Thyroid Hormones and Coronary Artery Calcification in Euthyroid Men and Women

Abstract

Objective— Overt and subclinical hypothyroidism are risk factors for atherosclerosis. It is unclear whether thyroid hormone levels within the normal range are also associated with atherosclerosis measured by coronary artery calcium (CAC). Approach and Results— We conducted a cross-sectional study of 41 403 apparently healthy young and middle-aged men and women with normal thyroid hormone levels. Free thyroxin, free triiodothyronine, and thyroid-stimulating hormone levels were measured by electrochemiluminescent immunoassay. CAC score was measured by multidetector computed tomography. The multivariable adjusted CAC ratios comparing the highest versus the lowest quartile of thyroid hormones were 0.74 (95% confidence interval, 0.60–0.91; P for trend <0.001) for free thyroxin, 0.81 (0.66–1.00; P for trend=0.05) for free triiodothyronine, and 0.78 (0.64–0.95; P for trend=0.01) for thyroid-stimulating hormone. Similarly, the odds ratios for detectable CAC (CAC >0) comparing the highest versus the lowest quartiles of thyroid hormones were 0.87 (0.79–0.96; P for linear trend <0.001) for free thyroxin, 0.90 (0.82–0.99; P for linear trend=0.02) for free triiodothyronine, and 0.91 (0.83–1.00; P for linear trend=0.03) for thyroid-stimulating hormone. Conclusions— In a large cohort of apparently healthy young and middle-aged euthyroid men and women, low-normal free thyroxin and thyroid-stimulating hormone were associated with a higher prevalence of subclinical coronary artery disease and with a greater degree of coronary calcification.

Increased leptin/adiponectin ratio relates to low-normal thyroid function in metabolic syndrome

“…In line with this concept, low-normal thyroid function is associated with a greater increased intima media thickness (cIMT), an established biomarker of subclinical atherosclerosis [3, 4]. Furthermore, low-normal thyroid function is associated with increased coronary artery calcification [5] and progression thereof [6], although an association of a high-normal TSH level with increased coronary heart disease risk has been variably reported [7, 8]. …”

Association of low baseline free thyroxin levels with progression of coronary artery calcification over 4 years in euthyroid subjects: the Kangbuk Samsung Health Study

“…Although the CAC score is a reliable surrogate marker of atherosclerotic vascular changes when it is measured by MDCT, only a few studies have observed an association between thyroid hormone levels and CAC in euthyroid individuals. 19,20,23 One study found that FT4, but not TSH, was inversely associated with the CACS in men but not in women. Another study with a larger sample size (n = 41 403) found that both FT4 and TSH were inversely associated with the CACS.…”

“…It is not yet clear whether variations in thyroid hormone levels within the normal range are associated with subclinical atherosclerosis as measured by the CACS. However, one large cohort study found that low‐normal free thyroxin and thyroid‐stimulating hormone (TSH) levels were associated with higher prevalences of subclinical coronary artery disease, specifically, atherosclerosis as measured by the CACS . Another study of euthyroid individuals found an inverse association between free thyroxin (FT4) and coronary artery calcification (CAC) in men .…”

Bidirectional Translation in Cardiovascular Calcification

“…Furthermore, in a cohort of over 41 thousand healthy young and middle-aged euthyroid men and women, low levels of normal free thyroxin and thyroid-stimulating hormone were associated with a higher prevalence of coronary calcification 55 .…”