by Dr. Meenakshy Varier on  April 5, 2017 at 2:19 PM Health Watch
  • Bariatric surgery is an effective treatment for obesity and thyroid hormones play a vital role in regulating body weight.
  • Obese people who have higher levels of thyroid hormone triiodothyronine (T3) experienced significant weight loss after bariatric surgery.
  • Weight loss was not affected by preoperative levels of throxine (T4) and thyroid stimulating hormone (TSH).

Weight loss is more prominent after bariatric surgery, in patients who have higher levels of the thyroid hormone triiodothyronine (T3).

"Bariatric surgery is the most effective treatment for obesity, and thyroid function plays a central role in body weight regulation. However, the predictors of weight loss after bariatric surgery have remained largely unknown," said lead author João Sérgio Neves, M.D., Resident of Endocrinology at the São João Hospital and Invited Assistant of the Department of Surgery and Physiology at the Faculty of Medicine of the University of Porto, in Portugal.
Higher Thyroid Hormone Levels Trigger Significant Weight Loss Post-Bariatric Surgery

If obese patients fail to lose weight through diet and exercise, bariatric surgery is the best option.

There are many types of bariatric surgery. Some surgeries limit the amount of food taken, while others affect the digestion and absorption of food. There are some complications like infections, blood clots and hernias, associated with bariatric surgery.

"Our study shows that patients with higher T3 levels lose more weight after bariatric surgery. Our results underscore the future potential for thyroid hormone treatment after bariatric surgery," Neves said.


For the study, 649 patients with morbid obesity and normal thyroid function were evaluated. The patients had an average preoperative body mass index (BMI) of 44.65 kg/m2.

Around 84.3% of patients were women and their average age was 41.8 years.

All patients had undergone bariatric surgery.

Exclusion criteria :
  • patients with history of thyroid disease, being treated with levothyroxine or antithyroid drugs
  • patients with thyroid stimulating hormone (TSH) or free thyroxine (T4) outside the reference range
The researchers analyzed the participants' preoperative age, sex, thyroid function (TSH, free T3, free T4), lipid profile, fasting glycemia, hemoglobin (Hb) A1C, BMI, waist-to-hip ratio, blood pressure, diabetes diagnosis, dyslipidemia and hypertension; type of surgery and percentage of excessive body weight loss one year after surgery.

Weight loss was not significant in patients with preoperative levels of TSH and free T4, and variation within the reference range of free T3.

But, in 11.4% of patients whose free T3 was higher than the reference range (free T3 above 3.71 picograms per milliliter), there was significant weight loss compared to patients with normal free T3 (76.6% vs 65.4%).

Patients with high free T3 were younger in age. There was no significant difference in sex, BMI, surgery type, diabetes, or hypertension or dyslipidemia status.

After adjusting for variables such as age, sex, BMI, surgery type, TSH and free T4 levels, the loss of excess weight in the group with high free T3 was significant.

The study was presented at ENDO 2017, the annual meeting of the Endocrine Society, in Orlando, Florida.


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Source: Medindia

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