Body composition indices align with thyroid variation in euthyroid Saudi adults: A cross-sectional study

Area of Science:

• Endocrinology
• Obesity Research
• Body Composition Analysis

Background:

• Obesity is linked to thyroid dysfunction, but studies in euthyroid adults using comprehensive body composition measures are limited.
• Sex-specific patterns in the obesity-thyroid function relationship require further investigation, particularly in Saudi populations.

Purpose of the Study:

• To investigate the associations between thyroid function markers (TSH, FT4, FT3) and body composition in euthyroid Saudi adults.
• To explore sex-specific differences in these relationships.

Main Methods:

• Cross-sectional study of 551 euthyroid Saudi adults (≥18 years, 59% men).
• Evaluation of anthropometric characteristics, body composition (bioelectrical impedance), and thyroid function (TSH, FT4, FT3).
• Correlation and logistic regression analyses were employed to assess associations and obesity risk.

Main Results:

• Low free thyroxine (FT4) levels were associated with increased odds of obesity (BMI and waist circumference).
• High thyroid-stimulating hormone (TSH) showed limited association with obesity overall, but was strongly linked to central obesity in women.
• Low FT4 was a prominent predictor of increased waist circumference in men. FT3 correlated positively with lean mass and negatively with fat percentage.

Conclusions:

• Greater adiposity is associated with higher TSH and lower FT4 levels in Saudi adults.
• The relationship between thyroid function and adiposity exhibits significant sex-specific patterns, with TSH-adiposity more pronounced in women and FT4-obesity inverse link stronger in men.