Anthropometric profile of sedentary women with and without hypothyroidism

Abstract

Objective

To compare the anthropometric characteristics of sedentary women beginners in a physical exercise program in the gym, which had clinical diagnosis of hypothyroidism, with women who did not have hypothyroidism.

Methods

The sample consisted of eighty women aged between 23 and 45 years who started in a gym at an interval of two years and who had hypothyroidism and the control group, without this pathology, selected in a simple random way. Anthropometric measurements, such as body mass, height, body mass index, abdominal circumference and waist, and body fat percentage were performed. Student's t-test was applied for independent samples between groups and Pearson correlation within groups. The statistical significance adopted was p < 0.05.

Results

The group with hypothyroidism showed significant difference (p = 0.05) compared to control group for the body fat percentage just for women above 35 years, just like women with hypothyroidism above 35 years showed strong association of anthropometric variables with waist hip ratio (r ≥ 0.70).

Conclusion

Sedentary women, above 35 years and affected by hypothyroidism, showed greater association of anthropometric variables with the predisposition to the risk of developing cardiovascular disease compared to their peers without the condition, and below this age range.

Resumen

Objetivo

Comparar las características antropométricas de mujeres sedentarias principiantes en un programa de ejercicio físico en un gimnasio, que presentaban un cuadro clínico diagnosticado de hipotiroidismo, con mujeres que no tenían dicha afección.

Métodos

La muestra fue constituida por 80 mujeres con edades entre los 23 y los 45 años que empezaron en un gimnasio en un intervalo de dos años y que presentaban hipotiroidismo, y el grupo control, sin esta dolencia, seleccionadas de manera aleatoria simple. Se tomaron medidas antropométricas, tales como la masa corporal, la estatura, el índice de masa corporal, la circunferencia de abdomen y de cintura y el porcentaje de grasa corporal. Se aplicó el test t de Student para muestras independientes entre los grupos, así como la correlación de Pearson dentro de los grupos. Se adoptó una significación de p < 0.05.

Resultados

El grupo con hipotiroidismo presentó una diferencia significativa (p ≤ 0.05) en relación con el grupo control para la variable de porcentaje de grasa corporal en mujeres mayores de 35 años, y las mujeres con hipotiroidismo mayores de 35 años mostraron una fuerte asociación de las variables antropométricas con el índice cintura/cadera (r ≥ 0.70).

Conclusión

Las mujeres sedentarias mayores de 35 años y afectadas por hipotiroidismo mostraban mayor asociación de las variables antropométricas, con predisposición a mayor riesgo de desarrollar enfermedades cardiovasculares, en relación con sus compañeras sin dicha dolencia, y por debajo de este rango de edad.

Resumo

Objetivo

Comparar as características antropométricas de mulheres sedentárias iniciantes em um programa de exercício físico em academia, que apresentavam quadro clínico diagnosticado de hipotireoidismo, com mulheres que não apresentavam hipotireoidismo.

Metodologia

A amostra foi constituída por oitenta mulheres com idade entre 23 e 45 anos que ingressaram em academia de ginástica em um intervalo de dois anos e que apresentavam hipotireoidismo e o grupo controle, sem a patologia, selecionada de maneira aleatória simples. Foram realizadas medidas antropométricas, tais com massa corporal, estatura, índice de massa corpórea, circunferência de abdômen e de cintura, e percentual de gordura corporal. Aplicou-se teste t de Student para amostras independentes entre os grupos, bem como correlação de Pearson intragrupo, adotando-se uma significância de p < 0.05.

Resultados

O grupo com hipotireodismo apresentou diferença significativa (p≤0.05) em relação ao grupo controle para a variável do percentual de gordura corporal apenas para as mulheres maiores que 35 anos, bem como as mulheres com hipotireoidismo acima de 35 anos apresentaram forte associação das variáveis antropométricas com o índice de cintura e quadris (r≥0.70).

