ABSTRACT
CONTEXT: Visceral adipose tissue (VAT) is a strong predictor of carbohydrate metabolism disorders. Abdominal bioelectrical impedance analysis (A-BIA) is a simple method for the measurement of VAT and is a promising tool in screening and follow-up of abdominal obesity. However the role of A-BIA in dieting individuals has not been evaluated adequately in longitudinal follow-up studies. OBJECTIVE: The aim of this study is to determine the role of A-BIA in identifying the changes in metabolic predictors after diet and/or exercise therapy. DESIGN: All patients who sought weight loss treatment underwent baseline assessment and were prescribed a program of diet. After a mean follow-up of 3.2 months, data were analyzed. SUBJECTS AND METHODS: Ultimately, 103 participants who reported adhering to the diet, enrolled to the study. We tested associations between changes in body composition measures and changes in laboratory measures using correlations and multivariate linear regression analysis. RESULTS: Mean loss of body weight was 3.4±2.8 kg. All but waist-to-hip ratio, low-density lipoprotein cholesterol and high-density lipoprotein cholesterol levels changed significantly (p<0.001). Decreases in body weight, body mass index (BMI), and VAT level significantly correlated with decreases in fasting blood glucose, fasting insulin level, and HOMA-IR score (r=0.230-0.371). In multiple linear regression analysis changes in BMI and VAT significantly correlated with change in HOMA-IR score (F(7.93)=2.283, p=0.034, R2=0.147). CONCLUSION: Decreases in BMI and VAT, as determined by A-BIA, were predictors of changes in metabolic laboratory measures. A-BIA is useful for follow-up of patients receiving diet therapy for weight loss.
ABSTRACT
CONTEXT: Previous studies have associated overt/subclinical hypothyroidism and obesity but have failed to confirm a causative relationship between them. Confusion is even more for subjects with Hashimoto's Thyroiditis (HT). OBJECTIVE: In this study, we aimed to evaluate the fat distribution and metabolic profile of subjects with euthyroid HT as well as to establish an appropriate cut-off level of TSH for the development of metabolic syndrome (Mets) in both groups. PATIENTS AND METHODS: All subjects were euthyroid whether under levothyroxine replacement or not. We recruited 301 volunteers (99 with HT and 202 without thyroid autoimmunity). Together with some metabolic variables, we measured the waist circumference, hip circumference, neck circumference manually; the total body fat with a body composition analyzer; and the visceral fat/trunk fat percentage via abdominal bioelectrical impedance analysis. RESULTS: A significant positive correlation was established between TSH levels and insulin, fasting plasma glucose, HOMA-IR and body mass index (r=0.28; p<0.001; r=0.27; p<0.05: r=0.32; p<0.001: r=0.13; p<0.05 respectively). The prevalence of Metabolic Syndrome (Mets) was comparable in HT and control groups (27.3% vs. 30.7%; p>0.05). The prevalence of Mets was similar when HT subjects using levothyroxine or HT subjects with accompanying thyroid nodules were taken into consideration. Similarly, anthropometric and metabolic parameters were similar in both the HT group and the control group.We were unable to establish the TSH cut-off level by ROC analysis with desired sensitivity and specificity (AUC: 0.563 with 95% C.I. p=0.35; standard error 0.76). CONCLUSIONS: Although weight gain is frequently encountered in subjects with HT, such subjects with thyroid function tests in the euthyroid range have a similar prevalence of Mets and similar metabolic and anthropometric measurements compared to subjects without autoimmunity.
