ObjectiveTo observe the changes of plasma homocysteine (Hcy) and brachial ankle pulse wave velocity (baPWV) in patients with subclinical hypothyroidism, and discuss the relationship between subclinical hypothyroidism and arterial stiffness. MethodSeventy-three patients with subclinical hypothyroidism who were not treated before were divided into two groups according to thyroid stimulating hormone (TSH) level between January 2013 and June 2014. There were 35 patients in group A (4 mU/L < TSH < 10 mU/L) and 38 in group B (TSH ≥ 10 mU/L). Another 30 healthy individuals were selected as controls. Hcy and baPWV were determined in all subjects. ResultsCompared with the controls, patients had significantly higher level of TSH, Hcy and baPWV in group A, and had significantly higher TSH, triacylglycerol (TG), low density lipoprotein cholesterol (LDL)-C, Hcy, and baPWV in group B (P<0.05). Compared with group A, TSH, TG, LDL-C, Hcy, and baPWV in group B patiens were significantly higher (P<0.05). Pearson correlation analysis showed that Hcy was positively correlated with TSH (r=0.353, P<0.01) and baPWV was positively correlated with TSH (r=0.416, P<0.01). ConclusionsHcy level and peripheric arterial stiffness increase in patients with subclinical hypothyroidism. Both of them are correlated positively with TSH.
ObjectiveTo investigate the relationship between thyroid stimulating hormone (TSH) and the blood lipid level in patients with subclinical hypothyroidism (SCH). MethodsWe carried out a retrospective analysis on the clinical data of 264 patients with their first diagnosis of subclinical hypothyroidism without treatment from 2010 January to 2014 January. A total of 288 healthy controls were chosen from communities. The patients were groups based on TSH≥10.0 mU/L and 3.6 mU/L≤ TSH< 10.0 mU/L. We investigated the relationship between TSH and the level of blood lipids by analyzing liver and renal function, blood lipids, thyroid function, and thyroid peroxidase antibody (TPO-Ab) in the patients. ResultsTriglyceride (TG) and high density lipoprotein cholesterol levels were not significantly different among the three groups (P>0.05). Total cholesterol (TC) and low density lipoprotein cholesterol (LDL-C) levels of the group with TSH≥10 mU/L were respectively (5.93±1.12) and (3.82±1.11) mmol/L, which were significantly higher than those in the controls[(4.43±1.12) and (2.66±0.43) mmol/L] (P<0.05). TC, TG and LDL-C levels of the group with 3.6 mU/L≤ TSH< 10.0 mU/L were higher than the controls, but the differences were not significant (P>0.05). After thyroid hormone replacement therapy within 12 weeks, TG, LDL-C, and TC levels of TPO-Ab positive patients with subclinical hypothyroidism (n=112) were respectively (4.62±1.03), (2.97±0.52), and (1.17±0.62) mmol/L, which were significantly lower than those levels before treatment[(5.43±1.18), (3.62±0.58), and (2.03±0.71) mmol/L] (P<0.05). ConclusionThe disorder of lipid metabolism exists in patients with subclinical hypothyroidism. Especially, the level of TSH greater than or equal to 10 mU/L is a high risk factor for dyslipidemia. In TPO-Ab positive patients, therapy of thyroid hormone replacement can effectively improve the blood lipid abnormalities in patients with subclinical hypothyroidism, and it may be an effective measure to improve the disorder of lipid metabolism economically and effectively.
ObjectiveTo systematically review the relationship between subclinical thyroid dysfunction and the risk of atrial fibrillation.MethodsDatabases including PubMed, EMbase, The Cochrane Library, Web of Science, CNKI, CBM, VIP and WanFang Data were electronically searched to collect cohort studies on associations between subclinical thyroid dysfunction and atrial fibrillation from inception to June 2020. Two reviewers independently screened literature, extracted data, and evaluated risk of bias of included studies. Meta-analysis was then performed using RevMan 5.3 software.ResultsA total of 11 studies involving 620 874 subjects and 19 781 cases were included. Meta-analysis showed that subclinical hypothyroidism was not associated with atrial fibrillation (adjusted RR=1.20, 95%CI 0.92 to 1.57, P=0.18) and subclinical hyperthyroidism could increase the risk of atrial fibrillation (adjusted RR=1.65, 95%CI 1.12 to 2.43, P=0.01). Subgroup analysis showed that for the community population, subclinical hypothyroidism was not associated with atrial fibrillation (adjusted RR=1.03, 95%CI 0.84 to 1.26, P=0.81); for cardiac surgery, subclinical hypothyroidism could increase the risk of atrial fibrillation (adjusted RR=2.80, 95%CI 1.51 to 5.19, P=0.001); subclinical hyperthyroidism could increase the risk of atrial fibrillation among patients with TSH≤0.1 mlU/L (adjusted RR=2.06, 95%CI 1.07 to 3.99, P=0.03) and TSH=0.1～0.44 mlU/L (adjusted RR=1.29, 95%CI 1.01 to 1.64, P=0.04). ConclusionsSubclinical hypothyroidism is not associated with atrial fibrillation and subclinical hyperthyroidism can increase the risk of atrial fibrillation. Due to limited quantity and quality of included studies, more high quality studies are needed to verify above conclusions.