To the Editor: In their Scientific Review and Clinical Applications article on subclinical thyroid disease,1 Dr Surks and colleagues stated that although several studies suggested that levothyroxine therapy will reduce total and low-density lipoprotein (LDL) cholesterol levels in patients with subclinical hypothyroidism,2 this finding had not been confirmed in randomized placebo-controlled trials, including a study for which 2 of us were authors.3 This is not accurate. In our study, patients with subclinical hypothyroidism had total and LDL cholesterol levels significantly higher than controls, which correlated with baseline serum thyrotropin (TSH) levels. Six months of levothyroxine therapy resulted in a significant decrease of both total and LDL cholesterol concentrations proportional to the baseline levels (–8.0% and –10.2%, respectively). Although greater improvement in total and LDL cholesterol levels was detected in patients with TSH levels of more than 6.0 mIU/L (–11.3% and –15.6%, respectively), reduction in both total and LDL cholesterol concentrations was also observed in patients with lower TSH levels (–6.7%, P< .05 and –8.3%, P = .08, respectively). Overall, these findings suggest that the increase in total and LDL cholesterol levels in patients with subclinical hypothyroidism is related to TSH levels, and that a minimal treatment-induced change in TSH concentration can have a measurable effect on lipoprotein profile.
Intima-media thickness (IMT) is a marker of early atherosclerosis changes and a surrogate end point for cardiovascular events. In a randomized placebo-controlled study,4 we found that an early increase of IMT is present in patients with subclinical hypothyroidism and that levothyroxine treatment is able to improve the atherogenic lipoprotein profile and decrease the mean IMT even in patients with TSH levels of less than 10 mIU/L. These data suggest that subclinical hypothyroidism is a risk factor for cardiovascular disease and that the treatment of this mild thyroid dysfunction may be advisable not only in patients with TSH levels of more than 10 mIU/L but also in those with lower serum TSH levels.
Country-Specific Mortality and Growth Failure in Infancy and Yound Children and Association With Material Stature
Use interactive graphics and maps to view and sort country-specific infant and early dhildhood mortality and growth failure data and their association with maternal
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