Biol Trace Elem Res (2014) 157:95–100 DOI 10.1007/s12011-013-9880-8
Thyroid Functions and Trace Elements in Pediatric Patients with Exogenous Obesity Atilla Cayir & Hakan Doneray & Nezahat Kurt & Zerrin Orbak & Avni Kaya & Mehmet Ibrahim Turan & Abdulkadir Yildirim
Received: 11 December 2013 / Accepted: 19 December 2013 / Published online: 4 January 2014 # Springer Science+Business Media New York 2014
Abstract Obesity is a multifactorial disease developing following impairment of the energy balance. The endocrine system is known to be affected by the condition. Serum thyroid hormones and trace element levels have been shown to be affected in obese children. Changes in serum thyroid hormones may result from alterations occurring in serum trace element levels. The aim of this study was to evaluate whether or not changes in serum thyroid hormone levels in children with exogenous obesity are associated with changes in trace element levels. Eighty-five children diagnosed with exogenous obesity constituted the study group, and 24 age- and sexmatched healthy children made up the control group. Serum thyroid stimulating hormone (TSH), free thyroxine (fT4), free triiodothyronine (fT3), thyroglobulin (TG), selenium (Se), zinc (Zn), copper (Cu), and manganese (Mn) levels in the study group were measured before and at the third and sixth months of treatment, and once only in the control group. Pretreatment fT4 levels in the study group rose significantly by the sixth month (p=0.006). Zn levels in the patient group were significantly low compared to the control group (p= 0.009). Mn and Se levels in the obese children before and at the third and sixth months of treatment were significantly A. Cayir (*) Departments of Pediatric Endocrinology, Regional Training and Research Hospital, Erzurum, Turkey e-mail: [email protected] H. Doneray : Z. Orbak : A. Kaya Faculty of Medicine, Department of Pediatric Endocrinology Erzurum, Ataturk University, Erzurum, Turkey N. Kurt : A. Yildirim Faculty of Medicine, Department of Biochemistry Erzurum, Ataturk University, Erzurum, Turkey M. I. Turan Departments of Pediatrics, Regional Training and Research Hospital, Diyarbakir, Turkey
higher than those of the control group (p=0.001, p=0.001). In conclusion, fT4, Zn, Cu, Mn, and Se levels are significantly affected in children diagnosed with exogenous obesity. The change in serum fT4 levels is not associated with changes in trace element concentrations. Keywords Trace elements . Obesity . Thyroid functions test
Introduction As one of the most widespread endocrine disorders in the world, obesity compromises the endocrine system, in addition to the respiratory, cardiovascular, and gastrointestinal systems [1, 2]. Previous studies have examined the effect of obesity on thyroid functions. These have shown that obese patients have higher serum thyroid stimulating hormone (TSH) levels compared to nonobese subjects, and that the condition affects thyroid hormone levels to differing degrees [3–5]. Deficient intake of trace elements has been reported to be involved in the development of obesity [6–8]. Obese patients have been shown to have a low intake of iron (Fe) and zinc (Zn) in their diets [9]. Obese patients’ serum trace element levels are known to be affected [6, 8, 10]. A change in serum trace element concentrations can affect serum thyroid hormone levels [11–13]. One very recent study examining serum thyroid hormone levels and their association with trace elements in children receiving Na-valproate therapy determined a correlation between serum copper (Cu) levels and thyroid hormones [14]. Accordingly, changes in serum trace element concentrations in obese patients may also affect thyroid functions. The purpose of this study, the first of its kind in the literature, was to prospectively investigate the association between serum trace element levels and thyroid function in obese children.
