Relationship of TSH levels with cardiometabolic risk factors in US youth and reference percentiles for thyroid function.
Thyroid hormones play an important role in the metabolic homeostasis and higher levels have been associated with cardiometabolic risk.To examine the association of cardiometabolic risk factors with TSH levels in US youth.Cross-sectional study of youth aged 12-18 years without known thyroid abnormalities from five National Health and Nutrition Examination Survey cycles (n=2,818) representing 15.4 million US children. Subclinical hypothyroidism (SH) was defined as TSH levels 4.5-10 mIU/L. Assessed cardiometabolic risk factors include abdominal obesity (waist circumference > 90 th percentile), hypertriglyceridemia (TG ≥130 mg/dL), low HDL cholesterol (HDL-C < 40 mg/dL), elevated blood pressure (SBP and DBP ≥90 th percentile), hyperglycemia (FBG ≥100 mg/dL, or known diabetes), insulin resistance (HOMA-IR > 3.16) and elevated alanine transferase (ALT ≥ 50 U/L for boys and ≥ 44 U/L for girls). Age and sex- specific percentiles for thyroid parameters were calculated.In this cohort of youth (51.3% male), 31.2% had overweight/obesity. The prevalence of SH was 2.0 % (95% CI 1.2-3.1). The median TSH levels were higher in youth with overweight/obesity (p 75 th percentile requires further study.