ABSTRACT
Background: Thyroid hormone plays an important role in carbohydrate, protein, and lipid and electrolyte metabolism. Studies have demonstrated the association of hypothyroidism with dyslipidaemia. However the impact of high normal TSH on lipid profile is lacking. Also, thyroid hormone is known to influence glomerular filtration rate, and renal electrolyte handling. So, this study compared TSH levels in normal ranges with fasting lipid profile and electrolytes. Objectives: To measure and compare the levels of serum TSH, fasting lipid profile and electrolytes in euthyroid individuals with normal TSH and to correlate serum TSH with lipid profile and electrolytes across different age groups in both sexes. Materials and methods: After obtaining ethical clearance, 2 ml of fasting venous blood sample was drawn from 200 subjects (males=100, females=100) aged between 20-75years who consented to participate. Serum was used for estimation of TSH, lipid profile and electrolytes. TSH was measured by 4th generation Immunoassay in Cobas 6000 e601 autoanalyzer (Roche). The lipid profile and electrolytes were assayed in Cobas 6000 c501 autoanalyzer (Roche). Results: Serum TSH values showed significant positive correlation with total cholesterol (p=<0.001), triglycerides (p=<0.001) and LDL cholesterol (p=<0.001), but did not show any significant correlation with HDL cholesterol. Also serum TSH showed significant negative correlation with sodium (r=- 0.185, p=0.048) and potassium (r=-0.205, p=0.028) levels. Conclusion: TSH and thyroid status can influence lipid and electrolyte metabolism. High normal TSH level may predispose to hypercholesterolemia and hypertriglyceridemia. High normal TSH patients can have lower serum electrolytes.
ABSTRACT
Objetivo: En el hipotiroidismo tanto clínico como subclínico se han descripto alteraciones en el metabolismo lipídico, entre ellas la disminución de colesterol de lipoproteínas de alta densidad (HDL-C). Considerando el rango normal de TSH entre 0.4-3.0 μUI/ml y valores normales altos entre 2.0 y 3.0 μUI/ml, nosotros investigamos la hipótesis de que niveles normales altos de TSH e insulinorresistencia (IR) se encuentran relacionados con HDL-C bajo en mujeres, en ausencia de otros factores concurrentes. Materiales y métodos: Estudiamos en un estudio transversal a 200 mujeres sanas, edad 18-50 años, eutiroideas, normotensas, con anticuerpos antiperoxidasa (ATPO) negativos, no diabéticas, premenopáusicas, IMC 18.0-25.0 Kg/m2, perímetro de cintura ≤ 88 cm; perímetro de cuello ≤ a 35 cm. Se las dividió en 4 grupos, cada uno compuesto por 50 mujeres: Grupo 1 (G1) TSH ≥ 2μU/ml, IR; grupo 2 (G2) TSH ≥ 2μU/ml, no IR; grupo 3 (G3): TSH 0,40 a 1,99 μU/ml, IR; Grupo 4 (G4) TSH 0,40 a 1,99 μU/ml, no IR. Se les midió lípidos, TSH, T4 total y libre (T4L), glucosa e insulina basal y posprandial, índices HOMA y QUICKI y volumen tiroideo (VT). Resultados: Observamos que en el G1 el nivel de HDL-C (46,7± 8,1 mg/dl) fue significativamente menor que en los restantes grupos. (vs G2: 56,8 ± 8,6 mg/dl; vs G3: 51,2 ± 7,6 mg/dl y vs G4: 56,5 ± 9,1 mg/dl. (p<0,01). La frecuencia de pacientes con HDL-C bajo en G1 fue significativamente mayor que en los restantes grupos (vs G2: OR 1,83, IC: 1,23-2,70; vs G3: OR 1,49, IC: 1,04-2,31; vs G4: OR 1,90, IC: 1,29-2,81) . No encontramos diferencias significativas en los niveles de HDL-C entre los restantes grupos. Conclusiones: Observamos en mujeres eutiroideas con TSH normal alta insulinorresistentes, sin otros factores concurrentes, niveles de HDL-C significativamente más bajos que en mujeres no insulinorresistentes y que en mujeres insulinorresistentes con TSH normal baja.
It has been described abnormalities in lipid metabolism in clinical and subclinical hypothyroidism, including the reduction of high-density lipoprotein cholesterol (HDL-C). Considering the normal range for TSH between 0.4-3.0 uUI / ml and high-normal values between 2.0 and 3.0 uUI / ml, we investigated the hypothesis that in euthyroid women, high-normal TSH levels and insulin resistance (IR) are associated with low HDL-C. We observed in euthyroid women with high-normal TSH and insulin resistance, without other factors, a significantly lower level of HDL-C than in non-insulin or insulin resistance women with low-normal TSH.