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Materials and Methods The study was performed between February and August, 2012, at the Ataturk University Faculty of Medicine, Department of Child Health Endocrinology Clinic, Turkey. Local ethical committee approval was obtained before the study began. Patients were given detailed information about the aims of the study, and written consent forms were obtained. Patients with exogenous obesity and aged 5–18 were included in the study. Patients using products with special additives, with proven thyroid autoantibodies, with known thyroid disease or using drugs for thyroid disease were excluded. Healthy, age- and gender-matched children with thyroid hormones within normal limits were selected as the control group. Patients’ height and body weights were measured and recorded by the same individual. Height was measured using a wall-mounted stadiometer with children standing in bare feet. Body weight was measured with a weighing machine sensitive to 100 g with children wearing only underwear. Body mass indices (BMIs) and relative weights were calculated. Children were divided into three groups; overweight, obese, and morbidly obese. Initial triglyceride, cholesterol, HDL, low density lipoprotein (LDL), aspartate aminotransferase (AST), alanine aminotransferase (ALT), cortisol, ACTH, HbA1c, fT3, fT4, TSH, and TG levels were investigated from fasting venous blood specimens collected in the morning. All patients were given a diet list based on their ideal body weight. Additionally, at least 30 min aerobic exercise a day was recommended. Patients were monitored over 6 months. Weight was monitored at monthly checkups. Biochemical and hormonal measurements were repeated at the third- and sixth-month controls. Four-milliliter blood specimens were collected after 12-h fasting, once from the control group, and three times from the study group, at the start of the study and at the third and sixth months. Specimens were placed into biochemistry tubes, kept at room temperature for 10 min, and centrifuged for 5 min at 4500 rpm following complete coagulation. The serum specimens obtained were placed into special tubes and stored at −80ºC until assay. After being kept overnight at −20ºC, frozen serum samples were placed in a +4ºC environment. Zn, Cu, manganese (Mn), and selenium (Se) levels were measured from the thawed serum specimens. Biochemical Analyses For measurement of serum Zn and Cu levels, specimens were thinned with 0.2 % HNO3. Specimens were read on an AASflame-type unit using air-acetylene gas. For serum Mn measurement, specimens were thinned with 0.2 % HNO3 and read on an AAS-FIAS (hydride) unit using air-argon gas. For serum Se level measurement, all specimens were thinned with distilled water, and 500 μL diluted serum was mixed with
Cayir et al.
3 mL HClO4-HNO4 acid. The mixture was kept in a boiling water bath for 1 h and then left to cool. Next, 3 mL concentrated HCl was added. Specimens were kept in a boiling water bath for a further 1 h and left to cool. Distilled water was added to the cooled samples and 10 mL specimens obtained. These were then read on an AAS-FIAS (hydride) unit. Statistical Analysis The “Statistical Package for Social Sciences (SPSS) for Windows 20.0” program was used for statistical analysis. All analyzed parameters were presented as mean±SD. Distribution of parameters in the study and control groups was investigated prior to analysis. Student’s t test was used to analyze normally distributed parameters. Pearson’s correlation test was used for correlations. Significance was set at p
Thyroid Functions and Trace Elements in Pediatric Patients with Exogenous Obesity Atilla Cayir & Hakan Doneray & Nezahat Kurt & Zerrin Orbak & Avni Kaya & Mehmet Ibrahim Turan & Abdulkadir Yildirim
Received: 11 December 2013 / Accepted: 19 December 2013 / Published online: 4 January 2014 # Springer Science+Business Media New York 2014
Abstract Obesity is a multifactorial disease developing following impairment of the energy balance. The endocrine system is known to be affected by the condition. Serum thyroid hormones and trace element levels have been shown to be affected in obese children. Changes in serum thyroid hormones may result from alterations occurring in serum trace element levels. The aim of this study was to evaluate whether or not changes in serum thyroid hormone levels in children with exogenous obesity are associated with changes in trace element levels. Eighty-five children diagnosed with exogenous obesity constituted the study group, and 24 age- and sexmatched healthy children made up the control group. Serum thyroid stimulating hormone (TSH), free thyroxine (fT4), free triiodothyronine (fT3), thyroglobulin (TG), selenium (Se), zinc (Zn), copper (Cu), and manganese (Mn) levels in the study group were measured before and at the third and sixth months of treatment, and once only in the control group. Pretreatment fT4 levels in the study group rose significantly by the sixth month (p=0.006). Zn levels in the patient group were significantly low compared to the control group (p= 0.009). Mn and Se levels in the obese children before and at the third and sixth months of treatment were significantly A. Cayir (*) Departments of Pediatric Endocrinology, Regional Training and Research Hospital, Erzurum, Turkey e-mail: [email protected] H. Doneray : Z. Orbak : A. Kaya Faculty of Medicine, Department of Pediatric Endocrinology Erzurum, Ataturk University, Erzurum, Turkey N. Kurt : A. Yildirim Faculty of Medicine, Department of Biochemistry Erzurum, Ataturk University, Erzurum, Turkey M. I. Turan Departments of Pediatrics, Regional Training and Research Hospital, Diyarbakir, Turkey
higher than those of the control group (p=0.001, p=0.001). In conclusion, fT4, Zn, Cu, Mn, and Se levels are significantly affected in children diagnosed with exogenous obesity. The change in serum fT4 levels is not associated with changes in trace element concentrations. Keywords Trace elements . Obesity . Thyroid functions test
Introduction As one of the most widespread endocrine disorders in the world, obesity compromises the endocrine system, in addition to the respiratory, cardiovascular, and gastrointestinal systems [1, 2]. Previous studies have examined the effect of obesity on thyroid functions. These have shown that obese patients have higher serum thyroid stimulating hormone (TSH) levels compared to nonobese subjects, and that the condition affects thyroid hormone levels to differing degrees [3–5]. Deficient intake of trace elements has been reported to be involved in the development of obesity [6–8]. Obese patients have been shown to have a low intake of iron (Fe) and zinc (Zn) in their diets [9]. Obese patients’ serum trace element levels are known to be affected [6, 8, 10]. A change in serum trace element concentrations can affect serum thyroid hormone levels [11–13]. One very recent study examining serum thyroid hormone levels and their association with trace elements in children receiving Na-valproate therapy determined a correlation between serum copper (Cu) levels and thyroid hormones [14]. Accordingly, changes in serum trace element concentrations in obese patients may also affect thyroid functions. The purpose of this study, the first of its kind in the literature, was to prospectively investigate the association between serum trace element levels and thyroid function in obese children.
