Standards for total body fat and fat-free mass in infants.

Data on body composition in conjunction with reference centiles are helpful in identifying the severity of growth and nutritional disorders in infancy and for evaluating the adequacy of treatment given during this important period of rapid growth. Total body fat (TBF) and fat-free mass (FFM) were estimated from total body electrical conductivity (TBEC) measurements in 423 healthy term Caucasian infants, aged 14-379 days. Cross sectional age, weight, and length related centile standards are presented for TBF and FFM. Centiles were calculated using Altman''s method, based on polynomial regression and modelling of the residual variation. The TBF percentage steeply increased during the first half year of life, and slowly declined beyond this age. Various simple TBEC derived anthropometric prediction equations for TBF and FFM are available to be used in conjunction with these standards. Regression equations for the P50 and the residual SD, depending on age, weight, or length, are provided for constructing centile charts and calculating standard deviation scores.     

Growth and body composition in preterm infants with bronchopulmonary dysplasia

OBJECTIVE: To compare growth and body composition in preterm infants with bronchopulmonary dysplasia (BPD) with normal healthy term infants during the first year of life. DESIGN: Twenty nine preterm infants with BPD (mean (SD) gestational age 27.1 (1.6) weeks; birth weight 852 (173) g) were followed prospectively. Anthropometry and body composition determined by total body electrical conductivity were measured and compared with those of healthy term infants at the same post-term age. RESULTS: In infants with BPD, the mean weight standard deviation scores (SD scores) 6 weeks after term were significantly lower (-1.44 and -2.68, boys and girls respectively) than in healthy term infants of the same age and did not improve during the first year. The mean length SD score was significantly lower in infants with BPD 6 weeks after term than in healthy term infants of the same age, and, although it improved significantly during the first year, the mean length SD score in girls with BPD was significantly below 0 12 months after term. In infants with BPD, the mean free fat mass (FFM) SD score and the mean total body fat (TBF) SD score at 6 weeks post-term age were significantly below 0. The mean FFM SD scores (-1.01 and -2.56, boys and girls respectively) and the mean TBF SD scores (-1.14 and -2.40, boys and girls respectively) 12 months after term were significantly lower than in healthy term infants of the same age. CONCLUSIONS: Preterm infants with BPD have impaired growth, with a deficit in TBF and FFM already 6 weeks after term; FFM and TBF remain low compared with healthy term infants during the first year of life. Nutritional intervention studies in infants with BPD are needed to evaluate if nutrition is the major determinant of growth and body composition or if this pattern of growth in preterm infants with BPD is the result of disturbed endocrine control.     

Spontaneous growth in German children and adolescents with genetically confirmed Prader-Willi syndrome

Height and weight in children with Prader-Willi syndrome, diagnosed by standard clinical criteria, follow a specific developmental pattern resulting in early childhood obesity, absent pubertal growth spurt and adolescent short stature. New molecular techniques (methylation analysis, fluorescence in situ hybridization) now allow the unequivocal diagnosis of Prader-Willi syndrome (PWS). We investigated the possibility of a bias in syndrome-specific growth standards based on clinically diagnosed patients by comparing these standards with new standards derived from 100 German patients with molecularly confirmed PWS, none of whom had received a growth-promoting therapy. Height centile curves of the German patients fall in the tall range of standards derived from American patients. This is mainly due to an elevation of the lower centile ranges in both sexes. When the height standards derived from German patients are compared to those of a large multinational cohort of patients, 78% of whom were not confirmed by genetic testing, only minor differences in the height centiles become apparent. The population background therefore does not appear to play a major role for the observed differences. In a marked proportion of patients a decreased sitting height/height ratio is found. This was usually associated with scoliosis. Weight standards from our study group show that after 14 y of age German girls with PWS are heavier than their American counterparts. Standards for the body mass index of German patients of both sexes are increased over normal reference standards (p < 0.0001) and do increase with age (boys: p = 0.0038; girls: p = 0.0004). PWS genotypes or sex had no apparent influence on SDS for height, weight and body mass index. Conclusions: Because of the observed differences to other growth standards, use of the newly constructed centile curves is advocated in German patients with molecularly confirmed PWS to avoid delay in the diagnosis of additional growth-compromising conditions.     

