Indices of insulin resistance in paediatric obesity

Background: Paediatric obesity is associated with insulin resistance (IR), which increases risk of type 2 diabetes mellitus (T2DM) and cardiovascular diseases (CVD). Hyperinsulinaemic-euglycaemic clamp and minimal-model analysis frequently sampled intravenous glucose tolerance test (FSIVGTT) are used to assess IR, which are invasive, complex and expensive. Objective: To assess IR using the derived indices namely, homeostasis model assessment of insulin resistance (HOMAIR), fasting glucose-to-insulin ratio (FGIR), quantitative insulin-sensitivity check index (QUICKI), in obese children. Methods: Fifty obese children (cases) and 50 apparently healthy age-and gender- matched non- obese children (controls) were studied. Obese children with body mass index (BMI; Kg/m2) greater than 95th percentile and nonobese children with BMI between 5th to 95th percentile were included in the study. Results: Obese children had higher fasting insulin levels, HOMA-IR (p<0.001), FGIR (p<0.001) and QUICKI (p<0.001) when compared to controls; fasting blood glucose levels were comparable (p=0.170). A statistically significant correlation was observed between serum insulin and BMI, between insulin and all the derived indices and between the derived indices and BMI (p<0.001). HOMA-IR had more area under the curve (0.760) followed by FGIR (0.721) when compared to QUICKI (0.240). Conclusions: Obese children were normoglycaemic with IR. HOMA-IR was found to be a stronger predictor of IR when compared to FGIR and QUICKI in obese children

Antioxidant status in patients with metabolic syndrome as measured by ferric reducing ability of plasma (FRAP) assay

Background: Oxidative stress is involved in the athophysiology of diabetes and cardiovascular complications of metabolic syndrome. Endothelial dysfunction which is the key feature of metabolic syndrome and its vascular complication is intimately linked to insulin resistance. This relationship is partly due to oxidative stress. Methods: Twenty five patients with metabolic syndrome (mean age 47.3 ± 2.6 years, 13 males) diagnosed on the basis of National Cholesterol Education Programme/Adult Treatment Panel (NCEP/ATPIII) criteria along with 25 age and gender matched healthy controls (mean age 42.1 ± 1.8 years, 11 males) were studied. Malondialdehyde (MDA), as an index of changes in lipid peroxidation was estimated as thiobarbituric acid reactive substances (TBARS) along with plasma total antioxidant capacity as ferric reducing ability of plasma (FRAP). Results: A significant increase (p=0.001) in MDA levels in the study group was observed when compared to the control group, where as FRAP levels were decreased in the study group compared to the control group (p=0.001). Among the components of metabolic syndrome hyperglycaemia, hypertriglyceridaemia, hypertension and waist circumference positively correlated with MDA levels whereas hyperglycaemia, hypertriglyceridaemia and waist circumference correlated negatively with FRAP. Conclusions: The findings of the present study suggest the presence of oxidative stress in patients with metabolic syndrome which further increases the cardiovascular risk in these patients. Antioxidant therapy monitored with a simple assay like FRAP would definitely add to the existing measures like reducing abdominal obesity in preventing the cardiovascular sequelae and hence CVD risk in these patients

Body iron status and association with hyperinsulinaemia and hyperandrogenism in non-obese Indian women with polycystic ovarian syndrome

Background: Increased body iron stores, insulin and androgen levels have been reported in obese women with polycystic ovarian syndrome (PCOS). However, the status of iron and the influence of hormonal profile on iron status in non-obese women with PCOS has not been studied. The present study was thus designed to determine the iron status and hormones insulin and testosterone levels and their association with body iron status in non-obese women patients with PCOS. Methods: The present study included 33 non-obese women diagnosed as PCOS based on National Institutes of Health consensus 1990 criteria and 31 age-matched healthy women as controls. Height, weight, body mass index, fasting plasma glucose, iron status markers i.e., serum ferritin, iron, total iron binding capacity, insulin and testosterone levels were determined. Results: A significant increase in hormones insulin and testosterone levels (p<0.001) was found in patients with PCOS in comparison with controls. Similarly, a significant increase in serum ferritin levels was observed in PCOS patients compared to controls (p<0.05). A significant positive correlation was observed between serum insulin and testosterone levels (p<0.05). Similarly, a positive association was observed between serum testosterone and ferritin levels [p=0.007 odds ratio (OR) 7.0(1.715-28.568)]. Conclusions: The present study demonstrates that body iron stores, as reflected by serum ferritin concentrations, are increased even in non-obese PCOS patients. Androgen excess is associated with increased body iron stores in these patients with the possible additive effects of hyperinsulinaemia, through its perpetuating effect on increased androgens and iron-sparing effect of reduced menstrual losses