Relationship of thyroid function with body mass index and insulin-resistance in euthyroid obese subjects.

BACKGROUND AND AIMS: It is recognized that overt thyroid dysfunction is associated with weight changes, but the influence of a minor alteration of thyroid function remains unclear. This study aimed to further investigate the relationship between obesity and thyroid function and to examine the possible role of insulin resistance on the hypothalamic-pituitary- thyroid axis. METHODS AND RESULTS: Serum TSH and free T4 (FT4) levels, anthropometric and metabolic parameters were evaluated in 581 obese patients. In all patients TSH values progressively increased according to the severity of obesity and were positively correlated with body mass index (p=0.001, r=0.13) and waist circumference (p=0.02, r=0.11). Patients with insulin resistance showed higher TSH (1.8±1.0 vs 1.6±0.9 µUI/l; p=0.03) and lower FT4 levels (13.8±2.3 vs 15.0±2.2 pmol/l; p<0.001), as compared with patients with normal insulin sensitivity. Moreover, TSH was positively correlated with fasting insulin (p<0.001, r=0.152) and homeostasis model assessment of insulin resistance (HOMA-IR; p<0.001, r=0.148), and negatively correlated with Quantitative Insulin Sensitivity Check Index (QUICKI; p<0.001, r=-0.148); FT4 was negatively associated with fasting insulin (p<0.001, r=-0.287) and HOMA-IR (p<0.001, r=-0.295), and positively associated with QUICKI (p<0.001, r=0.295). CONCLUSIONS: A relationship between thyroid function and overweight/ obesity condition seems to exist, mainly influenced by insulin resistance. Whether variations in TSH and/or thyroid hormones, within a normal range, can influence body weight or whether obesity per se can alter thyroid function cannot be stated so far. Further studies are needed to assess the link between thyroid function and body weight, by considering not only changes in thyroid hormones, but also body fat distribution, obesity duration and low-grade inflammation.

Metabolic parameters after BioEnterics Intragastric Balloon placement in obese patients.

BACKGROUND: BioEnterics Intragastric Balloon (BIB) is a non-invasive, temporary and relatively safe procedure shown to be effective in the short-term treatment of obesity. Nowadays, BIB does not show convincing evidence of significant long-term weight loss, as compared with conventional management, and data regarding changes in metabolic and nutritional parameters are lacking. METHODS: Forty obese patients [11 males, 29 females, age 36.65+/-10.6 yr, body mass index (BMI) 44.9+/-8.9 kg/m2] were evaluated before and 3 and 6 months after BIB placement by assessment of anthropometric and biochemical parameters as well as nutritional habits. RESULTS: Patients showed a significant reduction in weight (-13.2+/-6.5%), BMI (-13.2%), waist circumference (-6.5 cm), and percentage of fat mass (-19.5%), but not fat-free mass. A significant improvement in insulin sensitivity but not in lipid pattern was seen. After BIB insertion, a significant reduction in caloric intake was paralleled by a redistribution of nutrients; in particular, increased lipid (12.8%) and decreased carbohydrate (-11.7%) percentage, but not absolute intake was observed. CONCLUSION: These data show that BIB improves anthropometric parameters, with reduction of fat mass and preservation of fat-free mass, as well as insulin resistance, but not other metabolic features. The observed change in dietary habits, with a relative increase in lipid intake, once BIB is removed, might favor body weight regain and impact negatively on body weight composition and the other traits of the metabolic syndrome.