A cross-sectional survey of relationship between serum TSH level and blood pressure

Abstract

It is still controversial whether subclinical hypothyroidism and euthyroidism affect blood pressure. The study aimed to explore the relationship between different levels of thyroid-stimulating hormone (TSH) and blood pressure in the participants with subclinical hypothyroidism and euthyroidism. A total of 1319 participants were administered a questionnaire survey, and their blood pressure, height and body weight measurements were taken. Blood samples were taken to test serum TSH. FT3 and FT4 were further examined if TSH was abnormal. Participants were divided into euthyroid group and subclinical hypothyroidism group. Euthyroid group was further divided into three groups: group A (TSH 0.3-0.99 mIU l À1 ), group B (TSH 1.0-1.9 mIU l À1) and group C (TSH 1.91-4.8 mIU l À1 ). Results showed that different levels of serum TSH had no relation with systolic blood pressure (SBP) and diastolic blood pressure (DBP). The prevalence of hypertension in subclinical hypothyroidism group was significantly higher than euthyroid group in females (41.3 vs 25.6%, Po0.05). The risk of hypertension in subclinical hypothyroidism group was significantly higher than that in the euthyroid group after adjusted for age, gender, smoking status, HOMA-IR (homoeostasis model assessment of insulin resistance) and body mass index (odds ratio (OR) ¼ 1.753, 95% confidence interval (CI) 1.067-2.879, P ¼ 0.027). This association was stronger in females (OR ¼ 3.545, 95% CI 1.576-7.975, P ¼ 0.004), but there was no statistical significance in males. Within normal range of TSH, both SBP and DBP were similar among the three groups. The prevalence and risk of hypertension were also similar among the three groups. In conclusion, the prevalence of hypertension in subclinical hypothyroidism group was significantly higher than in euthyroid group in females. Change of TSH in normal range did not affect blood pressure.

Subclinical hypothyroidism represents an additional risk factor for coronary artery calcification, especially in subjects with intermediate and high cardiovascular risk scores

“…This result is in accordance with the hypothesis that SCH leads to atherosclerosis by augmenting classical CV risk factors such as dyslipidaemia and systemic hypertension (6). Indeed, positive correlations between serum TSH and blood pressure (35,36) and between TSH and serum lipids (2, 37, 38) have been demonstrated in several studies. In addition, a potential relationship between SCH and metabolic syndrome and a reduction in insulin sensitivity have also been proposed (39,40), and SCH also seems to be associated with additional CV risk factors.…”

Thyroid function and the metabolic syndrome in older persons: a population-based study

“…In studies comparing euthyroid subjects with subclinical hypothyroid subjects, people in the subclinical hypothyroid group have a higher prevalence of high blood pressure and dyslipidemia (1,2). Also in the euthyroid range, serum TSH is positively associated with blood pressure, total cholesterol (TC), triglycerides, and LDL, and negatively associated with HDL (3,4).…”

Blood pressure levels in patients with subclinical thyroid dysfunction: a meta-analysis of cross-sectional data

“…4 Within the past 5 years, six large cross-sectional studies on this topic have produced conflicting results. [5][6][7][8][9][10] Three studies concluded that subjects with subclinical hypothyroidism had a significantly higher systolic blood pressure (SBP) than euthyroid subjects (age, sex and body mass index adjusted). 5,9,10 However, discrepancies between study results may have arisen from differences in the level of adjustment for other cardiovascular risk factors among the included studies.…”