CHICAGO – Thyroid-stimulating hormone levels in the upper range of normal are associated with an increased prevalence of cardiovascular risk factors in adolescents, according to a large cross-sectional study.
This finding from the 2007-2008 National Health and Nutrition Examination Survey suggests that thyroid hormone’s influence upon lipid metabolism and glucose homeostasis in teens extends into the euthyroid range and is independent of obesity, Dr. Edmond P. Wickham III said at the annual scientific sessions of the American Heart Association.
He reported on the relationship between TSH level and cardiovascular risk factors in 883 euthyroid adolescent survey participants with a TSH in the normal range of 0.35-5.6 microIU/mL and no history of thyroid disease, diabetes, or antihypertensive therapy. The mean TSH in the 198 obese study participants was 1.89 microIU/mL, significantly higher than the 1.59 microIU/mL in the 154 overweight subjects and the 1.58 microIU/mL in normal-weight individuals.
In univariate analyses, TSH showed a strong linear relationship with body mass index, systolic blood pressure, fasting blood glucose, and total cholesterol, according to Dr. Wickham of Virginia Commonwealth University, Richmond.
In a multivariate analysis controlling for gender and race, the relationship between TSH and BMI remained significant. And the association between TSH and total cholesterol and fasting blood glucose remained significant after BMI as well as race and gender were controlled for. However, after the other factors were controlled for, TSH was no longer associated with systolic blood pressure.
Dr. Wickham and his coworkers carried out this study because little is known about the relationship between subtle thyroid dysfunction and cardiovascular risk factors in teenagers. The issue takes on urgency because of the ongoing epidemic of obesity and weight-related metabolic disturbances in children and adolescents.
Dr. Wickham declared having no relevant financial interests.