Determination of body composition in growing rats by total body electrical conductivity.

Total body electrical conductivity (TOBEC), measured with an Em-Scan SA-1 analyzer, was evaluated as a means of estimating fat-free mass and total body water content noninvasively in small laboratory animals. Ninety-four rats whose weight ranged from 5.53 to 170.84 g at 0-50 days of age were studied. The animals were killed by intraperitoneal injection of a pentobarbital overdose. After weight, crown-rump length (CRL) and TOBEC were measured, and the animals were minced with scissors and desiccated to constant weight in a convection oven. Fat was extracted by multiple bathings in petroleum ether followed by Soxhlet extraction. Fifty-four rats were used to determine the relation between fat-free mass (FFM), total body water (TBW), and TOBEC# (E) by regression analysis. The best correlations were observed between FFM and (E x CRL)1/2 (r = 0.995, p less than 0.0001). Forty rats were used to determine the predictive value of TOBEC estimates. With this instrument, TOBEC tended to underestimate FFM by an average of 3.9% and TBW by 5.3%. Accuracy was questionable for animals smaller than 13 g and TOBEC did not provide useful estimates of total body fat. Subject to these limitations, TOBEC instruments should prove to be useful for sequential in vivo estimations of body composition during growth and development of small animals.     

Comparison of the use of Tanner and Whitehouse, NCHS, and Cambridge standards in infancy

The British (Tanner and Whitehouse) and American (National Center for Health Statistics, NCHS) growth standards are widely used internationally, although the data are now over 30 years old. Routine weight data was retrieved from the child health records of a complete annual cohort of 3418 children aged 18-30 months to test the validity of these standards for modern infants. Compared with the Tanner and Whitehouse standards, Newcastle children rose initially and then fell a mean of 0.7 SDs between 6 weeks and 18 months, resulting in a threefold difference in the proportion of children below the 3rd centile at different ages. NCHS standards showed a similar pattern. When compared with modern standards from the Cambridge growth study, there was a much closer match, although Newcastle children showed a slight gain by the age of 1 year. Existing standards for weight introduce inaccuracy into the estimation of centile position in the early months of life. As both standards show similar problems this probably represents a real secular change due to changes in infant nutrition. These findings support the need to develop new national growth reference standards.     

Comparison of the use of Tanner and Whitehouse, NCHS, and Cambridge standards in infancy.

The British (Tanner and Whitehouse) and American (National Center for Health Statistics, NCHS) growth standards are widely used internationally, although the data are now over 30 years old. Routine weight data was retrieved from the child health records of a complete annual cohort of 3418 children aged 18-30 months to test the validity of these standards for modern infants. Compared with the Tanner and Whitehouse standards, Newcastle children rose initially and then fell a mean of 0.7 SDs between 6 weeks and 18 months, resulting in a threefold difference in the proportion of children below the 3rd centile at different ages. NCHS standards showed a similar pattern. When compared with modern standards from the Cambridge growth study, there was a much closer match, although Newcastle children showed a slight gain by the age of 1 year. Existing standards for weight introduce inaccuracy into the estimation of centile position in the early months of life. As both standards show similar problems this probably represents a real secular change due to changes in infant nutrition. These findings support the need to develop new national growth reference standards.     

