Date of Award

4-9-2018

Document Type

Thesis and Dissertation

Degree Name

Master of Science (MS)

Department

School of Kinesiology and Recreation

First Advisor

Kelly Laurson

Abstract

The global prevalence of metabolic syndrome (MetS) and its associated components (high fasting glucose, waist circumference, blood pressure, triglycerides, and low HDL) have increased over the past few decades. In addition, abnormal thyroid hormone levels have been found to manifest in a cascade of metabolic dysfunction, which may be linked to MetS in youth. PURPOSE: The purpose of the study is to investigate the association between MetS, its components, and markers of thyroid function in a nationally-representative sample of adolescents. METHODS: The National Health and Nutrition Examination Survey III (1988-1994) collected data on the components of metabolic syndrome and thyroid function in 1,322 adolescents aged 12-18.9 years (613 males and 709 females). Participants were grouped based on MetS status, number of MetS components, and markers of thyroid function using age- and sex-specific reference values (including thyroid stimulating hormone [TSH], thyroxine [T4], antimicrosomal antibody [AMA], and anti-thyroglobulin antibody [TgAb]. Logistic models were used to predict the status of the thyroid markers (as high/low) from MetS status, controlling for age, sex, and race/ethnicity. RESULTS: In males MetS prevalence was 6.1% (16.7% had at least 2 MetS components). In females, MetS prevalence was 4.8% (22% had at least 2 MetS components). Males with ≥2 MetS components had significantly higher odds of being TPOAb positive (OR = 7.9, 95%CI [1.7,36.8]) and were not likely to be TgAb positive (OR = 0.7 95%CI [0.1,6.4]). Females with ≥2 MetS components were 1.8 times more likely to be TPOAb positive (OR = 1.8 95%CI [0.5,6.5]) and 1.3 times more likely to be TgAb positive (OR = 1.3 95%CI [0.4-4.3]). In males, TG, WC, HDL-C, and DBP were significantly increased in the elevated TPOAb group (all P<0.05). No significant differences were observed in females. Odds ratios for MetS components were calculated according to TSH decile. Male subjects in the top decile of TSH had significantly higher odds of elevated TG; females were less likely to have increased BP (both P<0.05). Males in the bottom TSH decile were unlikely to present with elevated fasting glucose while females are unlikely to have elevated TG, WC, or fasting glucose (all P<0.05). CONCLUSION: Covert thyroid dysfunction often accompanies many components of MetS. Therefore, we encourage future researchers to investigate the clinical utility of restoring thyroid function as a component in the consolidation of treatment for MetS. The present study is unable to explain the effect of TPOAb on MetS, although we do believe there is a link. Research should be conducted on the biochemical processes in which TPOAb may influence MetS. Plausibly, the present study and studies conducted prior to ours suggest a bidirectional relationship between MetS and thyroid dysfunction

Comments

Imported from ProQuest Austin_ilstu_0092N_11205.pdf

Page Count

39

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