Abstract

Thyroid hormone alteration is common in the general population and recent media have highlighted the controversy surrounding treatment of elite athletes. The aim of this study is to evaluate the thyroid function among athletes in Ekpoma, Edo State. A total of one hundred (100) subjects were recruited for this study which consists of fifty (50) athletes and fifty (50) controls which served as control. Out of the total fifty athletes, 35 were males and 15 were females. The control subjects comprised of 30 males and 20 females. Subject data such as name and gender were obtained. Blood samples (5mls) were collected by vene-puncture into an accurately labelled plain container for both athletes and control. Plasma total T3, T4 and TSH was quantitatively determined using enzyme immuno assay. The results showed that T3 levels were significantly higher (p<0.05) in athletes (2.48±0.71 ng/ml) when compared with the control (1.87±0.28 ng/ml). Also, T4 were significantly higher (p<0.05) in athletes (11.22±2.50 ng/ml) when compared with the control (8.39±1.17 ng/ml). Also, TSH levels were significantly higher (p<0.05) in in athletes (1.20±0.94 ng/ml) when compared with the control (0.59±0.64 ng/ml). The result of this study revealed that T3, T4 and TSH were significantly increased in athletes as compared to non-athletes. This coincides with reports that medium to high intensity, long-duration, aerobic physical activity for several consecutive days produces medium to significant changes in the thyroid function.

Keywords:Thyroid; Hormone; Athlete; T3; T4 and TSH

Abbreviations:T3: Triiodothyronin; T4: Thyroxine; TRE: Thyroid hormone response elements; ANS: 8-anilino-1-napthalene sulfonic acid; TSH: Thyroid stimulating Hormone

Introduction

Athletes are individuals who participate in one or more sports requiring physical prowess, quickness, or stamina. It gets contentious when the term is used in certain sports, such auto racing or golf. Professionals and amateurs are two types of athletes [1]. The majority of professional athletes have incredibly well-developed bodies because to rigorous exercise, prolonged physical training, and precise food plans. Athletes who compete in sports where strength is not as important as endurance typically consume less calories overall [1]. Sound nutrition, excellent training and conditioning, and good genes are all necessary to become an outstanding athlete. A balanced diet is necessary to function at your best. An ambitious athlete can suffer just as much from nutritional ignorance as from proper diet. By following a balanced diet, a person who engages in a general exercise plan (such as 30-40 minutes per day, most days of the week) can meet their nutritional needs.

In order to achieve their nutritional needs, athletes participating in high- or moderate-intensity training programs will need to increase their intake [2]. While it is undeniably true that training is required to increase athletic performance, it has also been clear over time how vital diet is [3]. Three things influence sports success: genetic make-up, level of training, and diet. According to McCardle [4] and Iyevhobu et al. [3], appropriate nutrition is crucial, exercise training is the main way to increase athletic performance, and genetic constitution cannot be changed. According to a 2005 conference hosted by the Sports Authority of India, sports nutrition became crucial since athletes’ physical performance starts to deteriorate long before deficiencies show symptoms. The minimal level of sports nutrition should be attained by the athlete in order for them to function as physically as feasible [5]. Triiodothyronine (T3) and thyroxine (T4) are the two hormones known as thyroid hormones that are generated and secreted by the thyroid gland [6]. The main function of these tyrosine-based hormones is to control metabolism. Part of T3 and T4 is made of iodine. Iodine shortage causes the thyroid tissue to expand, decreases the generation of T3 and T4, and results in simple goitre. Thyroxine (T4), which has a longer half-life than T3, is the primary type of thyroid hormone in the blood [7,8]. According to Horrum [6], the ratio of T4 to T3 released into the blood in humans is roughly 14:1. Within cells, T4 is transformed into active T3 by deiodinases (5′-iodinase).

Iodothyronamine and thyronamine are the byproducts of further processing these through decarboxylation and deiodination. Since dietary selenium is necessary for the synthesis of T3, all three isoforms of deiodinases are selenium-containing enzymes [7]. Thyroid hormone receptors are a well-researched group of nuclear receptors that allow the thyroid hormones to do their job. These receptors attach to DNA sections known as thyroid hormone response elements (TREs) that are close to genes, together with corepressor molecules [9]. In addition to being frequent in the general population, thyroid disease is particularly common in women and may also be common among athletes [4]. In nations with iodine-fortification programs, autoimmune diseases are the most common cause of thyroid abnormalities; however, nutritional variables such as low energy intake and deficiencies in iodine, selenium, iron, and vitamin D can also induce thyroid dysfunction [4]. Furthermore, it’s possible that intense activity causes brief changes in thyroid hormones [10].

