Epidemiology of leisure-time physical activity: a population-based study in southern Brazil.

We aimed to measure the prevalence of physical inactivity (PI) during leisure time and to identify variables associated with it in a southern Brazilian adult population. A population-based cross-sectional study was carried out, covering a multiple-stage sample of 1,968 subjects aged 20-69 years. Weekly participation in leisure-time physical activity was addressed.

Indices of whole-body and central adiposity for evaluating the metabolic load of obesity.

Background: To assess the relative metabolic load or risk imposed by fatness, fat mass (FM) is commonly expressed as a proportion of weight (% fat), while central adiposity is assessed using the ratio of triceps (TRI) to subscapular (SUBS) skinfolds. The statistical validity of these indices, defined as independence of the index from its denominator, has received inadequate evaluation.

Objective: To critically examine commonly used obesity indices, and to propose more appropriate approaches.

Assessing the acceptability and feasibility of the MEND Programme in a small group of obese 7-11-year-old children.

Background And Aims: An uncontrolled, pilot study to evaluate feasibility and acceptability of a new community based childhood obesity treatment programme.

Methods: The mind, exercise, nutrition and diet (MEND) programme was held at a sports centre, twice-weekly, for 3 months. The programme consists of behaviour modification, physical activity and nutrition education.

Composition of the fat-free mass in obese and nonobese children: matched case-control analyses.

Objective: Most body composition techniques assume constant properties of the fat-free mass (FFM), such as hydration, density and mineralisation. Previous studies suggested that FFM composition may change in childhood obesity; however, this issue has not been investigated in detail.

Aim: To compare FFM composition in obese and nonobese children.

Fetal and infant head circumference sexual dimorphism in primates.

Studies have shown that after controlling for the effects of body size on brain size, the brains of adult humans, rhesus monkeys, and chimpanzees differ in relative size, where males have a greater volume of cerebral tissue than females. We assess whether head circumference sexual dimorphism is present during early development by evaluating sex differences in relative head circumference in living fetuses and infants within the first year of life. Head circumference is used as a proxy for brain size in the fetus and infant.

Multiscale simulations of carbon nanotube nucleation and growth: electronic structure calculations.

Several first-principles surface and bulk electronic structure calculations relating to the nucleation and growth of single-wall carbon nanotubes are described. Density-functional theory in various forms is used throughout. In the surface-related calculations, a 38-atom Ni cluster and several low-index Ni surfaces are investigated using pseudopotentials and plane-wave expansions.

Prematurity and reduced body fatness at 8-12 y of age.

Background: Increasing evidence suggests that body composition, an important factor influencing morbidity and mortality in adult life, might be programmed by early growth and nutrition. Children born preterm remain shorter and lighter than their term-born peers during childhood, but it is unclear whether the size difference is associated with altered body composition.

Objective: We tested the hypothesis that both fat mass (FM) and fat-free mass (FFM) are proportionately lower in children born preterm than in children born at term.

Adjusting body cell mass for size in women of differing nutritional status.

Background: Body cell mass (BCM) may be estimated in clinical practice to assess functional nutritional status, eg, in patients with anorexia nervosa. Interpretation of the data, especially in younger patients who are still growing, requires appropriate adjustment for size. Previous investigations of this general issue have addressed chemical rather than functional components of body composition and have not considered patients at the extremes of nutritional status, in whom the ability to make longitudinal comparisons is of particular importance.

Number of days needed to assess energy and nutrient intake in infants and young children between 6 months and 2 years of age.

Objective: To estimate the minimum number of days of recorded dietary intake needed to place infants and young children into thirds of a population distribution with an acceptable degree of accuracy.

Design: Dietary intake data collected from 5-day weighed food records for 72 infants and young children up to 2 y of age, collected during a cross-sectional study, were analysed to estimate the number of recording days necessary to assess intake of energy and 10 nutrients.

Setting: Community study among healthy infants and children.

Breast milk and energy intake in exclusively, predominantly, and partially breast-fed infants.

Objective: To investigate the extent to which breast milk is replaced by intake of other liquids or foods, and to estimate energy intake of infants defined as exclusively (EBF), predominantly (PBF) and partially breast-fed (PartBF).

Design: Cross-sectional.

Setting: Community-based study in urban Pelotas, Southern Brazil.

A new method for quantifying encephalization in the growing individual.

Here we describe a new method for quantifying encephalization in the growing individual and provide a worked example of the methods. The new method is based on the use of conditional SD scores derived from brain and body growth references. These encephalization SD scores control for age, sex and body size effects on brain size, and therefore, control for the confounds associated with allometry as well as growth differences between the brain and body and between the sexes.

Physical inactivity: prevalence and associated variables in Brazilian adults.

Purpose: To measure the prevalence of physical inactivity, and variables associated with it, in an adult southern Brazilian population.

Methods: Population-based cross-sectional study covering a multiple-stage sample of 3182 subjects aged 20 yr or more. Physical activity was assessed through the short version of the International Physical Activity Questionnaire (IPAQ), using home interviews with last-week recall.

Body composition in childhood: effects of normal growth and disease.

