Hemoglobin A1c in the Screening of Obesity-Related Diseases in Children and Adolescents

ABSTRACT

PURPOSE: The aim of this study is to investigate differences in hemoglobin A1c (HbA1c) levels according to degree of obesity, clinical findings on HbA1c 5.7% and factors affecting HbA1c in growing children and adolescents. METHODS: 168 children and adolescents (M/F, 93/75; age, 10.2+/-2.6 years) who visited an obesity clinic were included in the study. Participant's body mass index (BMI), percent weight for height (PWH), height z score (HTZ), weight z score (WTZ), and BMI z score (BMIZ) were calculated. Their blood glucose, insulin, total cholesterol, triglyceride, HDL-cholesterol (HDL-C), aspartate aminotransferase (AST), alanine aminotransferase (ALT), insulin-like growth factor-1 (IGF-1) and IGF binding protein-3 (IGFBP-3) levels were checked. Confirmed cases of diabetes and endocrine disease were excluded. Participants were divided into two groups based on whether their HbA1c levels were higher or lower than 5.7%. The difference in HbA1c between the groups based on the BMIZ 2 and PWH 20 were analyzed. A correlation analysis involving HbA1c and metabolic parameters was conducted, and factors contributing to HbA1c were evaluated through a regression analysis. RESULTS: HbA1c was higher in subjects with impaired fasting glucose (5.3+/-0.3, 5.4+/-0.2; P = 0.018). HbA1c and the homeostasis model assessment of insulin resistance (HOMA-IR) were not significantly different in the groups based on BMIZ 2.0. Based on PWH 20, HOMA-IR was significantly different (1.8+/-0.7, 2.3+/-1.1; P < 0.05), although HbA1c was not. Levels of TG (107.4+/-69.4, 154.1+/-77.7; P = 0.006), HDL-C (53.6+/-11.9, 47.4+/-6.6; P = 0.024), AST (29.7+/-11.4, 39.2+/-24.6; P = 0.004), and ALT (32.4+/-32.0, 53.9+/-58.8; P = 0.014) indicated significant differences between the groups. There were positive correlations between HbA1c and height, weight, BMI, gender, AST, ALT, glucose, and HOMA-IR, but no significant correlation with HTZ, WTZ, and BMIZ. The contributing factors for HbA1c were gender, ALT, BMI, and IGFBP-3. CONCLUSIONS: HbA1c level is associated with metabolic syndrome parameters, but is not correlated with degree of obesity. Along with HbA1c, other factors should be considered in evaluating the risk of complications related to obesity in children and adolescents.