Britt Eriksson

Body composition in full-term healthy infants measured with air displacement plethysmography at 1 and 12 weeks of age.

Aim:  To use Pea Pod, a device based on air displacement plethysmography, to study body composition of healthy, full‐term infants born to well‐nourished women with a western life‐style.

Body fat, insulin resistance, energy expenditure and serum concentrations of leptin, adiponectin and resistin before, during and after pregnancy in healthy Swedish women.

Healthy human pregnancy is associated with changes in food intake, body fatness, energy expenditure and insulin resistance. However, available knowledge is limited regarding the physiological basis of these changes. Published evidence suggests that so-called adipokines (i.e. leptin, adiponectin and resistin) have significant roles when such changes are established. We explored, throughout a complete pregnancy, relationships between total body fat (TBF), energy expenditure, insulin resistance (homeostasic model of insulin resistance, HOMA-IR) and serum concentrations of leptin, adiponectin and resistin. Such concentrations were assessed before pregnancy in gestational weeks 8, 14, 20, 32 and 35, and 2 weeks postpartum in twenty-three healthy women. TBF, BMR (n 23) and HOMA-IR (n 17) were assessed before pregnancy in gestational weeks 14 and 32 and 2 weeks postpartum. TBF (%) was correlated with HOMA-IR (r 0.68-0.79, P < 0.01) and with serum leptin (r 0.85-0.88, P < 0.001) before and during pregnancy. Serum leptin was correlated with HOMA-IR (r 0.53-0.70, P < 0.05) before and during pregnancy. Serum adiponectin was inversely correlated with HOMA-IR in gestational week 32 (r - 0.52, P < 0.05). When HOMA-IR was regressed on TBF (%), the slope of the regression line was 0.046 before pregnancy, which was significantly (P < 0.05) different from the corresponding value, 0.111, in gestational week 32. The results indicate that pregnancy has an enhancing effect on the relationship between body fatness and insulin resistance. This effect, possibly mediated by leptin, may represent a mechanism by which offspring size is regulated in response to the nutritional situation of the mother.

Fat-free mass hydration in newborns: assessment and implications for body composition studies

Aim:  Equipment (Pea Pod) offering new possibilities to assess infant body composition has recently become available and has already been used in several studies. In the Pea Pod, body density is converted to body composition using one of two models (‘Fomon’ or ‘Butte’) with different water content in fat‐free mass (hydration factor, HF). In healthy full‐term infants, we assessed HF and its biological variability in 12 newborns and calculated body composition using the two models at 1 and 12 weeks in 108 infants. Body weight and volume were assessed in Pea Pod, and body water was assessed using isotope dilution.

Gestational weight gain according to Institute of Medicine recommendations in relation to infant size and body composition

Intrauterine life may be a critical period for programming childhood obesity; however, there is insufficient knowledge concerning how gestational weight gain (GWG) affects infant fat mass (FM) and fat‐free mass (FFM).

Body-composition development during early childhood and energy expenditure in response to physical activity in 1.5-y-old children

BACKGROUND The prevalence of childhood overweight and obesity has increased recently, but the mechanisms involved are incompletely known. Previous research has shown a correlation between the percentage of total body fat (TBF) and physical activity level (PAL). However, the PAL values used may involve a risk of spurious correlations because they are often based on predicted rather than measured estimates of resting energy metabolism. OBJECTIVES We studied the development of body composition during early childhood and the relation between the percentage of TBF and PAL on the basis of the measured resting energy metabolism. DESIGN Body composition was previously measured in 108 children when they were 1 and 12 wk old. When 44 of these children (21 girls and 23 boys) were 1.5 y old, their total energy expenditure and TBF were assessed by using the doubly labeled water method. Resting energy metabolism, which was assessed by using indirect calorimetry, was used to calculate PAL. RESULTS Significant correlations were shown for TBF (r = 0.32, P = 0.035) and fat-free mass (r = 0.34, P = 0.025) between values (kg) assessed at 12 wk and 1.5 y of age. For TBF (kg) a significant interaction (P = 0.035) indicated a possible sex difference. PAL at 1.5 y was negatively correlated with the percentage of TBF (r = -0.40, P = 0.0076) and the increase in the percentage of TBF between 12 wk and 1.5 y (r = -0.38, P = 0.0105). CONCLUSIONS The results indicate that body fatness and physical activity interact during early childhood and thereby influence obesity risk. Our results are based on a small sample, but nevertheless, they motivate additional studies in boys compared with girls regarding the development of body composition during early life.

Longitudinal assessment of body composition in healthy Swedish children from 1 week until 4 years of age

Background/Objectives:Knowledge of longitudinal body composition development is required to identify the mechanisms behind childhood overweight and obesity and to prevent these conditions. However, accurate data on this development in early childhood are lacking. Our aim was to describe the longitudinal body composition development in healthy young Swedish children.Subjects/Methods:Body size and composition were assessed in 26 children using air-displacement plethysmography (1 and 12 weeks and 4.4 years of age) and isotope dilution (1.5 and 3 years of age) and compared with available reference data.Results:Body fat (%) for boys (n=16) was 12.8±3.9 (1 week), 25.6±4.8 (12 weeks), 28.2±3.8 (1.5 years), 27.3±5.1 (3 years) and 26.1±3.5 (4.4 years). For girls (n=10) these values were 15.3±2.9, 25.7±3.9, 27.9±3.3, 26.3±7.2 and 26.0±5.3, respectively. These values were above the Fomon reference values at 1.5 years of age and later and higher than the Butte reference (P<0.05) for boys at 1.5 years of age. At all ages the coefficients of variation were higher for body fat (%) (12–30%) than for BMI (4-11%).Conclusions:At 4 years of age our children had more body fat than indicated by reference data. This high level may have already been established at 1.5 years of age but our small sample and the lack of appropriate reference data limit the possibility of drawing firm conclusions. Our results demonstrate the limitations of BMI when investigating overweight and obesity in early life and highlight the need for appropriate reference body composition data in infants and young children.