Conclusão

Mulheres sedentárias, acima dos 35 anos e acometidas por hipotireoidismo, apresentam maior associação das variáveis antropométricas com a predisposição ao risco de desenvolver doenças cardiovasculares em relação aos seus pares sem a patologia, e abaixo desta faixa estaria.

Introduction

The thyroid is an endocrine gland that secretes hormones essential for the regulation of cellular metabolic activities, which are able to increase 60–100%. These hormones are triiodothyronine and thyroxine (T4 and T3, respectively), and their release is regulated by thyroid stimulating hormone (TSH), secreted by the anterior pituitary.¹ Two pathophysiological dysfunctions associated with the thyroid are hyperthyroidism and hypothyroidism (HPO). The latter is characterized by a decrease, or total absence of the secretion of thyroid hormones.² Studies show a higher incidence of cases of HPO in middle-aged and elderly individuals,^2,3 with the highest prevalence in older white men and women, when compared to black elderly.⁴ Moreover, a higher prevalence of this hormonal disorder is observed in females, registering four to eight times more cases than in males.^5,6

It is known that decreased serum concentrations of thyroid hormones cause changes in blood lipids, specifically increases in serum triglycerides and cholesterol, and body composition, with increases in body fatness, observed in both humans^7,8 and animal models,⁹ respectively. With the reduction in metabolic rate, caused by this disease, along with a sedentary lifestyle and poor eating habits,¹⁰ a greater association has been observed between these variables and the risk factors predisposing patients to cardiovascular diseases.^4,11 Since physical activity and cardiorespiratory fitness levels are inversely correlated with blood pressure values and the amount and distribution of body fat.¹²

Thus, in view of the consequent changes in body composition due to conditions such as the HPO associated with hypokinesis, this study aimed to compare the anthropometric characteristics of sedentary women with a clinical diagnosis of HPO, with sedentary women without HPO, who have both started an exercise program at the gym.

Method

Subject

This study is retrospective and descriptive in nature. An initial survey was undertaken investigating the numbers of sedentary women (at least three months of inactivity), with hypothyroidism diagnosed within the past three years and receiving medication, who enrolled in a health club (G-HPO = 40). Additionally, forty women without HPO, but who were also sedentary, were then recruited using simple random sampling to compose the control group (G-CON = 40). All testing was started after approval by the local ethics committee (CAAE 32807414.5.0000.5546) with volunteers signing written and informed consent form (ICF), according to Resolution 466/2012 of the National Health Council (CNS). It is worth noting that a Physical Education professional collected all measures at the assessment room of the academy itself, and all measures were taken from the right side of the body.

Experimental design

All participants answered a health history questionnaire on their sporting background and medical history. From the history, variables included time (in months) with no regular physical exercise or oriented physical activity programs (T-SED), as well as personal and family risk factors which included smoking, stress, heart disease, hypertension, diabetes mellitus, obesity and relevant biochemical changes.

Body mass (BM) and height (Ht) were obtained by a calibrated Welmy mark (Model 110CH; 100 g) mechanical scale. After obtaining these two measures, body mass index (BMI) could then be calculated from the formula: BMI = BM/HT² (kg/m²). Body circumference measurements used taken using a Sanny anthropometric tape (scale of 0.1 mm): waist – horizontally, at the midpoint between the last floating rib and the iliac crest (WC); abdomen – horizontally, above the navel (AC); hip – horizontally and parallel to the ground, based on the trochanteric points (HC). From these measurements waist-to-hip ratio (WHR) was estimated adopting the cutoffs suggested by WHO.¹³

Skinfold measurements were performed according to the anatomic locations suggested by Petroski (1995), using a Lange the caliper (1 mm wide) with constant pressure spring (10 g/mm²). From these measures percentage fat mass (%BF) was calculated from the Jackson and Pollock (1978) prediction equation.

Statistical analysis

Data normality was tested from Kolmorog–Smirnov test and homogeneity by the Levene test. Subsequently, a multivariate analysis of covariance (MANCOVA) was applied, inserting the inactive time in months (T-SBS) sample as a covariate in order to verify the differences between groups. To verify the existence of associations between intra-group variables, a partial correlation test was used, which was adjusted by inserting the T-SED and the age of the sample as control variables. All data were plotted and analyzed using the SPSS software for Windows version 20.0, and expressed using elements of descriptive statistics (mean ± SD), adopting a significance level of 5% (p ≤ 0.05).

