Height and Active Arterial Wall Thickening in Relation to Thyroid Cysts Status among Elderly Japanese: A Prospective Study

SIMPLE SUMMARY: Since active endothelial repair leads to arterial wall thickening, as defined based on the degree of yearly progression in arterial wall thickness, arterial wall thickening could indicate endothelial repair activity. Recent studies indicate that individuals with short stature might have disadvantages in endothelial healing. Therefore, the need for endothelial repair should be much stronger in individuals with short versus tall stature. Thus, height could be inversely associated with arterial wall thickness. Aging is a process associated with declining capacity for endothelial repair. In addition, as thyroid hormone plays an important role in activating endothelial repair, only individuals with enough capacity to produce thyroid hormone can activate endothelial repair efficiently. These findings indicate that height could be inversely associated with active arterial wall thickening among participants without latent thyroid damage. Our previous studies with thyroid ultrasound revealed that the absence of thyroid cysts could indicate the presence of latent damage of the ability to produce thyroid hormone. In this study, a significant inverse association between height and active arterial wall thickening was observed only among participants with thyroid cysts; this finding can help clarify a novel mechanism in vascular remodeling. ABSTRACT: Height is inversely associated with inflammation that stimulates endothelial repair. In our previous study involving elderly men aged 60–69 years, we found that active arterial wall thickening, which is known as the process of endothelial repair, requires CD34-positive cells. As thyroid hormone regulates CD34-positive cell production and as the absence of thyroid cysts might indicate latent damage in the thyroid, the status of thyroid cysts possibly influences the association between height and active arterial wall thickening. We conducted a 2-year follow-up study of Japanese aged 60–69 years. For participants with thyroid cysts, height was significantly inversely associated with active arterial wall thickening (thyroid function and baseline CIMT adjusted odds ratio of active arterial wall thickening for one increment of standard deviation of height (5.7 cm for men and 4.8 cm for women), 0.66 [0.49, 0.89]), while for those without thyroid cysts, a positive tendency between the two parameters was observed (1.19 [0.96, 1.50]). An inverse association between height and active arterial wall thickening was observed only for elderly participants with thyroid cysts possibly because of a supportive role of thyroid hormone, as the absence of thyroid cysts might indicate latent damage in the thyroid.