RESUMO
The age-dependent nutritional status and resting metabolism in overweight and obese children have been examined. The study included 625 children of 2.5-17 years old. Patients were divided into three groups: 1st--2.5-7 years old (n = 49), 2nd--8-12 years old (n = 204), 3rd--13-17 years old (n = 372). The diagnosis of overweight and obesity was based on CDC criteria: children with 85-94 BMI percentile according to age and gender had overweight, BMI 295 percentile--obesity. Anthropometry, bioelectric impedance analysis and indirect respiratory calorimetry were performed; lipid and carbohydrate parameters were measured. The fat mass percentages in children of studed groups were 41.3 ± 1.9, 39.8 ± 0.7 and 42.3 ± 0.4%, the mean percent of fat mass excess--163.6 ± 26.2, 113.7 ± 8.3 and 134.9 ± 8.2% respectively, p > 0.05. Prevalence of dyslipidemia in children increased with age: lipid metabolism disorders were revealed in 28.6, 49.0 u 53.2% children of the 1st, 2nd and 3rd groups respectively. The mean HDL level in the 1st and 2nd groups was significantly higher, and triglycerides--lower than in the 3rd group. The correlation of HDL level and breastfeeding duration (r1 = 0.94, p < 0.05) was found in the 1st group of children. Increased insulin level was revealed in 38.8% children in the 1st group (mean 12.8 ± 1.4 µIU/ml), 62.2% children in the 2nd group (21.1 ± 0.7 µIU/ml) and 64.8% children in the 3rd group (25.1 ± 0.9 µIU/ml); increased HOMA--in 36.7% (4.32 ± 0.6), 62.2% (4.65 ± 0.17) and 59.1% (5.56 ± 0.21) respectively. The negative correlation of insulin and HOMA level with breastfeeding duration (r1 = -0.38 and -0.37, respectively, p < 0.05) was found in the 1st group of children. Prevalence of hyperuricemia increased from 13% in the 1st group to 21.1% in the 2nd and 44.1% in the 3rd group. Prevalence and degree of resting metabolism changes increased with age and had tendency to the shift of proportion of energy-intensive substrates (fats and carbohydrates) to deceleration of carbohydrate oxidation (in 32, 50, 55.1% of children) and compensatory fat oxidation acceleration (8, 28.4 and 34.7% respectively). Mean fat oxidation rate levels significantly differed between groups and increased with age (48.38 ± 7.14, 54.29 ± 3.06 and 78.43 ± 2.89 g/day in children of the 1st, 2nd and 3rd groups respectively, p < 0.001). The mean level of carbohydrate oxidation rate in the 3rd group of children was lower than normal value (p < 0.01). Resting energy expenditure was lower in the 2nd and 3rd groups of children.