Body composition during the first 2 years of life: an updated reference

Normative body composition during the first 2 y of life was derived from a prospective study of 76 children. We present 1) fat free mass (FFM) and its components, and fat mass (FM), 2) incremental growth rates partitioned into chemical components, and 3) age-specific and gender-specific constants for converting chemical and physical components into FFM for children during the first 2 y of life. A multicomponent model based on measurements of total body water (TBW), total body potassium (TBK) and bone mineral content (BMC) was used to estimate FFM and FM at 0.5, 3, 6, 9, 12, 18, and 24 mo of age. TBW was determined by deuterium dilution, TBK by whole body counting, and BMC by dual energy x-ray absorptiometry. FFM was higher in boys than girls between 0.5-18 mo of age (p < or = 0.05). Percent FM increased on average from 13 to 31% between 0.5 and 3-6 mo, and then gradually declined. Percent FM was significantly higher in girls than in boys at 6 and 9 mo of age (p < or = 0.02). The components of FFM on a percentage basis changed with age (p = 0.001), but not gender. The protein content of FFM increased gradually with age, while TBW declined (p = 0.001). As a percentage of FFM, osseous mineral increased from 2.0 to 3.4% in boys and from 2.1 to 3.3% in girls between 0.5 and 24 mo (p = 0.001). Density and potassium content of FFM increased gradually with age (p = 0.001). These normative body composition data provide an updated reference upon which to assess normal growth and nutritional status of pediatric populations representative of mixed feeding groups during the first 2 y of life.     

DEVELOPMENT OF PULMONARY FUNCTION IN LATE GESTATION: I. The Functional Residual Capacity of the Lung in Premature Children

Functional residual capacity has been measured in premature and term infants soon after birth and repeatedly thereafter. Good correlation with body weight, length and gestational age have been found. However, the known relationships between the development of lung volume and attributes of body growth in older individuals are only partially valid during late gestation. Some peculiar growth patterns observed in this age could be explained by disproportionate variations in the rate of growth of body length and weight on the one hand and of lung volume on the other. By extrapolation over a very short range it was possible to verify the post mortem estimates of the gestational age at which alveolization occurs.     

Catch up Growth in Preterm Infants

Seventy-one surviving infants were followed up from birth to 24 weeks of postnatal age. Their mean gestational age was 32 weeks with a range of 26–36 weeks and a standard deviation of 2.1 weeks. Their mean birth weight was 1.805 kg with a range of 0.675–2.5 kg and a standard deviation of 0.408 kg. Their weights, lengths and head circumferences were measured at birth, 6, 12 and 24 weeks. Curves for the mean weight, length and head circumference were produced and superimposed on the available intrauterine and extra-uterine growth charts. The growth curves of the preterm infants did not show the flattening noted in the intrauterine curves towards term. The curve of the mean weight of the preterm infants started at the 50th centile for Gairdner & Pearson (1971) at birth to drop below that shortly after birth. At 40 weeks of postconceptional age the mean weight curve of preterm infants crossed the 50th centile and continued above it to reach the 90th centile at 60 weeks. The curves of mean length and head circumference started below the 50th centile at birth and crossed it at 40 weeks and continued above it to approach the 90th centile at 60 weeks. Growth velocity was calculated as a relative gradient using the straight line equation (y=a+bx), where y is the weight, length or head circumference, and x is the independent variable and here it is the group mean of the parameter at the corresponding ages. Catch up growth is taken as a relative gradient significantly greater than one. The first 24 weeks of postnatal life are defined as a period of catch up growth with the first 8 weeks as an interval of maximum head velocity.     

Studies on human body composition during the first 4 months of life using magnetic resonance imaging and isotope dilution

Assessing body composition during infancy requires data for the so-called reference infant. Currently available data for this purpose need to be updated and extended using methods based on principles different from those used previously to define the reference infant. Thus, magnetic resonance imaging was applied to full-term healthy boys (n = 25) and girls (n = 21), 4-131 d old, to estimate adipose tissue volume (ATV) and the amounts of s.c. and non-s.c. adipose tissue (AT). Total body water was estimated using isotope dilution. Total body fat (TBF), fat free weight (FFW) and the degree of hydration in FFW were calculated. Increases in weight, TBF, and FFW with age agreed with current reference data, although when compared with the reference, a slightly more rapid increase in % TBF was observed for boys. The degree of hydration in FFW was 78.9 +/- 4.5% (n = 45). Both sexes showed significant increases with age in s.c. ATV (14.7 and 13.0 mL/d for boys and girls, respectively) and in non-s.c. ATV (1.58 and 1.26 mL/d, respectively). Subcutaneous ATV was 90.5 +/- 1.8% (boys) and 91.1 +/- 1.9% (girls) of total ATV. In conclusion, a pronounced increase with age in the amount of AT was demonstrated involving a considerable gain in s.c. fat during early life. Except for % TBF in boys, changes in body composition with age agreed with current reference data.     

