24% of Adults With Hypertension Have Subclinical Hypothyroidism

  •  The SCH prevalence rate was higher among women with hypertension, at 28%, compared with 20% among normotensive women. Among men, the prevalence of SCH was 21% among those with hypertension and 13% among the normotensive men.

Why This Matters

  •  Hypertension rates are increasing; it potentially affects up to 28% of the Chinese population.

  •  People with SCH often lack obvious signs and symptoms, making it easy to miss.

  •  Elevated blood pressure is positively correlated with thyroid-related diseases, but few studies have investigated the prevalence of SCH among persons with hypertension.

  •  Prior study results documented a close relationship between SCH prevalence and hypertension, but the pathogenic relationship between the two is not clear.


Study Design

  •  This was a cross-sectional, observational study of 2818 randomly selected adults from Gansu Province, China.

  •  The authors defined hypertension as a blood pressure of at least 140/90 mm Hg, normotension as a blood pressure of less than 120/80 mm Hg, and high normal blood pressure as pressures between these values.

  •  They defined persons with SCH as those with normal levels of free thyroxine and free triiodothyronine and an abnormally elevated level of thyroid-stimulating hormone (TSH).


Key Results

  •  Among the 2818 people studied, 21% had hypertension, 43% had high normal blood pressure, and 36% were normotensive. The overall prevalence of SCH was 21%.

  •  The prevalence of SCH was significantly higher among those with hypertension, 24%, than among those with normal blood pressure, 17%, regardless of age.

  •  The prevalence of SCH was significantly higher in women than men in the normotensive, high-normal, and hypertensive groups: 20% vs 13%, 28% vs 18%, and 28% vs 21%, respectively.

  •  The prevalence of SCH in hypertensive persons aged 60 years or younger (86% of the total study population) was significantly higher than in the normotensive population: 29% compared with 18%.

  •  In a multivariate analysis, increased heart rate was significantly linked with a lower prevalence of SCH among people with hypertension. Measures that were significantly linked with an increased prevalence of SCH in people with hypertension were increased levels of triglycerides, low-density lipoprotein cholesterol, TSH-receptor antibody, thyroglobulin antibody, and fasting plasma glucose.



  •  There is uncertainty about how well a single measure of a person's TSH level accurately reflects thyroid function.