Association of acanthosis nigricans and skin tags with insulin resistance

Insulin resistance is a metabolic disorder in which target cells fail to respond to normal levels of circulating insulin. Insulin resistance has been associated with presence of acanthosis nigricans and acrochordons. It is known that early diagnosis and early initial treatment are of paramount importance to prevent a series of future complications. These dermatoses may represent an easily identifiable sign of insulin resistance and non-insulin-dependent diabetes.

Acanthosis nigricans as a clinical marker to detect insulin resistance in Caucasian children from West Virginia

The accuracy of acanthosis nigrcans (AN) as a dermatological clinical marker to predict insulin resistance (IR) has not been well established in children. A cohort of obese Caucasian children was prospectively recruited. Demographic data, body mass index values, and laboratory data were compared for the presence or absence of AN. A total of 76 children participated. In all, 46 (60.5%) children had AN, and 34 (44.7%) children were positive for IR (>3.16); 25 (32.9%) children were positive for both AN and IR. Sensitivity, specificity, positive and negative predictive values, and accuracy level for AN to detect IR in the obese children who participated in this study were 73.5%, 50%, 54.3%, 70%, and 49%, respectively. The correlation between insulin and fasting glucose levels in AN-negative or AN-positive patients was low (R (2) = 13% to 17%). Acanthosis nigricans was only a surrogate marker for IR. It is concluded that IR should be examined in every obese West Virginian child irrespective of his or her AN status.

Insulin Resistance during Puberty in Non-obese Japanese Children

We examined whether non-obese Japanese children without diabetes exhibited insulin resistance during puberty. The study subjects were 201 Japanese school students, consisting 95 males and 106 females, aged 11.5 ± 2.6 yr. None of the subjects were obese, with the mean percent of overweight being 0.7 ± 10.5%, or had diabetes at the time of the study. Overnight fasting plasma values of insulin (FIRI) and HOMA-R were measured, with concomitant measurement of the plasma glucose (FPG) levels. The mean FPG, FIRI and HOMA-R values were 89.6 ± 7.3 (70–109) mg/dl, 9.0 ± 3.6 (1.7–24.4) µU/ml and 2.0 ± 0.9 (0.3–5.2), respectively. The mean FIRI value was significantly higher in females than in males (8.3 ± 3.4 vs. 9.6 ± 3.7 µU/ml, p=0.0060). The FIRI and HOMA-R values of the pubertal students were significantly higher compared with those of the prepubertal students (FIRI, 10.0 ± 3.4 vs. 6.5 ± 2.8 µU/ml; HOMA-R, 2.3 ± 0.8 vs. 1.4 ± 0.7; p<0.0001 for both). Similar trends were observed between the two genders. The mean FIRI levels and HOMA-R values were positively correlated with age (FIRI, r=0.280, p<0.0001; HOMA-R, r=0.300, p<0.0001). In conclusion, we demonstrated that the FIRI and HOMA-R values were significantly associated with pubertal development in non-obese Japanese children without diabetes, consistent with the results of studies in white and black children.

Criteria for medical intervention in obese children: a new definition of 'obesity disease' in Japanese children

The Committee of the Japan Society for the Study of Obesity reported the new criteria for 'obesity disease' for Japanese adults in 2000. We defined the criteria for the diagnosis of obesity in children with medical problems, corresponding to the 'obesity disease' criteria in adults. Obesity in childhood was defined as follows: percentage of overweight (POW) and body fat exceeded the criteria. 'Obesity disease in childhood' was defined as obesity associated with health or medical problems, and with indications for medical intervention. Medical problems with indications for immediate intervention were grouped as A problems, which consisted of (i). hypertension; (ii). sleep apnea or hypoventilation; (iii). Type 2 diabetes mellitus or impaired glucose tolerance; and (iv). increased waist circumference or accumulation of visceral adipose tissue. Metabolic derangements or equivalent associated with obesity were grouped as B problems: (i). liver dysfunction; (ii). hyperinsulinemia; (iii). hypercholesterolemia; (iv). hypertriglyceridemia; (v). low serum high-density lipoprotein cholesterol; (vi). acanthosis nigricans, and (vii). hyperuricemia. Obese children over 5 years of age with following conditions were diagnosed as 'obesity disease in childhood': (i). any 'A problem', (ii) POW >or= 50% and any 'B problem', or (3) POW < 50% and more than one 'B problem' or equivalent. We decided to take physicosocial problems related to obesity into consideration as the criteria. The resultant criteria are proposed by the Committee for Research of Appropriate Body Build in Children*.

Fasting plasma ghrelin levels are negatively correlated with insulin resistance and PAI-1, but not with leptin, in obese children and adolescents

Ghrelin is a novel growth hormone-releasing peptide isolated from human and rat stomach that induces weight gain by increasing food intake and reducing fat utilization. Although recent data indicate that ghrelin is downregulated in human adult obesity, the characteristics of human obesity are heterogeneous, especially in children and adolescents, and depend on the distribution of subcutaneous and visceral fat tissue. We measured fasting plasma ghrelin concentrations by radioimmunoassay in 49 obese Japanese children and adolescents (38 boys and 11 girls; mean age 10.2 +/- 2.8 years; BMI 28.0 +/- 4.5 kg/m(2), percent overweight 56.0 +/- 20.7%), and analyzed associations of their ghrelin concentrations with their body composition, insulin resistance, and adipocytokine concentrations. Fasting plasma ghrelin levels were negatively correlated with BMI and waist circumference, but not with percent overweight or percent body fat, whereas fasting leptin levels were positively correlated with all of the following parameters: BMI, waist circumference, percent overweight, and percent body fat. Plasma ghrelin levels were negatively correlated with fasting immunoreactive insulin, homeostasis model assessment insulin resistance index, and quantitative insulin sensitivity check index values. There was no correlation between plasma ghrelin and leptin, but ghrelin was negatively correlated with the PAI-1 concentrations. The results suggest that the downregulation of ghrelin secretion may be a consequence of higher insulin resistance associated with visceral fat accumulation and elevated PAI-1 concentrations, and not a consequence of total body fat accumulation associated with elevated leptin concentrations.