Body composition in children is of increasing interest within the contexts of childhood obesity, clinical management of patients and nutritional programming as a pathway to adult disease. Energy imbalance appears to be common in many disease states; however, body composition is not routinely measured in patients. Traditionally, clinical interest has focused on growth or nutritional status, whereas more recent studies have quantified fat mass and lean mass.

Evaluation of air-displacement plethysmography in children aged 5-7 years using a three-component model of body composition.

The aim of the present study was to evaluate air-displacement plethysmography (ADP) in children aged 5-7 years. Body-composition measurements were obtained by ADP, (2)H dilution and anthropometry in twenty-eight children. Calculation of body volume by ADP was undertaken using adult and children's equations for predicting lung volume and surface area.

Centile reference charts for total energy expenditure in infants from 1 to 12 months.

Background: A knowledge of energy expenditure in infancy is required for the estimation of recommended daily amounts of food energy, for designing artificial infant feeds, and as a reference standard for studies of energy metabolism in disease states.

Objectives: The objectives of this study were to construct centile reference charts for total energy expenditure (TEE) in infants across the first year of life.

Methods: Repeated measures of TEE using the doubly labeled water technique were made in 162 infants at 1.

Covalent attachment of gold nanoparticles to DNA templates.

Functionalized gold nanoparticles have been covalently bound to internal, modified sites on double-stranded DNA. Gold nanoparticles coated with mercaptosuccinic acid or thioctic acid were bound to amino-modified thymine bases on double-stranded DNA. Visible absorption spectra, gel electrophoresis, and atomic force microscopy were used to analyze the products.

Validity of six field and laboratory methods for measurement of body composition in boys.

Objective: To determine the validity of the following six body composition methods against a reference method (three-component model): air displacement plethysmography (BODPOD); estimation from body density using BODPOD; skinfold thickness using the Slaughter equations; bioelectrical impedance, both leg-leg (TANITA) and hand-foot (Bodystat) approaches; and total body water.

Research Methods And Procedures: Forty-two healthy white 10- to 14-year-old boys (mean age, 12.9 +/- 1.

Parent-offspring conflict theory, signaling of need, and weight gain in early life.

Human growth in early life has major implications for fitness. During this period, the mother regulates the growth of her offspring through placental nutrition and lactation. However, parent-offspring conflict theory predicts that offspring are selected to demand more resources than the mother is selected to provide.

The thrifty phenotype hypothesis: thrifty offspring or thrifty mother?

Medical research is increasingly focusing on the contribution of nutritional programming to disease in later life. Programming is a process whereby a stimulus during a critical window of time permanently affects subsequent structure, function or developmental schedule of the organism. The thrifty phenotype hypothesis is widely used to interpret such studies, with early growth restriction seen as adaptation to environmental deprivation.

Birth weight and environmental heat load: a between-population analysis.

Low birth weight, a major cause of infant morbidity and mortality, is caused by different factors in Western and developing-country populations. In addition to differing in terms of ethnicity, maternal size, maternal nutritional status, and disease load, developing-country and Western populations are also characterized by different environmental heat loads. Thermodynamic theory predicts that heat stress is mitigated by reduced size of both mother and offspring, and therefore generates the hypothesis that reduced birth weight may be an adaptation to environmental heat load.

Energy requirements and body composition in stable pediatric intensive care patients receiving ventilatory support.

Energy requirements of pediatric intensive-care patients are unknown due to the difficulty of measuring total energy expenditure in free-living conditions. We investigated energy expenditure and body composition in stable pediatric intensive-care patients receiving long-term ventilatory support. Total energy expenditure and total body water were measured in 10 such patients using the doubly-labeled water method.

The contribution of fat and fat-free tissue to body mass index in contemporary children and the reference child.

Background: Body mass index (BMI) is widely used to assess the prevalence of childhood obesity in populations, and to infer risk of subsequent obesity-related disease. However, BMI does not measure fat directly, and its relationship with body fatness is not necessarily stable over time.

Objective: To test the hypothesis that contemporary children have different fatness for a given BMI value compared to the reference child of two decades ago.

Body composition in early onset eating disorders.

Background: Body mass index (BMI) or equivalent weight for height indices are the most widely used measures of body composition in early onset and adolescent eating disorders. Although of value as screening instruments the limitation in disease states is their inability to discriminate fat and fat-free components of body weight.

Objective: To compare height-adjusted fat and fat-free components of body composition in children and young adolescents with different types of eating disorders with those of age matched reference children.

Adjustment of fat-free mass and fat mass for height in children aged 8 y.

Objective: To explore the relationships between height and (a) fat-free mass (FFM) and (b) fat mass (FM) in children in order to determine the optimum means of adjusting body composition for height.

Design: Cross-sectional study.

Subjects: Sixty-nine children aged 8 y.

Segmental bioelectrical impedance analysis in children aged 8-12 y: 2. The assessment of regional body composition and muscle mass.

Objectives: To investigate the potential of segmental bioelectrical impedance analysis (BIA) for assessing regional composition and muscle mass in children.

Design: Strengths of relationships were determined between (a) BIA indices of trunk, limbs or limb segments and (b) segment fat or fat-free mass (FFM) assessed using dual-energy X-ray absorptiometry (DXA); the extent of agreement was established between two independent models, based on DXA and BIA, of limb muscle and adipose tissue (AT) mass.

Subjects: Eighteen boys and 19 girls aged 8-12 y.