthropometrics in Danish lean and obese children and adolescents.

METHODS

In this cross-sectional study, we included 3006 children and adolescents, aged 6-18 years, from the Registry of the Danish Childhood Obesity Biobank. The overweight/obese group (n=1796) consisted of study participants with a body mass index (BMI) standard deviation score (SDS) ≥1.28. The control group (n=1210) comprised lean children with a BMI SDS <1.28. All participants were characterized by anthropometrics (weight, height, and waist circumference) and fasting serum concentrations of thyroid-stimulating hormone (TSH), free triiodothyronine, and free thyroxine (fT4) at baseline.

RESULTS

The prevalence of SH was higher among overweight/obese compared to lean study participants (10.4% vs. 6.4%, p=0.0001). In the overweight/obese group, fasting serum TSH concentrations were associated positively with BMI SDS (p<0.0001) and waist-height ratio (WHtR) (p<0.0001) independent of age, sex, and pubertal developmental stage, whereas fasting serum fT4 concentrations were associated positively only with WHtR. The odds ratio of exhibiting SH was 1.8 when being overweight/obese compared with lean (p=0.0007) and 1.8 when presenting with a WHtR >0.5 (p=0.0003).

CONCLUSION

The prevalence of SH was higher among overweight/obese study participants. The positive correlations of circulating TSH and fT4 with WHtR suggest that central obesity, independent of the overall degree of obesity, augments the risk of concurrent thyroid abnormalities in children and adolescents with obesity.

The effects of antipsychotics on weight gain, weight-related hormones and homocysteine in children and adolescents: a 1-year follow-up study

To analyze weight gain, metabolic hormones, and homocysteine (Hcys) levels in children and adolescents on antipsychotics (AP) during a year-long follow-up. 117 patients, AP-naïve or quasi-naïve (less than 30 days on AP), were included. Weight, body mass index (BMI), BMI z-score (z-BMI), and levels of leptin, insulin, insulin resistance (HOMA-IR), adiponectin, ghrelin, thyroid stimulating hormone (TSH), free thyroxine (FT4), and Hcys were measured at baseline, and at 3, 6, and 12 months, while patients remained on the same AP. Patients (mean age: 14.4 ± 3 years; 64.1 % male) were on risperidone (N = 84), olanzapine (N = 20) or quetiapine (N = 13) from baseline up to 1-year follow-up and significantly increased weight (5.8 ± 4.3 kg at 3-month, 8.1 ± 6.1 kg at 6-month, and 11.6 ± 7.0 kg at 1 year), BMI, and z-BMI. Leptin levels significantly increased from baseline to 3 and 6 months, as did TSH levels from baseline to 3 months, while FT4 levels decreased from baseline to 3 and 6 months. Patients with BMI >85th percentile at baseline (N = 16) significantly increased weight, BMI, and z-BMI, more than patients with normal BMI over time. Higher baseline levels of insulin, HOMA-IR, and leptin were associated with increased weight/BMI during follow-up, while higher baseline levels of FT4, adiponectin, and ghrelin were associated with lower weight/BMI during follow-up. All AP were associated with increased weight and BMI/z-BMI in all of the assessments; however, at 1-year assessment, this increase was significantly higher for patients on quetiapine. Both higher baseline levels of insulin, HOMA-IR, and leptin, as well as being overweight/obese at baseline were associated with increased weight/BMI during 1-year follow-up in children and adolescents on AP. Awareness of weight-related parameters in this population may help inform decisions regarding AP prescriptions.

Serum TSH levels are associated with cardiovascular risk factors in overweight and obese adolescents

OBJECTIVE

To investigate the relationship between serum thyrotropin (TSH), insulin resistance (IR), and cardiovascular risk factors (CRF) in a sample of overweight and obese Brazilian adolescents.

METHODS

A retrospective, longitudinal analysis of 199 overweight and obese pubescent adolescents was performed. The TSH and free T4 (fT4) levels, anthropometric measurements, and laboratory test results of these patients were analyzed.

RESULTS

27 individuals (13.56%) presented with TSH levels above the normal level (subclinical hypothyroidism [SCH]). Their waist circumference (WC) was significantly higher than those of euthyroid individuals. Serum TSH was positively correlated with the homeostasis model assessment of insulin resistance (HOMA-IR) index, triglycerides (TG) and high-density lipoprotein cholesterol (HDL-C). Using TSH and BMI as independent variables, TSH levels were shown to be independently related to HOMA-IR (p=0.001) and TG (p=0.007). Among euthyroid subjects, individuals with TSH values <2.5mIU/mL exhibited statistically significant decreases in waist-to-hip ratio, HDL-C levels, and HOMA-IR scores and a tendency toward lower WC values.

