Association between weight at birth and body composition in childhood: A Brazilian cohort study.

BACKGROUND AND AIM: Previous studies have shown that the association between birth weight and obesity later in life apparently follows a U-shaped curve. However, due to the continuous increase of mean birth weight in several countries worldwide, it is expected that higher birth weight will play a more important role as a risk factor for further obesity than low birth weight. This study investigated the association between birth weight and body composition of children in order to establish their relationship in an earlier period of life. STUDY DESIGN AND SUBJECTS: Prospective cohort study carried out from 1997 to 2006 in Jundiai city, Brazil, involving 486 children at birth and from 5 to 8 years of age. The following anthropometric measurements were determined: birth weight, weight, height, waist circumference and triceps skinfold thickness. Fat mass percentage, fat mass and fat-free mass were measured by electrical bioimpedance analysis by the 310 Body Composition Analyzer, Biodynamics(®). Five multiple linear regression models were developed considering waist circumference, triceps skinfold thickness, fat mass percentage, fat mass and fat-free mass as markers of body composition, and outcomes. RESULTS: Significant positive associations were observed between birth weight and waist circumference (p<0.001), triceps skinfold thickness (p=0.006), fat mass (p=0.007) and fat-free mass (p<0.001). Approximately 10% of the children presented excess body fat assessed by bioimpedance, and 27.6% of them had central adiposity (waist circumference ≥95th percentile). CONCLUSIONS: Intrauterine growth, assessed by weight at birth, was positively associated with body composition of children aged 5-8 years, indicating that those with the highest birth weight are more at risk for obesity, and probably to chronic diseases in adulthood.

Expression of the zinc transporters genes and metallothionein in obese women.

Research has investigated the participation of zinc transport proteins and metallothionein in the metabolism of this mineral. However, studies about the genetic expression of these proteins in obese patients are scarce. The study determined the expression of zinc transporter protein codifying genes (ZnT-1, Zip-1 and Zip-3) and of metallothionein in 55 obese women, aged between 20 and 56 years. The assessment of body composition was carried out using anthropometric measurements and bioelectrical impedance. Zinc intake was obtained by recording diet over a 3-day period, and the nutritional analysis was carried out using NutWin software version 1.5. The plasmatic and erythrocytary zinc were analyzed by atomic absorption spectrophotometry (λ=213. 9 nm). The determination of mRNA expression of the zinc transporter proteins and metallothionein was carried out using blood, using the RT-PCR method. The mean values of body mass index were 37.9±5.5 kg/m2. The average intake of zinc was 9.4±2.3 mg/day. The analysis of the zinc plasma concentrations showed values of 58.4±10.9 µg/dL. The mean values of zinc in the erythroytes were 38.7±9.1 µg/g Hb. The metallothionein gene had a higher expression in the blood, when compared to zinc transporters ZnT-1, Zip-1, and Zip-3 (p=0.01). The study shows that there are alterations in the biochemical parameters of zinc in obese patients assessed, as well as higher expression of the codifying gene metallothionein, when compared to the investigated zinc transporters.

Effect of zinc supplementation on thyroid hormone metabolism of adolescents with Down syndrome.

Studies have evidenced that zinc metabolism is altered in the presence of Down syndrome, and zinc seems to have a relationship with the metabolic alterations usually present in this syndrome. In this work, the effect of zinc supplementation on thyroid hormone metabolism was evaluated in adolescents with Down syndrome. A prospective study was carried out on 16 adolescents with Down syndrome (age: 10-19 years) who were randomized for treatment with 30 mg zinc daily for 4 weeks. Diet evaluation was accomplished y using a 3-day dietary record, and the analysis was performed by the NutWin program, version 1.5. Anthropometric measurements were performed for evaluation of body composition. The Zn-related nutritional status of the groups was evaluated by means of zinc concentration determinations in plasma and erythrocytes using the method of atomic absorption spectroscopy, and the thyroid hormone was obtained by radioimmunoassay. The diet of patients with Down syndrome, before and after the intervention presented reduced energy level and adequate zinc concentrations. Mean plasma zinc values were 59.2 +/- 13.2 and 71.0 +/- 21.9 microg/dL before and after the intervention, respectively. Erythrocyte concentrations of the mineral before supplementation, instead, were 51.5 microg/dL +/- 11.1 microg Zn/gHb, and at the end of the experiment, they were 42.9 +/- 8/5 microg Zn/gHb, with a significant statistical difference (p < 0.05). Serum concentrations of T(4) hormone before and after zinc supplementation were 1.26 +/- 0.20 and 1.54 +/- 0.63 pg/mL, respectively. Mean T(3) values before intervention were 2.47 +/- 037 pg/mL and, after supplementation, 2.25 +/- 0.67 pg/mL, without significant statistical difference (p > 0.05). Intervention with zinc showed to be effective in the stabilization of the concentrations of this mineral in plasma and erythrocytes, but had no influence on the metabolism of thyroid hormones.

Zinc nutritional status in adolescents with Down syndrome.

Studies have evidenced that zinc metabolism is altered in presence of Down syndrome, and zinc seems to have a relationship with the metabolic alterations usually present in this syndrome. In this work, the Zn-related nutritional status of adolescents with Down syndrome was evaluated by means of biochemical parameters and diet. A case-control study was performed in a group of adolescents with Down syndrome (n = 30) and a control group (n = 32), of both sexes, aged 10 to 19 years. Diet evaluation was accomplished by using a 3-day dietary record, and the analysis was performed by the NutWin program, version 1.5. Antropometric measurements were performed for evaluation of body composition. The Zn-related nutritional status of the groups was evaluated by means of zinc concentration determinations in plasma and erythrocytes, and 24-h urinary zinc excretion, by using the method of atomic absorption spectroscopy. The diet of both groups presented adequate concentrations of lipids, proteins, carbohydrates, and zinc. The mean values found for zinc concentration in erythrocytes were 49.2 +/- 8.5 microg Zn/g Hb for the Down syndrome group and 35.9 +/- 6.1 microg Zn/g Hb for the control group (p = 0.001). The average values found for zinc concentration in plasma were 67.6 +/- 25.6 microg/dL for the Down syndrome group and 68.9 +/- 22.3 microg/dL for the control group. The mean values found for zinc concentration in urine were 244.3 +/- 194.9 microg Zn/24 h for the Down syndrome group and 200.3 +/- 236.4 microg Zn/24 h for the control group. Assessment of body composition revealed overweight (26.7%) and obesity (6.6%) in the Down syndrome group. In this study, patients with Down syndrome presented altered zinc levels for some cellular compartments, and the average zinc concentrations were low in plasma and urine and elevated in erythrocytes.