Thyroid-stimulating hormone, leptin and insulin resistance in patients with obesity after bariatric surgery

Abstract

BACKGROUND: The function of the thyroid gland effects on obesity and comorbidities. It has been proven for bariatric surgery to be the most effective in obesity treatment. AIM: to evaluate the dynamics of body weight, thyroid status, leptin and insulin resistance in obese patients after bariatric surgery. MATERIALS AND METHODS: 74 obese patients were observed after bariatric surgery (sleeve gastrectomy – 42, gastric bypass - 32); initial body mass index (BMI), thyroid stimulating hormone, free T4, fasting plasma leptin, insulin and glucose were estimated; the insulin resistance index HOMA-IR was calculated. The dynamics of body weight was estimated by BMI and the excess BMI loss (% EBMIL). After 3 years of follow-up, 48 patients were examined. RESULTS: Subclinical hypothyroidism (SH) was detected in 36.5% of patients with high degrees of obesity. A correlation was found between BMI and TSH level (R=0.5; p=0.01). HOMA-IR was increased in most patients with obesity of the II and III degree (4.8±1.9 ng / ml). In the SH group, the leptin level was significantly higher than in the group with a normal TSH level of 43.0±7.3 ng / ml and 33.2±4.6 ng / ml (p=0.004). Among patients with initial SH, spontaneous reduction of TSH levels occurred in 45% patients 3 years after surgery. CONCLUSIONS: Postoperatively, the BMI decrease was associated with the decrease of TSH, leptin and HOMA-IR. The data obtained may reflect the effect of adipose tissue on the functional state of the thyroid gland in patients with high degrees of obesity after bariatric surgery. This seems to be extremely important for maintaining body weight.

Keywords

• obesity
• thyroid stimulating hormone
• leptin
• insulin resistance
• bariatric surgery