During the past few years the concept is emerging that differences in thyroid function status even within the reference range may impact on a wide number of health issues [1,2]. Low-normal thyroid function, as reflected by higher thyroid stimulating hormone (TSH) and/or lower free thyroxine (FT4) or free triiodothyronine (FT3) levels within the euthyroid reference range, associate with enhanced atherosclerosis susceptibility [2]. A high-normal TSH level within the reference range was associated with mortality from cardiovascular diseases (CVD) in a single cohort study, but such a relationship was not found in a recent meta-analysis [3].
