RF23 | PSAT266 The Relationship Between Thyroid Function and Body Mass Index, Leptin, Adiponectin, and Insulin Resistance in Euthyroid Subjects Before and After Laproscopic Sleeve Gastrectomy

Abstract The relationship between obesity and thyroid function tests (TFT) has been studied in the past decades with increasing interest, however, studies have been inconsistent . The objectives of this study were to examine the effect of weight loss induced by laparoscopic sleeve gastrectomy(LSG) on TFT in obese euthyroid subjects and to correlate that with the changes in serum leptin, adiponectin, and insulin resistance.55 euthyroid obese subjects(BMI > 30) and 52 non-obese (BMI < 30), age-matched controls were recruited at baseline. We measured body weight, BMI, body composition, thyroid-stimulating hormone (TSH), Free T4 (FT4), Free T3(FT3), fasting leptin, adiponectin. Insulin resistance was quantified by HOMA-IR. Data are presented as mean ± SEM. The same parameters were repeated at 3- and 6-months in the obese group. Obese subjects had significantly higher TSH compared to non-obese subjects, 2.7 ±0.18 V.s 1.7±0.13 (normal range 0.27-4.2 mIU/L . Mean FT3 was 3.9± 0.1pmol/L (normal 3.1-6.8) in obese subjects compared to 5.0 ± 0.1 pmol/L in the non-obese controls, respectively, P value 0.001, however, FT4 (Normal 12-22 pmol/L) was similar in the two groups.Repeated measures ANOVA showed significant reduction in body weight from 140±26.5 kg at baseline to 115.8 ± 22.3 kg at 3 months, P < 001, and 104.2 ± 21.1 kg at 6 months, P<0.001, respectively. Serum TSH (N=48) reduced from 2.6 ±0.86 at baseline, to 2.0 ± 0.85 at 3 months, P = 0.06, and was 2.2± 0.78, at 6 months, P=0.23, in comparison with baseline, N=47). Free T3 reduced from 3.7.0 ± 0.41 pmol/L at baseline to 3.2 ±0.4 at 3 months (P < 0.9) and increased to 3.9± 0.53 at 6 months, P < 0.33. Changes in FT4 were not significant at 3 and 6 months, respectively. HOMA-IR reduced within 6 months and correlated with baseline FT3 .Serum leptin (N=38) significantly reduced from 25.9 ng/ml at baseline to 17.5 ng/ml at 3 months(p=0.037) to 15.2 ng/ml at 6 months, respectively, P < 0.011 compared to baseline. On the other hand, serum adiponectin (N=22) significantly increased from the baseline value of 9.2 ng/ml to 12.4 ng/ml at 3 months (p=0.001) and 16.6 ng/ml at 6 months(p<0.001 from baseline). TSH and Free T3 tend to decrease within 6 months following weight loss with LSG in obese subjects . Serum leptin significantly decreased and serum adiponectin significantly increased following LSG, however, there were no correlations between the changes in these adipose tissue markers and TFTs . We speculate that the changes in TSH and FT3 in obese euthyroid subjects may be due to the influence of the obesity and are unlikely to be causative, since they tend to reverse after weight loss, however, further studies on larger numbers of patients are needed to further explore the relationship between obesity and TFTs. Presentation: Saturday, June 11, 2022 1:00 p.m. - 3:00 p.m., Sunday, June 12, 2022 12:48 p.m. - 12:53 p.m.