Thyroid abnormalities can affect one’s health and ability to function at their best, although their typical clinical signs are quite diverse, nonspecific, and sometimes mistaken for other medical issues. On the other hand, data suggests that decreased thyroid hormone production or an underactive thyroid can impair athletic performance [3]. Triiodothyronine [T3], a thyroid hormone, has been found to have an inverse correlation with VO2max. This means that when elite endurance athletes perform a 20-minute cycle ergometer test at 80% VO2max, their VO2max decreases in proportion to the decrease in thyroid hormone levels [11]. Regretfully, some sportsmen require the medicine because they genuinely have an underactive thyroid. However, as thyroxine is a stimulant thyroid hormone, athletes may be misusing this and utilizing the drug to improve performance [4].

The general public frequently suffers from thyroid disease, and the dispute surrounding the management of hypothyroidism in professional athletes has received attention recently [12]. There is currently no scientific proof that thyroid medication can improve performance [12]. It is not always clear from clinical practice guidelines what constitutes a hypothyroid patient. While free T4 and thyroid-stimulating hormone are advised for thyroid disease screening, some still support the thyrotropin-releasing hormone stimulation test for identifying hypothyroidism in its early stages [12]. It has been shown that hypothyroidism impairs cardiopulmonary function and causes musculoskeletal complaints such as stiffness and weariness [12].

Thus far, no correlation has been shown between hypothyroidism and training state. Thus, it is desirable to investigate if training may cause hypothyroidism in athletes, assess whether thyroid medication can improve performance, and conduct research into a more precisely characterized form of hypothyroidism using provocative testing [13]. Nevertheless, thyroxine therapy, which is not clinically justified, may have negative health consequences, such as an elevated risk of cardiac arrhythmias [4]. Moreover, there is scant or nonexistent data on the evaluation of thyroid hormones and anthropometric metrics in athletes in Ekpoma and Environs. Hence the study is embarked on to provide more information and insight in this area.

Materials and Methods

Study Area

This study was carried out in Ekpoma, Esan-West Local Government Area of Edo State, Nigeria. Ekpoma is geographically defined by latitudes 6.750N and longitude 6.130E with estimated population of 105,310. Ekpoma is one of the administrative seat of the Esan West local government area in Edo State Nigeria. The inhabitants are mainly students, civil servants and farmers [14].

Study Population

A total of one hundred (100) subjects were recruited for this study which consists of fifty (50) athletes and fifty (50) controls which served as control. Out of the total fifty athletes, 35 were males and 15 were females. The control subjects comprised of 30 males and 20 females. Subject data such as name and gender were obtained. The sample size is calculated using the formula described by Araoye [15].
n= n
1+n/N
Where n= sample size
N= population size
n= 100
1 + 10/1000
n = 100 = 90

With population size of about 100 apparently healthy athletes in the centre and over 1000 across the city

Research Design

This study was carried out within five months and it is specifically designed to assess the thyroid hormones (T3, T4 and TSH) and anthropometric parameters in athletes and make comparisons with the control subjects. Blood samples were collected from athletes in Ekpoma, Edo State. The blood samples were centrifuged, and serum was immediately separated from the cells into plain containers with label corresponding to initial blood sample bottle. The serum samples were stored frozen until the time for analysis. The serum obtained was analyzed using standard procedures described by the manufacturer.

Inclusion and Exclusion Criteria

Athletes who gave their informed consent were included in this study. Also, apparently healthy subjects were included as control. While athletes and control subjects having any other type of disease or illness and who did not give their informed consent were excluded in this study.

Sample Collection

Blood samples (5mls) were collected by vene-puncture into an accurately labelled plain container for both athletes and control. The blood samples were centrifuged with a laboratory centrifuge at 4000rpm for 10minutes at room temperature within two hours of collection and the serum separated into a clean plain container which are labelled corresponding to the initial blood samples containers. Analysis was carried out for T3, T4 and TSH.

