Risk Factors, Complications and Characteristics of Metabolic Syndrome in Obese Children and Adolescents. Summary of the Doctoral Thesis

Abstract

Introduction. Public health research indicates that the prevalence of obesity is rapidly increasing not only among adults, but especially is rapidly increasing among adolescents, slightly less among young children. In Latvia, the prevalence of overweight and obesity is higher in seven-year-old boys compared to girls, 23.7 % and 21.8 %, respectively. However, for girls, this proportion has gradually increased since 2008 from 18.3 % to 21.8 %. Children and adolescents with obesity are at risk of early cardiovascular disease, arterial hypertension, dyslipidemia, metabolic syndrome, insulin resistance, type 2 diabetes mellitus, various types of tumors, orthopedic problems, serious psychological and neurological problems, and other health problems. Metabolic syndrome has a special role in adulthood and is associated with a higer risk for type 2 diabetes mellitus and cardiovascular disease. However, the definition, diagnostic criteria, risk factors, prevention, and treatment of metabolic syndrome in children and adolescents have not yet been standardized.Aim. To study the risk factors, complications and features of metabolic syndrome in children and adolescents with obesity.Materials and methods. The study included 198 children according to inclusion and exclusion criteria, including 181 children with obesity and 17 children with normal body weight. In the first phase of the study, the children were divided into groups according to weight and age, study group I – children 10 years and older with obesity, study group II – children under ten years with obesity, control group – children with normal body weight. In this study phase, prenatal and postnatal obesity risk factors were evaluated, and obesity complications were screened. The second phase of the study evaluated metabolic syndrome as defined by the International Federation of Diabetes at 10 years of age, only in children in study group I (n = 143). All research data were summarized in an Excel database and analyzed using RStudio V.1.4.1103. Differences were considered statistically significant if the significance level was p < 0.05.Results. There were no statistically significant differences regarding prenatal obesity risk factors, large birth weight (p = 0.530), maternal weight gain during pregnancy (p = 0.787), and a positive family history of type 2 diabetes mellitus (p > 0.999) between obese and normal weight children. No statistically significant differences were found in the duration of breast feeding (p = 0.120) between obese and normal weight children. A statistically significant difference was observed in the study groups only for the postnatal obesity risk factor – parental obesity (p = 0.004). Children with obesity had a high prevalence of parental obesity in study group I and group II, 79.8 % and 63.0 %, respectively, compared to children of normal weight. In children of normal weight, parental obesity was detected in only 33.3 % of the cases. Screening for obesity complications has shown statistically significant changes in cardiovascular disease, insulin resistance, and other biochemical parameters in obese children compared to normal weight children. In study group I, the median systolic blood pressure 123.0 (IQR 116.0; 132.0) and the median diastolic blood pressure 78.0 (IQR 71.5; 83.0) were significantly higher compared to controls, with the median systolic blood pressure 115.0 (IQR 110.0; 120.0) and the median diastolic blood pressure 70.0 (IQR 65.0; 76.0) (p = 0.012). No child had an elevated total cholesterol above 5.2 mmol/l in the control group, compared to 8.8 % in study group I. Children with obesity had a statistically significant higher median HOMA-IR in both study group I and group II, 3.9 (IQR 2.6; 5.6) and 2.3 (IQR 1.5; 3.4) in control group, respectively. The median HOMA-IR for children of normal weight was 1.1 (IQR 0.8; 2.1) (p < 0.001).In children in study group I, metabolic syndrome was diagnosed in 21 % (n = 30) according to the criteria developed by the International Federation of Diabetes. The incidence of metabolic syndrome in the study population increased with age, with 17.1 % of children diagnosed with metabolic syndrome between aged 10 to 16 years and 38.5 % of children over 16 years of age diagnosed with MS. Children with metabolic syndrome had significantly higher median weight (p < 0.001) and lower insulin sensitivity (p = 0.039) compared to children without metabolic syndrome. There was no evidence of prenatal risk factors for obesity such as large birth weight (p = 0.145), excessive weight gain during maternal pregnancy (p = 0.625), a positive family history of type 2 diabetes mellitus (p = 0.519) had an effect on the development of metabolic syndrome. The postnatal risk factor for obesity – the duration of exclusive breastfeeding also did not affect the development of metabolic syndrome (p > 0.999). The risk of metabolic syndrome in children increased with increasing body mass index, and the risk of metabolic syndrome was 11.13 times higher in the case of paternal obesity. Conclusions. Risk factors for cardiovascular disease and type 2 diabetes mellitus have been observed early in obese children. Children with obesity over 10 years of age had higher blood pressure, elevated total cholesterol and increased insulin resistance and HOMA-IR ratio. The diagnosis of metabolic syndrome was confirmed in almost a quarter of the pediatric study population. The risk of metabolic syndrome increased significantly with both the degree of obesity and the level of parental obesity.