Background:
Most prior studies evaluating thyroid function and cardiac structure and function have been small and have not included the full spectrum of thyroid function hormones.
Methods:
Among 5122 ARIC participants (aged 66- 90 at the visit 5, 2011-2013) we evaluated the cross-sectional associations of clinical categories of thyroid function and thyroid hormone levels (triidothyronine [T3], thyroxine [T4], and thyroid-stimulating hormone [TSH]) with left ventricular structure, systolic function, and diastolic function based on echocardiogram after accounting for potential confounders including prevalent coronary heart disease and heart failure.
Results:
There were 417 participants (9.4%) with hypothyroidism and 155 participants (3.5%) with hyperthyroidism. Hypothyroidism tended to be associated with more echocardiographic parameters compared to hyperthyroidism. Among individual thyroid hormones, T3 was most robustly associated with left ventricular structure and function. Specifically, lower T3 level was associated with higher left ventricular mass and diameter and reduced systolic and diastolic dysfunction (Figure).
Conclusions:
In community-dwelling older adults, hypothyroidism was more evidently associated with altered left ventricular structure and function than hyperthyroidism. Among T3, T4, and TSH, lower T3 demonstrated most robust associations. Our findings highlight the importance of recognizing hypothyroidism for cardiac health and assessing T3 in addition to T4 and TSH for thyroid function assessment among older adults.