Sample Analysis

Determination of Total T3 Concentration: Plasma total T3 was quantitatively determined using enzyme immuno assay [16].
a) Principle: In the T3 EIA, a second antibody (goat antimouse IgG) is coated on microtiter wells. measured amount of patient serum, a certain amount of mouse monoclonal anti-T3 antibody, and a constant amount of T3 conjugated with horseradish peroxidase are added to the microtiter wells. During incubation, the mouse anti-T3 antibody is bound to the second antibody on the wells, and T3 and conjugated T3 compete for the limited binding sites on the anti-T3 antibody. After a 60-minute incubation at room temperature, the wells are washed 5 times by water to remove unbound T3 conjugate. A solution of TMB Reagent is then added and incubated for 20 minutes, resulting in the development of blue color. The color development is stopped with the addition of Stop Solution, and the absorbance is measured spectrophotometrically at 450nm. The intensity of the color formed is proportional to the amount of enzyme present and is inversely related to the amount of unlabeled T3 standards assayed in the same way, the concentration of T3 in the unknown sample is then calculated.
b) Procedure: The desired number of coated well in the holder was secured. Data sheet with sample identification was made. 50 μl of standard, samples, and controls was pipetted into appropriate wells. 50 μl of the Antibody Reagent was dispensed into each well. It was mixed thoroughly for 30 seconds. 100μl of Working Conjugate Reagent was added into each well. It was mixed thoroughly for 30 seconds. It was incubated at room temperature for 60 minutes. The incubation mixture was removed by flicking plate contents into a waste container. The microtiter wells were rinsed and flicked 5 times with distilled or deionized water. The wells were stroked sharply onto absorbent paper to remove residual water droplets. 100μl TMB Reagent was dispensed into each well. It was gently mixed for 10 seconds. It was incubated at room temperature in the dark for 20 minutes without shaking. The reaction was stopped by adding 100 μl of Stop Solution to each well. It was gently mixed for 30 seconds. The OD was read at450 nm with a microtiter reader within 15 minutes.

Determination of Total T4 Concentration: Plasma Thyroxin (T4) level was determined using Enzyme immuno assay (EIA) [16].
a) Principle: To measure T4 by competitive immunoassay techniques, a sample of serum or plasma containing the T4 to be quantified is mixed with labeled T4 and T4 antibody. The labeled T4 contains 8-anilino-1-napthalene sulfonic acid (ANS) to inhibit binding of T4 to serum proteins, which would otherwise interfere with the assay. During incubation, a fixed amount of labeled T4 competes with the unlabeled T4 in the sample, standard, or quality control serum for a fixed number of binding sites on the specific T4 antibody. Separation of the unbound T4 from antibody-bound T4 and the subsequent measurement of the labeled fraction of the bound phase completes the test. By comparing results of the unknown sample with those obtained from a series of T4 calibrators, an accurate measurement of the T4 concentration in the sample can be obtained.
b) Procedure: The desired number of coated wells in the holder was secured. 25 μL of standards, specimens, and controls was pipetted into appropriate wells. 100 μL of Working Conjugate Reagent was added into each well. It was mixed thoroughly for 30 seconds. It was incubated at room temperature (18 °C-25 °C) for 60 minutes. The incubation mixture was removed by flicking plate contents into a waste container. The microtiter wells were rinsed and flicked 5 times with distilled H2O. The wells were stoked sharply onto absorbent paper or paper towels to remove all residual water droplets. 100 μL of TMB Reagent was dispensed into each well. It was gently mixed for 5 seconds. It was incubated at room temperature, in the dark, for 20 minutes. The reaction was stopped by adding 100 μL of Stop Solution to each well. It was gently mixed for 30 seconds. It was ensured that all of the blue color changed completely to yellow. The absorbance was read at 450 nm with a microtiter plate reader within 15 minutes.