Growth charts for use in Australia

Growth charts for use in Australia have recently been modified. Changes have been made to both height for age and weight for age charts as well as body mass index for age. The charts are now based on the published CDC 2000 growth data which are more contemporary than the data used to construct the previous charts. A first centile for height for age has been included as this is used as a screening tool for the provision of growth hormone to children in Australia. The calculation of a precise first centile has been possible as the CDC data includes LMS values which have other significant advantages in the creation of the growth charts. It is noteworthy that the most recently collected anthropometric data for weight (and hence body mass index) have not been included in the calculation of these two charts as it was believed that increasing numbers of children who are overweight or obese in the population would skew these charts in an undesirable way. Height velocity for age and other charts remain unchanged.     

Body measurements, neurological and behavioural development in six-year-old children born preterm and/or small-for-gestational-age

In three groups of low birth weight (LBW) infants: full term, small-for-gestational-age (FT-SGA, N = 142); preterm, appropriate-for-gestational-age (PT-AGA, N = 47); preterm, small-for-gestational-age (PT-SGA, N = 20); and a reference group of FT-AGA infants (N = 185) the relationship between body weight, body length and head circumference and the presence of minor neurological dysfunction (MND) was studied. Non-caucasian and handicapped children were excluded from the analysis. Data were collected on behaviour and school achievement. The parameters of physical growth in the three LBW groups were reduced significantly compared to the FT-AGA group. In both preterms and full-terms body measurements were related to weight at term age; in the preterm groups no relation with gestational age at birth was found. MND was not related to body weight or length. In the group of FT severely growth retarded infants a relation was found between a skull circumference below the third centile and the presence of MND. Body measurements, behaviour at home and at school and school achievement were not related. The significance of severe intrauterine growth retardation for developmental disorders is emphasized. The data suggest a different aetiology and clinical significance of small head size for AGA and SGA born children.     

Physical and sexual growth pattern of affluent Indian children from 5 to 18 years of age.

The present study was conducted to study growth parameters on 12,899 boys and 9,951 girls of affluent class from 8 States of the country. In pooled data, the 50th centile height approached 30-40th centile till 6 1/2 years in boys and up to 10 years in girls, and ultimately the height growth curves for both fell between the 10-20th centile of NCHS standards. Similarly, for weight, they approached 10-20th centile of NCHS at the age of 17 yr. Comparison with other European countries showed that Indian affluents are shorter and lighter; however, they are similar to their counterparts of Asian origin. The secular trend for height in Delhi showed increase of 2.1 cm for boys, and 2.7 cm for girls per decade at 17 yr and 14 yr, respectively. In Varanasi, the corresponding trend was 1.5 and 2.1 cm at 16 yr for boys and girls, respectively. The mean ages for genital development stages G 2-5 were 11.9, 13.3, 14.6 and 15.9 yr; respectively. In girls, the breast development Stages B 2-5 had mean ages of 10.9, 12.8, 13.9 and 14.8 yr, respectively. The mean age for menarche was 12.6 yr. In 14 yr old boys, the mean height may vary between 150.3, 155.8, 161.2 and 165.2 cm and mean weight between 38.0, 42.5, 46.8 and 52.9 kg for genital stages G 2-5, respectively. Similarly, girls of 12.5 yr (close to menarcheal age of 12.6 yr) had mean height 145.3, 150.3, 152.1 and 153.8 cm and mean weight 34.7, 41.2, 45.4 and 54.4 kg for breast stages B 2-5, respectively. It is recommended that for growth assessment during adolescence these charts in relation to sexual development and age be used for comparison.     

