Thyroid hormones and obesity: a known but poorly understood relationship

Area of Science:

• Endocrinology
• Metabolic Diseases
• Thyroid Research

Background:

• Thyroid hormones (TH) regulate crucial biological processes including metabolism, energy expenditure, and thermogenesis.
• Obesity, a chronic inflammatory metabolic disease, involves a positive energy balance and influences thyroid function via adipokines like leptin.
• A bidirectional relationship exists between thyroid dysfunction and obesity, suggesting mutual influence.

Purpose of the Study:

• To elucidate the intricate connection between the thyroid system and obesity.
• To present a hypothetical model emphasizing the role of peripheral thyroid hormone deiodination in positive energy balance.
• To highlight the clinical relevance of assessing thyroid function in obese patients for tailored treatment.

Main Methods:

• Literature review and synthesis of existing research on thyroid hormones and obesity.
• Development of a hypothetical model illustrating the interplay between thyroid function and energy balance.
• Analysis of the impact of obesity on thyroid status and vice versa.

Main Results:

• Thyroid hormones play a significant role in energy expenditure and thermogenesis, influencing body weight.
• Adipose tissue-derived hormones can modulate thyroid function at multiple levels.
• Evidence supports that both thyroid dysfunction can lead to obesity and obesity can cause thyroid alterations.

Conclusions:

• The relationship between the thyroid system and obesity is complex, involving multifaceted interactions.
• Peripheral deiodination of thyroid hormones is proposed as a key factor in establishing positive energy balance in obesity.
• Evaluating thyroid function in obese patients is recommended for optimizing personalized treatment strategies and improving outcomes.