Determination of Thyroid Stimulating Hormone: Plasma Thyroid stimulating Hormone (TSH) was quantitatively determined using ELISA According to Uotila et al. [17].
a) Principle: The TSH ELISA test is based on the principle of a solid phase enzyme-linked immunosorbent assay. The assay system utilizes a unique monoclonal antibody directed against a distinct antigenic determinant on the intact TSH molecule. Mouse monoclonal anti-TSH antibody is used for solid phase immobilization (on the microtiter wells). A goat anti-TSH antibody is in the antibody-enzyme (horseradish peroxidase) conjugate solution. The test sample is allowed to react simultaneously with the two antibodies, resulting in the TSH molecules being sandwiched between the solid phase and enzyme-linked antibodies. After a 60-minute incubation at room temperature, the wells are washed with water to remove unbound labeled antibodies. A solution of TMB Reagent is added and incubated for 20 minutes, resulting in the development of a blue color. The color development is stopped with the addition of Stop Solution, changing the color to yellow. The concentration of TSH is directly proportional to the color intensity of the test sample. Absorbance is measured spectrophotometrically at 450 nm.
b) Procedure: The desired number of coated wells in the holder was secured. 100 μL of standards, specimens, and controls was dispensed into appropriate wells. 100 μL of Enzyme Conjugate Reagent was dispensed into each well. It was thoroughly mixed for 30 seconds. It was incubated at room temperature (18-25°C) for 60 minutes. The incubation mixture was removed by flicking plate contents into a waste container. The microtiter wells were rinsed and flicked 5 times with distilled or deionized water. The wells were stroked sharply onto absorbent paper or paper towels to remove all residual water droplets. 100 μL of TMB Reagent was dispensed into each well. It was gently mix for 10 seconds. It was incubated at room temperature for 20 minutes. The reaction was stopped by adding 100 μL of Stop Solution to each well. It was gently mixed for 30 seconds allowing the all the blue color to change to yellow color. The absorbance was read at 450 nm with a microtiter well reader within 15 minutes.

Statistical Analysis

Data obtained was analyzed using SPSS (version 21) statistical software package. Results generated were expressed as mean ± SD and P <0.05 was considered statistically significant. The significance of difference among the groups was assessed by Student’s t-test and Analysis of Variance (ANOVA).

Results

The results showed that T3 levels were significantly higher (p<0.05) in athletes (2.48±0.71 ng/ml) when compared with the control (1.87±0.28 ng/ml). Also, T4 were significantly higher (p<0.05) in athletes (11.22±2.50 ng/ml) when compared with the control (8.39±1.17 ng/ml). Also, TSH levels were significantly higher (p<0.05) in in athletes (1.20±0.94 ng/ml) when compared with the control (0.59±0.64 ng/ml). (Table 1).

KEY: n=Sample size, p>0.05= Not significant, p<0.05= Significant.

Table 2 Showed the Comparison of T3, T4 and TSH Levels in Athletes Between Male Subjects and Control. The Results Showed That T3 Levels Were Significantly Higher (P<0.05) In Male Subjects (2.47±0.73 Ng/Ml) When Compared with The Control (1.92±0.26 Ng/Ml). Also, T4 Were Significantly Higher (P<0.05) In Male Subjects (10.69±2.56 Ng/Ml) when compared with the Control (8.68±0.86 Ng/Ml). Also, TSH Levels Were Significantly Higher (P<0.05) In Male Subjects (1.37±1.06 Ng/Ml) when compared with the Control (0.64±0.82 Ng/Ml).

Table 3 showed the comparison of T3, T4 and TSH levels in athletes between female subjects and control. The results showed that T3 levels were significantly higher (p<0.05) in female subjects (2.50±0.70 ng/ml) when compared with the control (1.79±0.29 ng/ml). T4 were significantly higher (p<0.05) in female subjects (12.45±1.91 ng/ml) when compared with the control (7.96±1.44 ng/ml). Also, TSH levels were significantly higher (p<0.05) in female subjects (0.79±0.36 ng/ml) when compared with the control (0.51±0.14 ng/ml).

Table 4 showed the comparison of T3, T4 and TSH levels in athletes between male subjects and female subjects. The results showed that T3 levels were significantly higher (p<0.05) in male subjects (2.47±0.73 ng/ml) when compared with the female subjects (2.50±0.70 ng/ml). T4 were significantly lower (p<0.05) in male subjects (10.69±2.56 ng/ml) when compared with the female subjects (12.45±1.91 ng/ml). Also, TSH levels were significantly higher (p<0.05) in male subjects (1.37±1.06 ng/ml) when compared with the female subjects (0.79±0.36 ng/ml).

Table 5 showed the comparison of T3, T4 and TSH levels of athletes according to age. The result showed a non -significant increase in T3 levels of athletes within the age range of 31-40 years (2.70±0.71 ng/ml) when compared with the age range of 18-30 years (2.50±0.60 ng/ml) and 41 years and above (2.12±0.76 ng/ ml). T4 levels were higher within the age range of 41 years and above (11.55±2.81 ng/ml) when compared with the age range of 31-40 years (11.16±2.51 ng/ml) and 18-30 years (11.04±2.38 ng/ ml). TSH levels were higher within the age range of 18-30 years (1.25±1.07 ng/ml) when compared with the age range of 31-40 years (1.17±0.67 ng/ml) and 41 years and above (1.16±1.53 ng/ ml).