CONCLUSION

SCH in overweight and obese adolescents appears to be associated with excess weight, especially visceral weight. In euthyroid adolescents, there appears to be a direct relationship between TSH and some CRF. In conclusion, in the present sample of overweight and obese adolescents, TSH levels appear to be associated with IR and CRF.

Absence of a relationship between thyroid hormones and vitamin D levels

BACKGROUND

Vitamin D is an immune modulator that may play a role in thyroid related autoimmunity.

METHODS

We analyzed a US population based dataset to determine the relationship between serum 25-hydroxyvitamin D (25OHD) and thyroid hormones while assessing the effects of autoimmunity and BMI.

RESULTS

25OHD did not correlate significantly with any thyroid related measure. 25OHD levels stratified by thyroid antibody status were not statistically different between antibody positive and negative groups. The mean 25OHD levels of lean, overweight, and obese groups defined by BMI were lower than those of the normal group. Only the mean thyroid stimulating hormone (TSH) value in the obese group was significantly higher than the normal group.

CONCLUSIONS

We conclude that thyroid related measures and 25OHD serum levels are not related.

The association of thyroid hormones and blood pressure in euthyroid preadolescents

BACKGROUND

Hypertension is the leading cause of cardiovascular disease worldwide, and both high and low blood pressures are associated with various chronic diseases. Thyroid hormones have profound effects on cardiovascular function, including on blood pressure. Recent studies have shown that childhood hypertension can lead to adult hypertension. Therefore, adequate blood pressure control is important from early life. Employing a life-course approach, we aimed to investigate the association between thyroid hormones and blood pressure in children.

METHODS

A total of 290 children from the Ewha Woman's University Hospital birth cohort participated in a preadolescent check-up program. We assessed the levels of serum thyroid-stimulating hormone (TSH) and free thyroxine (FT4) and the blood pressure status in these children. Thyroid hormone concentrations were measured using an electro-chemiluminescence immunoassay (ECLIA), and hypertension was defined according to the guideline of the Korea Centers for Disease Control and Prevention.

RESULTS

The sex-, age-, and height-adjusted prevalence of hypertension was 27.0% in the present study. On regression analysis, serum FT4 showed significantly negative association with diastolic blood pressure (DBP; β=-8.24, 95% CI: -14.19-2.28, p=0.007). However, these relationships were not significant after adjustment for sex, age, and current body mass index. The levels of serum TSH showed no relationship with mean systolic blood pressure (SBP) and diastolic blood pressure (DBP) after adjustment. No significant differences in serum TSH and FT4 levels according to hypertension status were found.

CONCLUSIONS

These findings suggest that thyroid hormone is not independently associated with increased blood pressure in euthyroid preadolescents.

High-Cholesterol Diet Disrupts the Levels of Hormones Derived from Anterior Pituitary Basophilic Cells

Emerging evidence shows that elevated cholesterol levels are detrimental to health. However, it is unclear whether there is an association between cholesterol and the pituitary. We investigated the effects of a high-cholesterol diet on pituitary hormones using in vivo animal studies and an epidemiological study. In the animal experiments, rats were fed a high-cholesterol or control diet for 28 weeks. In rats fed the high-cholesterol diet, serum levels of thyroid-stimulating hormone (TSH; also known as thyrotrophin), luteinising hormone (LH) and follicle-stimulating hormone (FSH) produced by the basophilic cells of the anterior pituitary were elevated in a time-dependent manner. Among these hormones, TSH was the first to undergo a significant change, whereas adrenocorticotrophic hormone (ACTH), another hormone produced by basophilic cells, was not changed significantly. As the duration of cholesterol feeding increased, cholesterol deposition increased gradually in the pituitary. Histologically, basophilic cells, and especially thyrotrophs and gonadotrophs, showed an obvious increase in cell area, as well as a potential increase in their proportion of total pituitary cells. Expression of the β-subunit of TSH, FSH and LH, which controls hormone specificity and activity, exhibited a corresponding increase. In the epidemiological study, we found a similar elevation of serum TSH, LH and FSH and a decrease in ACTH in patients with hypercholesterolaemia. Significant positive correlations existed between serum total cholesterol and TSH, FSH or LH, even after adjusting for confounding factors. Taken together, the results of the present study suggest that the high-cholesterol diet affected the levels of hormones derived from anterior pituitary basophilic cells. This phenomenon might contribute to the pituitary functional disturbances described in hypercholesterolaemia.