Birthweight and subsequent growth of children exposed to rubella infection in utero

Birthweight, and head circumference and body weight at preschool age were studied in a group of 212 children exposed to maternal rubella infection. Birthweights were compared to standards for birthweights of British children according to gestational age and birth rank. Children with detectable rubella antibody at the time of the examination were regarded as seropositive and those with no detectable antibody as seronegative. It was shown that the mean birthweight of seronegative and seropositive children without rubella defects did not differ significantly from the 50th centile or from each other, but that those who were seropositive with defects had significantly lower birthweights. Head circumference and body weight were similarly compared to current British standards. Head circumference at follow-up was normal in seronegative and seropositive children without defects, but significantly low in seropositive children with defects, even if retinopathy was the sole defect. The findings for body weight at follow-up were similar, reflecting absence of catch-up growth in weight in the children with congenital rubella defects.This study has shown that intrauterine growth retardation does not present as the sole manifestation of maldevelopment in congenital rubella.     

Growth patterns of Chinese patients with Prader‐Willi syndrome

The aim of the present study was to investigate the spontaneous development of growth and weight gain of patients with Prader‐Willi syndrome (PWS) in Mainland China. We retrospectively analyzed 120 cases of PWS diagnosed from 1994 to 2014 in Mainland China. Scatter diagram of the growth data was compared to standardized growth curve. The length at birth was similar to the normal population and the mean birthweight is under the 50th centile of normal population. Heights in 43% (27/62) of patients had dropped off below the 3^rd centile of their peers after 5 years of age. Weights in 65.9% (58/88) of patients had exceeded the 97^th centile of their peers after 3 years of age. Early obesity is obvious in 92.9% (66/71) of patients with body mass index (BMI) up the 97^th centile of their peers from 2–3 years of age. Final mean height is 149.3 ± 11.2 cm for females (n = 7) and 146.2 ± 9.8 cm for males (n = 6), showing 11.3 cm and 26.6 cm below the average height for normal Chinese girls and boys. The growth pattern of PWS in Mainland China is comparable to those in Caucasians. Early intervention with recombinant human growth hormone is warranted considering the early onset of growth retardation and obesity.     

Growth and very low birth weight.

Information on the likelihood of catch up growth in poorly grown very low birthweight children is sparse. The centiles for weight, height, and head circumference were recorded at both 2 and 5 years of age for 135 very low birthweight children and 42 normal birthweight children. At both ages significantly more children of very low birth weight were under the 10th centile for weight and height. Children of birth weight under 1000 g were more often under the 10th centile for weight at 5 years compared with those of birth weight 1000-1500 g. Mean incremental weight gain between 2 and 5 years was significantly less for very low birthweight children. Mean increment in weight from 2 to 5 years was less for very low birthweight children who had been under the 10th centile for weight at 2 years; children who had been under the 10th centile for height also had lower mean height increments. The growth centiles achieved by 2 years of age were useful predictors of poor growth at 5 years, with perinatal data of marginal importance. Only six of 43 (14%) children with a weight at 5 years of age under the 10th centile were small for gestational age at birth. Very low birthweight children who had a weight or height under the 10th centile at 2 years of age usually remained in this category at 5 years with no evidence of catch up growth.     

Gain in weight and length during early infancy

Although rate of growth is generally recognized as a valuable indicator of health status, few reference data are available for gain in weight or length during the period of most growth in infancy. We have therefore summarized our data concerning gains in length and weight of 203 breast-fed males, 216 breast-fed females, 380 formula-fed males, and 340 formula-fed females. Seven sets of measurements (at ages 8, 14, 28, 42, 56, 84 and 112 days) were made with each infant. The 5th, 10th, 25th, 50th, 75th, 90th and 95th centile values together with the means and standard deviations are presented for selected age intervals on a feeding-specific (i.e. breast-fed or formula-fed) and sex-specific basis. We believe that these data will be useful as a reference for interpreting results of infant studies.     

