In order to assess the validity of the weight per square of length ratio as an index of adiposity during the neonatal period, 37 premature infants (gestational age, mean ± SD, = 31.5 ± 1.1 weeks, birthweight, mean ± SD, =1.448 ± 147 g) were studied for weight, length and skinfold thickness at 5 sites (biceps, triceps, subscapular, suprailiac and quadriceps) during their stay in the Neonatal Unit of the University Hospital in Lausanne. The results show a significant correlation between the adiposity index and the sum of 5 skinfold thickness sites in premature infants. The adiposity index gives a fair estimate of the body fat mass during the postnatal growth in premature infants.

RESUMENOBJETIVO: Determinar las características antropométricas, bioquímicas y sus relaciones en niños con obesidad exógena. MATERIAL Y MÉTODOS: Se estudió 50 niños y adolescentes (25 varones y 25 mujeres) comprendidos entre los 6 a 18 años, que presentaban un índice de masa corporal (IMC) por encima del 95 percentil para la clasificación de Must y col. A todos se les tomó los pliegues tricipital y subescapular y la cincunferencia de cintura; asimismo se dosó por venopuntura colesterol total (CT) y triglicéridos (TG).. Los niveles diagnósticos para determinar dislipidemia fueron 200 mg/dL para CT y 100 mg/dL en menores de 10 años, y 130 mg/dL en mayores de 10 años para TG. Al conjunto de niños se los dividió en dos grupos, de acuerdo al valor encontrado del 50 p para el IMC, PT y CC. En cada grupo se determinó el promedio y su desviación estándar, así como la correlación de Pearson, para los indicadores antropométricos, bioquímicos. RESULTADOS: El 32,6% y 55,6% de niños obesos presentaron hipercolesterolemia e hipertrigliceridemia, respectivamente y 26,1% tuvo dislipidemia mixta. La diferencia de promedio entre los dos grupos presentó significación estadística (p< 0,05) para los indicadores antropométricos; lo contrario sucedió para los bioquímicos. CONCLUSIONES: El mayor problema que presenta el niño obeso es la hipertrigliceridemia. La obesidad y las dislipidemias pudieran ser factores de riesgo independientes y no necesariamente uno consecuencia del otro. Palabras clave: Obesidad; salud infantil; hipertrigliceridemia; hipercolesterolemia. INFANTILE OBESITY: ANTHROPOMETRIC AND BIOCHEMICAL CHARACTERISTICS SUMMARYOBJECTIVE: To determine both anthropometric and biochemical characteristics and relationship in children with exogenous obesity. MATERIAL AND METHODS: Fifty 6 to 18 year-old children and adolescents (25 male and 25 female) with body mass index (BMI) over 95 percentile according to Must et al classification were studied. Studies included triceps and subscapular skinfolds, waist circumference, serum total cholesterol (TC) and triglycerides (TG). Dyslipidemia was determined with TC 200 mg/dL and 100 mg/dL in children less than 10 year-old and TG 130 mg/dL for persons above 10 years of age. Children were divided in two groups according to 50 p values for BMI, TS and WC. Average and standard deviation were determined in each group, as well as Pearson correlation for both anthropometric and biochemical indicators. RESULTS: A total of 32,6% and 55,6% of obese children and adolescents presented hypercholesterolemia and hypertriglyceridemia, respectively; 26,1% had mixed dyslipidemia. Statistic significant difference (p< 0.05) was found for anthropometric indicators, as opposed to biochemical indicators. CONCLUSIONS: Hypertriglyceridemia was the main problem in obese child. Obesity and dislipidemias could be independent risk factors and not necessarily consequence of the other.

Changes in the rate of growth and adiposity index (Quetelet index), calculated as weight/(length)², kg/m², were monitored from birth to 3 years in 19 premature babies (post-conceptional age 31.2 ± 2 weeks) who were subjected during rapid growth (16 ± 4 g/kg·day) to initial metabolic balance studies in the first weeks of life. These studies showed that the rate of fat accretion in these infants (3.3 ± 0.9 g/kg·day) was substantially greater than that observed in fetuses of the same gestational age (2 g/kg·day) but the adiposity index was lower (9.6 ± 1 kg/m²) than intrauterine values (11 kg/m²). Since at 6 months of age (corrected for gestational age at birth) the adiposity index was close to normality (103% of standard), the greater rate of fat accretion in early life contributed to progressively restore total body fat in premature babies. It is concluded that despite substantial fat deposition during the first weeks of life, the future evolution of these premature babies is favourable as judged from the normalization of adiposity index within the first 2 years of life.