Thyroid hormonal status among children with obesity

BACKGROUND

It is presumed that free T4 and thyroid-stimulating hormone (TSH) levels are related to obesity, but the findings are inconsistent. In this study we evaluated T4 and TSH concentrations between normal children and those with obesity and possible correlations between body mass index (BMI) and these markers.

METHODS

In this prospective study, 190 children who were overweight and obese and 133 children without obesity of the same age and sex were evaluated. Thyroid function tests (TSH, total T4, free T4 and free T3) were measured in all subjects in both groups. Thyroid antibodies (thyroid peroxidase and thyroglobulin) were determined among those with elevated TSH levels.

RESULTS

Levels of TSH and total T4 were significantly higher in children with obesity compared with the control group. Subclinical hypothyroidism was significantly higher in children with obesity (14.7%) compared with normal subjects (6.8%, p = 0.02). Among children with obesity and increased TSH levels, 10.7% had positive thyroid peroxidase and thyroglobulin antibodies. There was significantly positive correlation between BMI z score and TSH level (r = 0.198, p < 0.001) and T4 level (r = 0.18, p = 0.001).

CONCLUSION

TSH and total T4 levels are increased in children who are overweight or obese and are a common finding in these children, but the incidence of thyroid antibodies is low in these patients and so could not be accounted for by thyroid autoimmunity. Due to these findings it is possible that increased TSH and total T4 levels are a consequence of obesity and could be reduced by decreasing BMI.

Thyroid function is associated with insulin resistance markers in healthy adolescents with risk factors to develop diabetes

INTRODUCTION

The prevalence of obesity and Type 2 diabetes mellitus (T2DM) among children and adolescents is rising. Thyroid function has been associated with insulin resistance. There is scarce information about how thyroid function could be related with cardiovascular risk or glucose homeostasis in adolescent.

AIM

To analyze how thyroid function is associated with insulin resistance and another cardiovascular risk factors in healthy adolescents with risk factors to develop diabetes.

METHODS

A prospective cross-sectional analysis was carried out on euthyroid, adolescents. considered at high risk to develop Type 2 diabetes. Fasting blood samples were obtained. Thyroid function test and another cardiometabolic parameters were assessed. A 75 grams oral glucose tolerance test was performed to calculate insulin resistance.

RESULTS

One hundred adolescents were evaluated. The mean age was 15.9 ± 0.8 years, There is a negative correlation between Fasting insulin, post glucose load insulin and HOMA IR. There were no correlation with Matsuda index. We could not found any correlation with TSH values.

CONCLUSIONS

We found a correlation between fasting insulin, HOMA IR and serum thyroid hormones, we did not find any relation with serum TSH. In euthyroid adolescents with risk factors to develop diabetes.

Isolated hyperthyrotropinemia in childhood obesity and its relation with metabolic parameters

PURPOSE

The aim of the presented study was to evaluate the prevalence of isolated hyperthyrotropinemia (IH) in obese children and the relation between anthropometric and metabolic parameters.

METHODS

Hospital records of the children, who presented to the Pediatric Endocrinology outpatient clinic of our institution with obesity, and age and gender-matched healthy children, who had undergone thyroid function test for any reason were retrospectively reviewed.

RESULTS

The prevalence of IH was significantly higher in the obese group than in the controls (9.2 and 3.8 %, respectively). Body mass index-standard deviation score (BMI-SDS), thyroid-stimulating hormone (TSH), lipid parameters were significantly different in the obese group than in the control group. A positive correlation between TSH and BMI-SDS and negative correlation between TSH and free T4 (fT4) levels were found in obese subjects. Stepwise multiple linear regression analysis confirmed that BMI-SDS, fT4 and triglyceride levels were the strongest independent variables correlated with TSH level in obese subjects (r (2) = 0.046, p = 0.001).

CONCLUSIONS

IH prevalence is higher in obese children as compared to healthy children and the increase in TSH level correlates negatively with serum fT4 and positively with BMI-SDS and triglyceride levels in obese children.