中国七岁以下儿童身长/身高的体重和体块指数的生长标准值及标准化生长曲线

目的 制定中国7岁以下儿童身长/身高的体重、体块指数(BMI)的生长标准值及标准化生长曲线.方法 选择"2005年九市儿童体格发育调查"中69 622名城区7岁以下儿童的身长/身高、体重测量值,采用LMS法分别建立身长的体重和BMI模型.将3岁后身高加上0.7 cm与身长对接,构建统一身长的体重LMS模型,数据拟合后可将身长减去0.7 cm转化为身高的体蕈.BMI采取"身长BMI"和"身高BMI"分别独立拟合的方法,将身高加上0.7 cm计算"身长BMI",在整个年龄段拟合"身长BMI"LMS模型,类似地可建立"身高BMI"模型.曲线的拟合效果评价采用拟合优度X2检验.结果 制定出中国儿童45～105 cm身长的体重、65～125 cm身高的体重、0～3岁年龄的BMI(由身长计算)、2～7岁年龄的BMI(由身高计算)的按百分位数及标准差单位的生长标准值及标准化生长曲线图.该参照标准总体上略高于世界卫生组织新标准,而略低于美国疾控中心2000年修订标准(CDC2000).结论 本研究制定的身长/身高的体重及BMI标准具有国家代表性,可在全国范围内用于儿童生长监测与营养评估.     

Adequacy of standards for assessment of growth and nutritional status in infancy and early childhood.

BACKGROUND: New "UK 1990" data have been proposed for assessing growth and nutritional status in infancy and childhood. These are still largely untried in clinical practice. There is also doubt about the applicability of more traditional reference data, which are still widely used, in assessing length, weight, skinfold thicknesses, and head circumference. AIMS: To determine the suitability of new and traditional reference data for the assessment of growth and nutritional status in infancy and early childhood. METHODS: 127 infants were recruited at birth and assessed monthly to 6 months of age then at 9, 12, 18, and 24 months. Length, weight, head circumference, and triceps and subscapular skinfold thicknesses were measured. Body mass index (BMI) was calculated. Measurements were expressed as standard deviation scores relative to "revised UK 1990" data for weight, length, head circumference and BMI; relative to Tanner-Whitehouse data for skinfold thicknesses; and relative to Gairdner-Pearson standards for head circumference. Agreement at the extremes of the distribution was assessed by comparison of observed and expected frequencies above the 90th and below the 10th centile. RESULTS: Compared with the revised UK 1990 references small differences were found for weight, length, head circumference, and BMI. Mean head circumference exceeded Gairdner-Pearson standards at all ages. Triceps and subscapular skinfold thicknesses were substantially below Tanner-Whitehouse reference data at all ages and in both sexes. CONCLUSION: Biases in revised UK 1990 reference data are small and not clinically important. The new standards are considerably more appropriate than older reference data. Use of older reference data for head circumference and skinfold thicknesses is inappropriate.     

Plasma somatomedin activity in an infant with Beckwith—Wiedemann syndrome

Plasma growth hormone levels and somatomedin activity were determined in a child with Beckwith-Wiedemann syndrome at birth and at 8 mth of age. Birthweight and length were above the 97th centile. Somatomedin activity in the cord plasma was elevated (2.8 U/ml) compared with controls (0.15-1.3 U/ml; n=15). Growth hormone was also high (76 ng/ml compared with control group range of 5.5–42.1 ng/ml, n=26). At 8 mth of age both somatomedin activity and plasma growth hormone had fallen to normal levels and weight and length were on the 75th centile. It is suggested that the high somatomedin activity may have been a contributing factor in the excessive fetal growth of this child.