96
Materials and Methods The study was performed between February and August, 2012, at the Ataturk University Faculty of Medicine, Department of Child Health Endocrinology Clinic, Turkey. Local ethical committee approval was obtained before the study began. Patients were given detailed information about the aims of the study, and written consent forms were obtained. Patients with exogenous obesity and aged 5–18 were included in the study. Patients using products with special additives, with proven thyroid autoantibodies, with known thyroid disease or using drugs for thyroid disease were excluded. Healthy, age- and gender-matched children with thyroid hormones within normal limits were selected as the control group. Patients’ height and body weights were measured and recorded by the same individual. Height was measured using a wall-mounted stadiometer with children standing in bare feet. Body weight was measured with a weighing machine sensitive to 100 g with children wearing only underwear. Body mass indices (BMIs) and relative weights were calculated. Children were divided into three groups; overweight, obese, and morbidly obese. Initial triglyceride, cholesterol, HDL, low density lipoprotein (LDL), aspartate aminotransferase (AST), alanine aminotransferase (ALT), cortisol, ACTH, HbA1c, fT3, fT4, TSH, and TG levels were investigated from fasting venous blood specimens collected in the morning. All patients were given a diet list based on their ideal body weight. Additionally, at least 30 min aerobic exercise a day was recommended. Patients were monitored over 6 months. Weight was monitored at monthly checkups. Biochemical and hormonal measurements were repeated at the third- and sixth-month controls. Four-milliliter blood specimens were collected after 12-h fasting, once from the control group, and three times from the study group, at the start of the study and at the third and sixth months. Specimens were placed into biochemistry tubes, kept at room temperature for 10 min, and centrifuged for 5 min at 4500 rpm following complete coagulation. The serum specimens obtained were placed into special tubes and stored at −80ºC until assay. After being kept overnight at −20ºC, frozen serum samples were placed in a +4ºC environment. Zn, Cu, manganese (Mn), and selenium (Se) levels were measured from the thawed serum specimens. Biochemical Analyses For measurement of serum Zn and Cu levels, specimens were thinned with 0.2 % HNO3. Specimens were read on an AASflame-type unit using air-acetylene gas. For serum Mn measurement, specimens were thinned with 0.2 % HNO3 and read on an AAS-FIAS (hydride) unit using air-argon gas. For serum Se level measurement, all specimens were thinned with distilled water, and 500 μL diluted serum was mixed with
Cayir et al.
3 mL HClO4-HNO4 acid. The mixture was kept in a boiling water bath for 1 h and then left to cool. Next, 3 mL concentrated HCl was added. Specimens were kept in a boiling water bath for a further 1 h and left to cool. Distilled water was added to the cooled samples and 10 mL specimens obtained. These were then read on an AAS-FIAS (hydride) unit. Statistical Analysis The “Statistical Package for Social Sciences (SPSS) for Windows 20.0” program was used for statistical analysis. All analyzed parameters were presented as mean±SD. Distribution of parameters in the study and control groups was investigated prior to analysis. Student’s t test was used to analyze normally distributed parameters. Pearson’s correlation test was used for correlations. Significance was set at p
