Relationship between the change in body composition and the change in metabolic parameters of patients who are on diet therapy: Comparison of abdominal bioimpedance method with other measurement paramters

An increase in visseral adipose tissue (VAT) was correlated with type 2 diabetes mellitus, coronary heart disease and many other morbidities. Waist circumference (WC) and body mass index (BMI) which are well known simple indices of VAT, are unsatisfactory for predicting VAT level. Computer tomography (CT) and magnetic resonance imaging (MRI) which are the most sensitive methods for measuring VAT, are expensive and unwieldy. However a simple, non-invasive medical device, using bioelectrical impedance analysis (BIA) for the evaluation of VAT was developed in recent years. Studies, conducted with this device known as abdominal BIA, are generally correlation studies with CT and MRI and follow-up studies are very few. The basic aim of the current study was to investigate whether reduction of VAT measured by an abdominal BIA device AB-140 ViScan, is associated with the reduction of metabolic parameters such as fasting plasma glucose (FPG) level, fasting insulin level, HOMA-IR score and lipid levels after diet or/and exercise. And to investigate whether abdominal BIA device is superior to simple anthropometric measures and conventional BIA methods for indicating the change in metabolic parameters. Totally 274 individuals who didn't have diet or exercise at least for one year, and admitted to Başkent University Ankara Hospital, Endocrinology and Metabolism Department with desire of loosing weight were enrolled in the study. After the baseline assessment of the participants, they were treated with diet and just 103 participants who admitted for control visit, enrolled in the second assessment. The correlations between the change in body composition parameters and the change in laboratory parameters were analyzed. The participants in whom 81.6% of subjects were female (n=84) and 18.4% were men (n=19). The mean age of the participants was 41.8 (±10.5) years and mean BMI was found to be 29.9 (±5.0) kg/m2. After a mean period of 3.2 (1.9-4.4) months passed with diet, participants was found to be lost a mean of 3.4 (±2.8) kg. BMI, WC, hip circumference and neck circumference and all parameters which are measured with abdominal BIA and conventional BIA decreased significantly with diet (p<0.001), but waist-to-hip ratio didn't change (p=0.462). Fasting glucose, insulin and triglyceride levels and HOMA-IR score were significantly decreased (≤ 0.001), but significant decrease in LDL-C levels (p = 0.244) and significant increase in HDL-C levels (p=0.085) were not observed. Significant positive correlations were observed between a decrease in body weight, BMI, VAT level and a decrease in FPG levels, fasting insulin levels, HOMA-IR score (r=0.230-0.371). Furthermore decrease in VAT level was found to be significantly correlated with the decrease in the number of ATPIII criteria, but this correlation was not seen for decrease in body weight and BMI. Reduction in WC was only found to be correlated with the reduction in fasting blood glucose (r = 0.212), but the correlation between the reduction in WC and the decrease in HOMA-IR score (0.695) was only seen in men older than 40 years old. Beside that the correlations was found to be more strong for postmenopausal women (r=0.441-0.542) and for men older than 40 years old (r=0.695-0.876). The decreases in body weight, BMI, AB-140 measured VAT level and partially WC were found to be better parameters for predicting the change in metabolic laboratory parameters. Body weight, BMI and VAT level seems to be superior to the WC, but did not markedly superior to each other. However, unlike the others, the change in the level of VAD was found to be associated with a decrease in the number of ATPIII criteria, which makes this method more advantageous. We recommend the use of abdominal BIA device along with other measurement parameters for the follow-up of patients who are under diet and/or exercise, because of ease of use, operator independent feature, being harmless, feature of directly measuring VAT level, and the association with the change in especially HOMA-IR score and the number of ATPIII criteria and with the change in other metabolic parameters. However, this needs to be confirmed with prospectively evaluated follow-up studies in a more homogeneous group and with more cases. Key words: Abdominal bioelectrical impedance analysis, visceral adipose tissue, anthropometry, insulin resistance, metabolic syndrome