KEY: n=Sample size, p>0.05= Not significant, p<0.05= Significant.

KEY: n=Sample size, p>0.05= Not significant, p<0.05= Significant.

KEY: n=Sample size, p>0.05= Not significant, p<0.05= Significant.

KEY: n=Sample size, p>0.05= Not significant, p<0.05= Significant.
Values in a row with the same superscript are not significantly different at p<0.05.

Discussion

Exercise causes the body to alter hormone levels and biochemical markers, which are components of the hemostatic process that regulate the physiological stresses exercise causes. In order to shed light on the modifications and interactions that follow the physiological changes brought on by exercise, this study looked at thyroid hormones (T3, T4, and TSH), which are linked to the organism’s adaptability as a result of prolonged exercise. Exercises show when the body is under oxidative stress. Although hemostasis returns during recovery, major issues arise, particularly with hormones released during exercise, cells, organs, and hemostasis. Hemostasis seems to be specially provided by regulatory systems [18].

When compared to the control group, the levels of T3, T4, and TSH in athletes were significantly greater. This is consistent with Erdoğan’s [19] findings that both acute and chronic exercise result in the release of thyroid hormones. Thyroid hormones have been shown to enhance physical endurance through their effects on protein, carbs, fat, metabolism, and the body’s ability to adjust to the physiological and metabolic changes that come with exercise [20,21]. The exercise sessions were associated with a significant rise in TSH levels as well as a statistically significant difference in T3 and T4 levels [8]. Akbulut et al. [22] found that vitamin E supplementation and an eight-week workout program altered thyroid hormone metabolism. Chronic exercise has been shown to raise TSH levels and lower T3 and T4 levels [8,23].

According to a study by Chicharro et al. [24], a three-week racing period procedure raised the T4 level while leaving the TSH and T3 levels unchanged. According to a study by Johannsen et al. [25], acute exercise practices significantly altered thyroid hormone levels. In their 2009 study, Sultan & Rashed [26] claimed that a month’s worth of activity and food can alter thyroid hormone levels. In their research, Teixeira et al. [27] discovered that the ten-week exercise program did not significantly alter thyroid hormone levels. Furthermore, TSH and T3 levels changed after acute exercise, but T4 levels remained unchanged, according to research by Masaki et al. [28], Cinar et al. [29] found that participants’ thyroid hormone metabolism was positively impacted by a six-week fitness program and zinc supplement. In a different investigation, Mwafy et al. [30] found that the six-month exercise regimen significantly raised TSH levels while lowering T3 and T4 levels. Thyroid hormone metabolism changes could have been the outcome of physiological reactions to reduce oxidative stress brought on by the exercises performed and to adjust the organism to its current situation.

Conclusion

In conclusion, the study’s findings showed that, in comparison to non-athletes, athletes had significantly higher levels of T3, T4, and TSH. This is consistent with studies that thyroid function changes from medium to considerable when people engage in aerobic physical exercise for multiple days in a row at a high to medium intensity. Therefore, further research is required to better understand the elements that motivate and hinder physical activity, including physical, psychological, social, and environmental factors, in order to design effective intervention programs and baseline values for athletes. Consequently, individual physical activity coaching of patients and a multidisciplinary collaboration between sports physicians, general practitioners, and endocrinologists for an integral health approach of this specific group of people is necessary due to the increased values of thyroid hormones in this study.

Conflict of Interest

The authors declare no conflicts of interest. The authors alone are responsible for the content and the writing of the paper.

Ethical Permission

Ethical approval was obtained from the University Ethics Committee and also informed consent was sought from the subjects before collection of blood samples.

Funding

This research did not receive any grant from funding agencies in the public, commercial, or not-for-profit sectors.

Acknowledgements

The authors would like to acknowledge the management of Ambrose Alli University (AAU), Ekpoma, Edo State, Nigeria for creating the enabling environment for this study. Thanks to all the Laboratory and technical staff of St Kenny Research Consult, Ekpoma, Edo State, Nigeria for their excellent assistance and for providing medical writing support/editorial support in accordance with Good Publication Practice (GPP3) guidelines.

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