Infant body composition at 6 and 24 months: what are the driving factors?

BACKGROUND/OBJECTIVE: Available evidence on infant body composition is limited. This study aimed to investigate factors associated with body composition at 6 and 24 months. SUBJECTS/METHODS: Multicenter study with data from a 0 to 6-mo cohort (Australia, India and South Africa) and a 3 to 24-mo cohort (Brazil, Pakistan, South Africa, and Sri Lanka). For the 0-6-mo cohort, body composition was assessed by air-displacement plethysmography (ADP) and for the 3-24-month cohort by the deuterium dilution (DD) technique. Fat mass (FM), fat-free mass (FFM), FM index (FMI), and FFM index (FFMI) were calculated. Independent variables comprised the Gini index of the country, maternal and infant characteristics, and breastfeeding pattern at 3 months. For the 3-24-mo cohort, breastfeeding, and minimum dietary diversity (MDD) at 12 months were also included. Crude and adjusted analyses stratified by sex were conducted by multilevel modelling using mixed models. RESULTS: At 6 months, every 1 kg increase in birth weight was associated with an increase of 0.716 kg in FFM and 0.582 kg/m2 in FFMI in girls, whereas in boys, the increase was of 0.277 kg in FFM. At 24 months, compared to those weaned before 12 months, girls still breastfed at 12 months presented a decrease of 0.225 kg in FM, 0.645 kg in FFM and 0.459 kg/m2 in FFMI, and in boys the decreases were of 0.467 kg in FM, 0.603 kg in FFM and 0.628 kg/m2 in FFMI. CONCLUSION: Birth weight and breastfeeding are independent predictors of body composition in early life, irrespective of sex.

Anthropometry and physical activity level in the prediction of metabolic syndrome in children.

OBJECTIVE: To evaluate the effectiveness of anthropometric measures and physical activity level in the prediction of metabolic syndrome (MetS) in children. DESIGN: Cross-sectional study with children from public and private schools. Children underwent an anthropometric assessment, blood pressure measurement and biochemical evaluation of serum for determination of TAG, HDL-cholesterol and glucose. Physical activity level was calculated and number of steps per day obtained using a pedometer for seven consecutive days. SETTING: Viçosa, south-eastern Brazil. SUBJECTS: Boys and girls (n 187), mean age 9·90 (SD 0·7) years. RESULTS: Conicity index, sum of four skinfolds, physical activity level and number of steps per day were accurate in predicting MetS in boys. Anthropometric indicators were accurate in predicting MetS for girls, specifically BMI, waist circumference measured at the narrowest point and at the level of the umbilicus, four skinfold thickness measures evaluated separately, the sum of subscapular and triceps skinfold thickness, the sum of four skinfolds and body fat percentage. CONCLUSIONS: The sum of four skinfolds was the most accurate method in predicting MetS in both genders.

Within- and between-day repeatability and variability in children's physiological responses during submaximal treadmill exercise.

The purpose of this study was to verify within- and between-day repeatability and variability in children's oxygen uptake (VO2), gross economy (GE; VO2 divided by speed) and heart rate (HR) during treadmill walking based on self-selected speed (SS). Fourteen children (10.1 +/- 1.4 years) undertook three testing sessions over 2 days in which four walking speeds, including SS were tested. Within- and between-day repeatability were assessed using the Bland and Altman method, and coefficients of variability (CV) were determined for each child across exercise bouts and averaged to obtain a mean group CV value for VO2, GE, and HR per speed. Repeated measures analysis of variance showed no statistically significant differences in within- or between-day CV for VO2, GE, or HR at any speed. Repeatability within- and between-day for VO2, GE, and HR for all speeds was verified. These results suggest that submaximal VO2 during treadmill walking is stable and reproducible at a range of speeds based on children's SS.

Combined effect of body position, apparatus and distraction on children's resting metabolic rate.

OBJECTIVE: To verify the combined effect of body position, apparatus and distraction on children's resting metabolic rate (RMR). METHODS: Experiments were carried out on 14 children aged 8-12 (mean age = 10.1 years +/- 1.4). Each participant underwent two test sessions, one week apart under three different situations: a) using mouthpiece and nose-clip (MN) or facemask (FM); b) sitting (SEAT) or lying (LY); and c) TV viewing (TV) or no TV viewing. In the first session, following 20 min rest and watching TV, the protocol was: LY: 20 min stabilization; 10 min using MN and 10 min using FM. Body position was then changed to seated: 20 min stabilization; 10 min using FM; 10 min using MN. In the second session, FM and MN order was changed and participants did not watch TV. Data were analysed according to the eight combinations among the three studied parameters. RESULTS: Repeated measures ANOVA indicated statistically significant differences for VO2 (p =0.01) and RMR (p =0.02), with TVMNSEAT showing higher values than TVFMLY. Bland-Altman analysis showed a bias for VO2, VCO2, respiratory quotient (RQ) and RMR between TVFMLY and TVMNSEAT, respectively, of -17.8+/-14.5 (ml min), -8.8+/-14.5 (ml min), 0.03+/-0.05 and -115.2+/-101.9 (kcal/day). CONCLUSION: There were no differences in RMR measurements due to body position and apparatus when each variable was isolated. Analyses of distraction in three of four combinations indicated no difference between TV and no TV. Different parameter combinations can result in increased bias and variability, and thereby the reported differences among children's RMR measurement.

Physical activity and nutritional status of children of low socioeconomic status. Two interrelated problems: undernutrition and overweight.

The aim of this study was to analyse the level of habitual physical activity (HPA) and nutritional status of children attending selected public schools in Brazil. The sample comprised 1719 participants who ranged in age from 11 to 14 yrs with 861 females (F) aged 12.7+/-1.0 yr and 858 males (M) aged 12.7+/-1.0 yr. The short form of the International Physical Activity Questionnaire (IPAQ) was used to measure HPA. Nutritional status was assessed using the body mass index (BMI). Statistical analyses included ANOVA followed by the post-hoc Tukey-test (P<0.05) which showed a statistically significant difference between M and F in time spent in moderate intensity physical activity. F completed more moderate intensity physical activity than M whereas time in vigorous physical activities was higher in M than F. Analyses of BMI and IPAQ categorical score using Pearson product moment correlations with subsequent Fisher Z transformation showed values of Z = 0.49 for females and Z = 0.44 for males, indicating a low relationship between these variables. HPA levels showed 93.7% of the M and 91.1% of the F were at least minimally active. According to BMI values, 7.3% of the cohort was underweight; 83.0% normal weight; 8.3% overweight and 1.3% obese. These results demand attention, particularly for children at the lower end of nutritional status and HPA levels due to the potential negative impact on their growth and development. At the other end of the nutritional spectrum, one needs to be concerned regarding the levels of excess body weight, mainly considering the poor region in which the children live.