OBESITY AND THYROID FUNCTION IN OBESE WOMEN: A PILOT STUDY.

Background: Obesity is an expanding pathology in the world and in Tunisia. We conducted this study to assess the thyroid function in a population of obese women and to investigate the relationship of thyroid status parameters with clinical and metabolic parameters.

Methods: This was a cross-sectional retrospective study about 50 obese women. We collected body mass index (BMI), waist circumference (WC), serum free thyroxin (FT4) and thyroid stimulating hormone (TSH) levels, fasting glycemia (FG), baseline insulinemia, lipid profile, liver function, and body composition, assessed by bioelectrical impedancemetry. We assessed insulin resistance and pancreatic activity by calculating the Homeostasic Model Assessment for Insulin Resistance (HOMA-IR) and the Homeostasic Model Assessment to quantify Beta-cell function (HOMA-B) respectively.

Results: The mean BMI and WC were 41,2±9,3 kg/m² and 120±17,7 cm, respectively. The mean body fat percentage (BF) was 43,4±7,1%. The mean FT4 and TSH levels were 16,6±4,7 pmol/L and 2,4±1 IU/L, respectively. Two patients had subclinical hypothyroidism. Glycoregulation abnormalities were noted in 54%. The mean insulinemia, HOMA-IR and HOMA-B were 23,4±14,8 mIU/L, 6,5±5,1 and 230,4±162,1 respectively. Most patients had insulin resistance (96%). TSH was not correlated with cardiometabolic risk parameters nor with BF. FT4 was correlated with age (r=-0,3, p=0,017), FG (r=-0,29, p=0,019), insulinemia (r=-0,42, p=10-3), cholesterol (r=0,24, p=0,04) and high-density lipoprotein (r=0,24, p=0,002). It was not correlated with BF (r=-0,14, p=0,32).

Conclusion: In our population of obese women, FT4 seems to be more correlated than TSH with cardiometabolic risk parameters.