Association between thyroid function and obesity phenotypes in healthy euthyroid individuals: an investigation based on Tehran Thyroid Study

Abstract

Abstract Aims We investigated whether thyroid function could be associated with obesity phenotypes amongst euthyroid individuals. Materials and methods A cross-sectional analysis was conducted among healthy, euthyroid subjects. The study participants were chosen from the Tehran Thyroid Study (TTS). We analyzed 2988 euthyroid adults and classified them into four obesity phenotype groups: metabolically healthy normal weight (MHNW), metabolically healthy obese (MHO), metabolically unhealthy normal weight (MUNW), and metabolically unhealthy obese (MUO). The statistical differences between thyroid hormones between various obesity phenotypes according to age and sex was compared using analysis of covariance (ANCOVA). Results It was found that MHNW participants had higher levels of FT4 when compared with metabolically healthy or unhealthy obese subjects (P 0.05). Conclusion “Metabolically abnormality” was independently related to low normal FT4 levels in overweight/obese euthyroid individuals. There is a need for further research to understand how low FT4 levels are linked to metabolically unhealthy states in euthyroid individuals.

Keywords

• Thyroid function
• Free thyroxin
• Metabolic phenotype
• Obesity phenotype