Results

The main finding of this study was that the G-HPO group aged over 35 years showed a significantly greater %BF (p = 0.05) compared to G-CON group (Table 1). Women with hypothyroidism over 35 years showed strong correlations for WHR (r ≥ 0.70) (Table 2). It is noteworthy that all G-HPO were taking medication prescribed by their physicians (Puran T4 and Euthyrox, with dosages ranging from 50 to 100 mcg).

Table 1.

Stratification of anthropometric data, using mean and standard deviation of the sample (n = 80).

Group	Age			Body Mass	Heigth	Body Mass Index	%BF	AC	WC	HC	WHR
HYPOTIOIDISM	Under 35 years	n = 31	Mean ± SD	61.07 (±10.87)	162.55 (±7.40)	23.02 (±3.44)	31.34 (±5.96)	81.20 (±8.61)	75.89 (±9.41)	100.19 (±7.32)	0.81 (±0.05)
			Min	45.30	151.10	17.60	19.00	64.90	63.80	87.00	0.71
			Max	98.60	185.00	36.70	48.78	113.50	111.00	121.50	0.93
	>35 anos	n = 9	Mean ± SD	63.34 (±10.27)	159.30 (±5.32)	24.92 (±3.27)	32.84^* (±5.87)	85.41 (±9.09)	79.72 (±10.46)	100.96 (±6.15)	0.84 (±0.05)
			Min	51.90	149.30	21.10	23.64	70.70	64.00	93.80	0.73
			Max	87.10	166.50	32.00	43.15	103.70	102.50	114.50	0.91
CONTROL	Under 35 years	n = 30	Mean ± SD	58.05 (±6.73)	163.36 (±5.33)	21.72 (±2.04)	28.69 (±5.66)	77.77 (±5.51)	72.35 (±5.37)	98.37 (±5.91)	0.79 (±0.05)
			Min	47.90	154.20	18.50	17.60	66.00	63.90	88.80	0.70
			Max	77.20	175.00	26.20	42.06	91.20	86.50	113.20	0.88
	>35 years	n = 10	Mean ± SD	58.81 (±5.53)	161.47 (±3.56)	22.55 (±1.93)	30.12 (±4.74)	81.36 (±5.42)	75.37 (±4.55)	99.20 (±4.59)	0.82 (±0.05)
			Min	52.70	152.50	20.60	22.58	71.80	69.50	93.50	0.71
			Max	68.30	165.60	25.50	37.89	90.80	85.30	107.00	0.88

SD: Standard Deviation; Min: Minimum; Max: Maximun; %BF: Percent Body Fat; AC: Abdominal Circumference; WC: Waist Circumference; HC: Hip Circumference; WHR: Waist-to-Hip Ratio.

*

p ≤ 0.05 compared to G-CON.

Table 2.

Intragroup relations for women over 35 years of both investigated groups.

G-Con: Control Group; G-HPO: Hypothyroidism Group; BM: Body Mass, BMI: Body Mass Index; %BF: Percent Body Fat; AC: Abdominal Circumference; WC: Waist Circumference; HC: Hip Circumference; WHR: Waist-to-Hip Ratio.

^*p ≤ 0.05.

As for intra-group associations, strong and very strong correlations for G-HPO group were observed in all anthropometric variables, except WHR (r = 0.43) and moderate to strong correlations were also observed in the G-CON group in women aged under 35 years (Table 3).

Table 3.

Intragroup relations for women under 35 years of both investigated groups.

G-Con: Control Group; G-HPO: Hypothyroidism Group; BM: Body Mass, BMI: Body Mass Index; %BF: Percent Body Fat; AC: Abdominal Circumference; WC: Waist Circumference; HC: Hip Circumference; WHR: Waist-to-Hip Ratio.

