Interplay between metabolic and thyroid parameters in obese pubertal children. Does visceral adipose tissue make the first move?

ABSTRACT

Objectives: The mechanisms of obesity-associated thyroid dysfunction in children are incompletely deciphered. We aimed to evaluate whether visceral adipose tissue (VAT), insulin resistance (IR), inflammation, oxidative stress (OS) are involved in thyroid morpho-functional changes in pubertal obese children.

Methods: We recruited 43 obese pubertal children without history of thyroid pathology. Metabolic and thyroid parameters (visceral fat thickness [VFT], waist/hip ratio [WHR], waist/height ratio [WHtR], insulin, glucose, liver parameters, thyroid stimulation hormone [TSH], free thyroxine [FT4], free triiodothyronine [FT3], thyroid and abdominal ultrasonography) were evaluated. Serum monocyte chemoattractant protein-1 (MCP-1) and malondialdehyde (MDA) levels were quantified as markers of inflammation and OS.

Results: VFT correlated positively both with WHR (p= 0.034) and the presence of thyroid nodules (p= 0.036). WHR associated with TSH (p= 0.005), FT3/FT4 (p= 0.033) and was independently associated with FT3/FT4 increase (p< 0.001). HOMA-IR increased with visceral obesity (waist circumference, p= 0.001; WHR, p= 0.018; WHtR: p< 0.001), hepatic impairment (alanine aminotransferase, p= 0.019) and hepatic steatosis (HS; p= 0.013) and correlated positively with FT3/FT4 (p= 0.036). TSH was significantly higher in subjects with HS versus those without HS (p= 0.007) and logistic regression analysis identified TSH as a risk factor for HS (p= 0.014). MDA correlated positively with MCP-1 (p= 0.021).

Conclusion: VAT and IR may be responsible for changes in thyroid parameters associated with obesity: elevated TSH, FT3/FT4 levels and increased prevalence of thyroid nodules. WHR was predictive of increased FT3/FT4. In obese children, there is an interdependent relationship between HS and thyroid function.

KEYWORDS:

• Visceral adiposity
• obesity
• insulin resistance
• systemic inflammation
• thyroid disorders

Authors contributed

All authors contributed to the writing of the manuscript, have read and abided by the statement of ethical standards for manuscript submitted to the Acta Clinica Belgica.

Acknowledgments

We would like to express our gratitude to the management unit of the Infectious Diseases Clinical Hospital, Cluj-Napoca, Romania, for its assistance and support. Also, we are sincerely thankful to the journal’s anonymous reviewers for their careful reading of our manuscript and their insightful comments and suggestions.

Disclosure statement

No potential conflict of interest was reported by the authors.