NUTRITIONAL STATUS IN EVOLUTIVE AGE: ASSESSMENT OF FAT MASS AMOUNT AND DISTRIBUTION AND OF THEIR SIGNIFICANCE IN METABOLIC DERANGEMENTS

Introduction: Chronic-degenerative diseases are nowadays in Italy the leading cause of death and requests for health care. Many of them, as indicated by the World Health Organization (WHO), are attributable to behaviors and lifestyles that are established from an early age, including improper eating habits, lack of physical activity and excess weight gain. Obesity is a condition characterized by an excessive accumulation of body fat, usually due to poor diets and a sedentary lifestyle, even if the etiology of obesity reflects a complex interaction between genetic, metabolic, environmental, cultural, socioeconomic, and behavioral factors. Previous studies have shown an association between adiposity, especially intra-abdominal adipose tissue, and hemodynamic/metabolic comorbidities in adults, however it is not clear in pediatric population. Aims of the study: to see the correlation between anthropometric measures and visceral fat assessed by ultrasonography in a large population of children; to see the clinical correlation of visceral fat accumulation in childhood obesity with respect to the development of metabolic derangements, compared to body mass index and waist circumference; to investigate the effects of visceral fat accumulation in developmental age; in particular we supposed that, like in adults, the increment of abdominal visceral fat, measured by ultrasonography, is associated with a worsened metabolic profile and with the increment of metabolic syndrome risk. Subjects and methods: 83 patients (58 females and 28 males), with age range 11-17 and mean age of 14,6 years. All the patients were subject to anthropometric measurements of weight, height, BMI, waist circumference (WC), skin folds. Patients were also subject to body fat assessment with air-displacement plethysmography, Dual Energy X-ray Absorptiometry (DEXA), Bioelectrical Inpedance Analysis (BIA) and Ultrasound: we considered measurements of abdominal subcutaneous skin-hepatic thickness (pre-hepatic AT), abdominal subcutaneous skin-muscle thickness (umbilical AT), intra-abdominal muscle-aorta thickness (Aortic AT). Each patient undergo to blood test evaluation including total cholesterol, high density lipoprotein cholesterol (HDL), low density lipoprotein cholesterol (LDL), triglycerides (TG), fasting blood glucose, insulin, renal function as creatinine and blood urea nitrate, hepatic function as glutamic pyruvic transaminase (GPT), glutamic oxaloacetic transaminase (GOT) and gamma glutamyl transpeptidase (GGT); metabolic syndrome was considered according to the International Diabetes Federation (IDF) criteria. Statistical analysis was conducted using SPSS-20, p value <0.05 was considered significant. Results and discussion: Our cohort of patients showed a significant difference of VAT between the two sexes, even after matching subjects for BMI, supporting that there is a definite gender difference in the age-related changes in whole-body fat distribution, especially in the abdominal fat tissues. The present study revealed a significant correlation between visceral fat and all the other anthropometric measures; regression analysis showed that among the measurements used in this study, the best predictor of visceral fat is waist to height ratio. With the data in our possess so far, we want to futher investigate this problem, in order to establish if assessment of visceral fat in children should be better done by an imaging modality and not indirectly from anthropometric measurements. In the present study, visceral fat assessment was observed to be closely associated with glucose metabolic risk factors including high fasting glucose and insulin resistance. This finding confirms that visceral adipose tissue is associated with glucose metabolism in evolutive age as well as in adult age, as already postulated. No significant correlations were found between visceral fat and hepatic function, except for γGT, demonstrating visceral fat to be an important predictor for hepatic functioning derangements. The association between visceral adipose tissue and lipid metabolism biomarkers is not so evident in our study. After adjustment for age, sex and BMI, we didn’t find any significant correlation between intra abdominal adipose tissue and lipid status. No significant relationship could be found between VAT and the presence of metabolic syndrome or its diagnostic criteria such as high triglycerides, high fasting glucose, low HDL, high blood pressure; a good correlation, even if not significant, was found with insulin resistance, suggesting once again visceral fat deposit to be involved in glucose derangements and in diabetes mellitus type 2 onset. The only significant correlation was found with VF to be a major risk to have high γGT, showing an odds ratio of 11,3. The results we have presented among children and adolescent are very similar to those presented for adults so far, showing probably similar pathways in the visceral fat accumulation and in its metabolic significance. Further studies will be held to better investigate the importance of visceral fat accumulation in evolutive age as a predictor for metabolic derangements.