Does subclinical thyroid dysfunction affect blood pressure?

Abstract

A highly sensitive immunoassay for thyroid-stimulating hormone (TSH) was developed in the 1980's for the diagnosis of patients with subclinical thyroid dysfunctions. The frequency of subclinical hypothyroidism is 4.3-11.8% and that of subclinical hyperthyroidism is 0.7-1.5%. 1 An association between subclinical hypothyroidism and cardiovascular risks and the development of atherosclerosis has been reported. 2 Subclinical hyperthyroidism reportedly increases heart rate, the frequency of arrhythmia (including atrial fibrillation), left ventricular mass and the risk of cardiovascular mortality; it also impairs ventricular relaxation. 3 However, the relationship between subclinical thyroid dysfunction and hypertension has remained controversial.In this issue, Cai et al. 4 report the result of a meta-analysis, in which they aimed to determine whether subclinical thyroid dysfunction affects blood pressure. Their findings indicate that subclinical hypothyroidism is associated with a significant risk of increased blood pressure, both systolic and diastolic blood pressure, whereas subclinical hyperthyroidism is not associated with increased blood pressure. 4 They suggest that the controversy regarding the relationship between subclinical hypothyroidism and hypertension may derive from the small number of subjects in the case-control studies, selection bias, or differences in race, lifestyle and genetic background among the sampled population. 4 We need to consider several aspects of thyroidology and laboratory medicine as factors that affected the analysis of the results. These aspects can be divided into the following four concepts.

Exploración de la tensión arterial, morbilidades y adherencia en población adulta de Anserma, Caldas, Colombia : estudio SA-TA.

“…En las demás comorbilidades se encontraron prevalencias significativas de diabetes mellitus , EPOC e hipotiroidismo y patologías que se han encontrado asociadas de forma directa al aumento de las cifras tensionales en la población mundial, tal como lo contrastan los estudios publicados por Yunfei (18) y otros autores (19,20). Respecto a los pacientes que coexisten con cuadros de diabetes mellitus, Alayón y Mosquera (21) enfatizan en el control metabólico y glucémico como factores adyuvantes de importancia, datos que se ajustan a los resultados obtenidos; por su parte, Karoli y Dolinshaia ( 22) postulan la rigidez arterial derivada de la enfermedad pulmonar obstructiva crónica como mecanismo implicado en los pacientes con hipertensión arterial.…”