^*p ≤ 0.05.

In the intra-group correlations for women over 35 years, moderate and strong correlations were found for all anthropometric variables, with the largest association of these variables being WHR in this age group (Table 2).

Discussion

This study compared the anthropometric characteristics of a group of women diagnosed with HPO, with women who did not have the same pathology. Both groups were composed of sedentary women who had initiated a gym based exercise program.

The main result of this study was that women diagnosed with HPO who were above 35 years of age had a higher percentage of body fat when compared to those who did not have the same pathology. This difference can be explained by an accumulation of body fat due to low concentrations of thyroid hormones, which are responsible for the regulation of cellular metabolic activity, thus compromising metabolism and lipid profile of these individuals.^14,15

When analyzing BMI separately, it was noted that all the groups presented within the “healthy” range, in which the reference values were 18.6–24.9 kg/m².¹⁶ It is possible that the women with HPO presented serum concentrations of thyroid hormones within the normal range, suggesting the effectiveness of their prescribed medication. Lindeman et al.¹⁷ found a possible association between hypothyroidism and BMI in elderly women and a reverse trend for men. The BMI values observed in the present are similar to those observed by Knudsen et al.,¹⁸ which state that the amount of serum TSH is positively associated with BMI.

As for the %BF also analyzed separately, high values were observed in all groups; according to the American College of Sports Medicine (ACSM), recommended values should approximate 25%.¹⁹ According to Figueroa et al.,²⁰ the “state” of the thyroid does not seem to be the dominant causal variable in the overweight condition as confirmed by Bakiner et al.²¹ who stated that individuals treated with hormone therapy for hypothyroidism correction do not demonstrate significant changes in body weight and fat percentage. Bakiner et al.²¹ and Lloyd et al.²² reported that individuals diagnosed with hypothyroidism usually show increased fat percentage, followed by change in body weight, since abnormalities in the secretion of thyroid hormones are related to disorders in lipid metabolism.^15,16

Correlations for WHR were observed, although values are within those reference values recommended by the WHO.¹³ This variable showed a positive association with other anthropometric variables only for the G-HPO group in those aged over 35 years (Table 2), suggesting greater susceptibility to developing cardiovascular diseases, due to increased fat accumulation in the central region of the body at this age. Studies suggest that atherosclerosis and myocardial infarction are more common in people with hypothyroidism due to atherosclerotic lipid profile presented by this population.^23,24 In addition, Korkmaz et al.²⁵ affirm that there is a tendency for people with hypothyroidism to have higher concentrations of epicardial adipose tissue, possibly resulting from this most central concentration of adipose tissue, a factor that would increase cardiovascular risk.

Finally, according to Tables 2 and 3, positive correlations between variables were observed within groups. The correlations obtained from the G-HPO were high than the G-CON in both age groups, signaling a pattern of altered body composition, thereby enhancing the sedentary lifestyle effects, aggravated by the presence of hypothyroidism.^10,12 Therefore, it is emphasized that the display of such correlations reinforces the need for anthropometric measurements to be performed prior to beginning any exercise program and not just for them to be analyzed once training has started. They should also be interpreted diagnostically if necessary, with referral to a relevant health care professional.

The main limitation of this study, relates to not obtaining environmental variables that could interfere the diagnosis of hypothyroidism and influence the body composition of volunteers.

We conclude that sedentary women, over 35 years of age and affected by hypothyroidism, showed increased risk of cardiovascular disease compared to their peers without the condition as indicated by predisposing anthropometric variables.

Ethical disclosures

Protection of human and animal subjects

The authors declare that the procedures followed were in accordance with the regulations of the relevant clinical research ethics committee and with those of the Code of Ethics of the World Medical Association (Declaration of Helsinki).

Confidentiality of data

The authors declare that they have followed the protocols of their work center on the publication of patient data.

Right to privacy and informed consent

The authors have obtained the written informed consent of the patients or subjects mentioned in the article. The corresponding author is in possession of this document.

Conflict of interests

The authors have no conflicts of interest to declare.