In addition, our study showed that

In addition, our study showed that TSH was positively correlated with TG, which was also observed in healthy men in Spain [22]. Moreover, a previous study [23] revealed that euthyroid subjects with a TSH level in the high-normal range (2.5-4.5 mIU/L) had higher TG levels than those with TSH levels in the low-normal range (0.3- 2.5 mIU/L) (1.583 ± 0.082 vs. 1.422 ± 0.024 mmol/L, P = 0.023). We speculated that this association could not be explained by the levels of FBG alone, because the FBG in those with high normal TSH were significantly lower than that in those with TSH in the lower limits of the normal range. The positive association between FT3 and log-transformed values of HDL-C in our study was in accordance with the observations of Ness et al. [24], who found that triiodothyronine could raise HDL-C in rat.

Furthermore, we found that the TSH level was significantly higher in the hypercholesterolemic and hypertriglyceridemic subjects than in patients with normal levels of TC and TG. Similar results have been obtained by Lai et al. [25], who demonstrated that the TSH level in the hypertriglyceridemia group was much higher than in the normal control group. In case of lipid profiles, the concentrations of TC, TG and non-HDL-C were significantly higher in patients whose TSH level were in the upper limits than those whose TSH levels were in the lower limits of the normal range. This phenomenon was supported by the HUNT study [7], which suggested that within the clinically normal TSH range, the increasing level of TSH was associated with less favorable lipid concentrations.