Minor Alterations in Thyroid – Function Tests Associated With Diabetes Mellitus and Obesity in Outpatients Without Known Thyroid Illness

Abstract

Thyroid function tests might be affected by diabetes and obesity. To evaluate the influence of these parameters in routine conditions, 72 diabetic and 53 non-diabetic outpatients without known thyroid diseases or severe chronic illness were recruited over a 7-month period. For each patient, dosages of thyrotropin (TSH), total and free thyroxine (TT4 and FT4, respectively), total and free triiodothyronine (TT3 and FT3) and T3 resin uptake (T3RU) were performed by radioimmunoassays. The simultaneous influence of various parameters known to affect thyroid-function tests was evaluated by multivariate linear regression. The studied variables included gender, age, glucosteroids, estrogens, tobacco habits, iodine contacts, body mass index (BMI) and diabetes mellitus. Tobacco habits and iodine contacts did not influence any tests. As expected, estrogens induced an increase in TT4 and TT3 values (p < 0.001 and 0.020, respectively) associated with a decrease in T3RU (p < 0.001). Consequently, females had lower T3RU than males (p < 0.0001). Corticotherapy was associated with decreased TSH values (p = 0.022). TT3 and FT3 decreased with age (p < 0.001), whereas T3RU and FT4 increased (p = 0.020 and 0.004, respectively). In contrast to an increase in TSH (p = 0.006), TT4 and FT4 decreased at higher BMI levels (p = 0.018 and 0.004, respectively), which is consistent with subclinical hypothyroidism. In diabetic patients, TSH was lower than in nondiabetic subjects (p = 0.039). Thus, the present study indicates that besides known parameters such as age and drugs, thyroid-function tests can also be altered by diabetes mellitus and obesity.

Problemas clínicos pré-anestésicos de pacientes morbidamente obesos submetidos a cirurgias bariátricas: comparação com pacientes não obesos

“…Ambas as condições são fatores de risco de aterosclerose e cardiopatia isquêmica e são controladas pela cirurgia bariátrica 12 . Hipotireoidismo sub-clínico ocorre mais freqüentemente em pacientes obesos e/ou diabéticos e pode ser responsável pela baixa taxa de gasto de energia em repouso encontrada em alguns pacientes obesos 13,14 . A esteatose hepática não alcoólica ocorre freqüentemente em pacientes obesos e pode progredir para cirrose hepática e insuficiência hepática.…”

“…Both conditions are risk factors for arteriosclerosis and ischemic heart disease, and are controlled by gastric bypass 12 . Sub-clinical hypothyroidism is more frequent in obese and/or diabetes patients and may be responsible for the low resting energy expenditure rate found in some obese patients 13,14 Non-alcoholic fatty liver is frequent in obese patients and may evolve to liver cirrhosis and failure. Treating obesity will improve this condition.…”

Association between Thyroid Function and Body Mass Index: A 10-Year Follow-Up

“…Despite the conflicting data available, several cross-sectional studies have shown a significant positive association between body mass index (BMI) and serum thyrotropin (TSH), even for reference range values [5,6,7]. Also there are controversial data regarding association between BMI and serum free thyroid hormones, most documenting negative association [8,9,10]. However, longitudinal surveys in this field are scarce [11,12,13,14,15,16,17].…”

“Study of Total Cholesterol (Tc), Triacylglycerols (Tg), High Density Lipoprotein Cholesterol (Hdl-C) in Type Ii Diabetes Mellitus.”

“…Diabetes mellitus (DM) is the most common metabolic disorder affecting the people all over the world. It is a group of metabolic disorders characterized by hyperglycemia resulting from defect in insulin secretion, insulin action, or both [1]. It is a clinical syndrome characterized by hyperglycemia, caused by a complicated interplay of genes, obesity, environment, increased glucose production in liver, increased fat breakdown, and an absolute or relative deficiency of insulin.…”