Women with subclinical hypothyroidism who are younger than 65 years of age may be at increased risk for hypertension compared with women who are older than 65 years of age, according to research published in the Journal of Clinical Medicine.
Despite a relatively benign clinical course compared with overt hypothyroidism, subclinical hypothyroidism, an early form of thyroid dysfunction, has been associated with an increased risk of cardiovascular disease. This is attributed to the link between the cardiovascular system and thyroid hormone. However, the connection between subclinical hypothyroidism and hypertension — a key comorbidity in cardiovascular disease risk — has been less apparent.
To explore the potential association between the disorders, US researchers examined the rates of incident hypertension in women with subclinical hypothyroidism. The research was based on a meta-analysis of 9 case-control, cohort, and cross-sectional studies that reported hypertension incidences in women both with and without subclinical hypothyroidism.
The pooled population included 21,972 women. The researchers divided the population into a middle-aged cohort of women <65 years of age (mean age, 49.6 years) and an older cohort of women ≥65 years of age (mean age, 71.0 years). Subclinical hypothyroidism was associated with an increased incidence of hypertension in the middle-aged subgroup (OR, 1.64; 95% CI, 1.18-2.27), but there was no similar association in the older subgroup (OR, 0.97; 95% CI, 0.80-1.16).
There were a number of limitations in the study. Among them was the inclusion of only female patients with subclinical hypothyroidism, which may reduce the generalizability of the findings across men with the condition. All of the studies in the meta-analysis were observational in nature, suggesting confounding factors could have affected the analysis.
“However,” the researchers said, “based on our result that showed the positive association between [subclinical hypothyroidism] and [hypertension] in middle-aged women, treating [subclinical hypothyroidism] in this patient population when signs of rising blood pressures are observed, regardless of patients’ [thyroid-stimulating hormone] levels, should be considered.”
Kim J, Prasitlumkum N, Randhawa S, Banerjee D. Association between subclinical hypothyroidism and incident hypertension in women: a systematic review and meta-analysis. J Clin Med. 2021;10(15):3318. doi:10.3390/jcm10153318