Body composition in neonates: relationship between measured and derived anthropometry with dual-energy X-ray absorptiometry measurements

This study examined the relationship between measured and derived anthropometric measurements with dual-energy X-ray absorptiometry measured lean and fat mass at 3.0 +/- 2.8 (SD) days in 120 neonates with birth weights appropriate (AGA; n=74), large (LGA; n=30); or small (SGA, n=16) for gestational age. Anthropometric measurements, including total body weight and length, and regional measurements, including circumferences of head, chest, abdomen, midarm, and midthigh and dynamic skinfold thickness (15 and 60 s) at tricep, subscapular, suprailiac, and midthigh, were performed. Derived anthropometry included muscle and fat areas, and ratios were calculated from direct measurements. The skinfold thickness measurements between 15 and 60 s were highly correlated (r=0.973-0.996, p <0.001 for all comparisons). Strong correlations existed within the four circumferences of trunk and extremities, the four skinfolds, and the ratios of weight to length and its higher powers. Weight and length accounted for >97% of the variance of lean mass in AGA and SGA infants and 46% of the variance in LGA infants and for 80, 82, and 84% of the variance of fat mass in SGA, AGA, and LGA infants, respectively, whereas midarm:head circumference ratio and arm muscle and fat areas are the most important derived anthropometry in the prediction for body composition. They independently accounted for up to 16.5 and 10.2%, respectively, of the variance in body composition depending on the state of in utero growth. Thus, total body weight and length and some selected regional and derived anthropometry accounted for the vast majority of the variance of body composition.     

Bone, lean and fat mass of newborn twins versus singletons

AIM: Twin gestations are associated with disturbed fetal growth. The aim of this study was to compare body composition measurements of twins to those of singletons. METHODS: Anthropometric and dual energy X-ray absorptiometry (DXA) measurements were performed in twins and in matched singleton neonates. There were 48 pairs of twins in which 76 infants were appropriate for gestational age (AGA) with birth weights between the 10th and 90th percentile and 20 were small for gestational age (SGA) with birth weights <10th percentiles. Each AGA twin was matched as closely as possible for birth weight to an AGA singleton. Each SGA twin was matched with two cohorts of AGA singletons: one with similar birth weight and one with similar gestation. RESULTS: For AGA twins and their singleton cohort matched for birth weights, profile analysis using repeated measure analysis of variance showed that there were no significant differences in bone, fat and lean mass either as absolute values or as percentage of total weight. This was also the case for body composition of SGA twins compared to singletons matched for birth weight. In contrast, SGA twins have significantly lower absolute amounts of lean with tendency to lower fat and bone mass. CONCLUSION: For clinically normally grown neonates, with comparable weight, the body composition with respect to bone, fat and lean mass components are similar regardless whether they are products of singleton or twin pregnancies.     

Birth weight categorization according to gestational age does not reflect percentage body fat in term and preterm newborns

This study was performed to prove the applicability of the small-for-gestational age (SGA), appropriate-for-gestational age (AGA), and large-for-gestational age (LGA) classification depending on birth weight to predict percentage body fat (%BF) measured by dual-energy X-ray absorptiometry (DXA) in term and preterm infants. The data of 159 healthy term and preterm neonates (87 boys and 72 girls) with a gestational age at delivery of 38.4 weeks from two longitudinal studies were analyzed. Anthropometry and body composition data were assessed within the first 10 days after birth. Correlations between anthropometric parameters and fat mass measured by DXA were calculated. Prevalences of observations with low, middle, and high %BF measured by DXA were compared between SGA, AGA, and LGA groups, according to sex and gestational age. In term infants, 42.9% of the newborns with less than 10% body fat were classified to be AGA; 9.9% of all AGA newborns had less than 10% body fat. For the whole group, among the ratios investigated, the weight-length ratio (r=0.82) showed the best correlation to fat mass measured by DXA. The %BF at the time of study was higher in girls (14.75%) than in boys (11.95%). In conclusion, traditional classification based on birth weight centiles does not reflect %BF in term and preterm newborns.     

Mid-arm circumference/head circumference ratios for identification of symptomatic LGA, AGA, and SGA newborn infants

Mid-arm circumference/head circumference ratios (MAC/HC) and birth weights obtained in 73 neonates were studied to compare which of these growth measurements could more accurately predict risk of metabolic complications resulting from either acceleration or retardation of fetal growth. The MAC/HC ratio was more sensitive than birth weight in distinguishing symptomatic large for gestational age (LGA) infants who were born to diabetic mothers from other LGA infants who were asymptomatic, and symptomatic from asymptomatic small for gestational age infants. In addition, the MAC/HC ratio identified symptomatic appropriate for gestational age (AGA) infants born to diabetic mothers and AGA infants with signs and symptoms of growth retardation. The MAC/HC is more useful than birth weight in assessing newborn infants at risk for the metabolic complications associated with fetal growth disorders.     

大于胎龄儿脐血脂联素水平测定及其临床意义

目的探讨大于胎龄儿(LGA)血脂联素水平变化及其对新生儿的影响。方法研究对象为LGA和适于胎龄儿(AGA)各30例。应用酶联免疫吸附法(ELISA)测定脐血和产妇血脂联素水平,用免疫比浊法测定三酰甘油(TG)、总胆固醇(TCH)、低密度脂蛋白胆固醇(LDL-c)、高密度脂蛋白胆固醇(HDL-c)水平,并分析脐血脂联素水平与母血脂联素、新生儿性别、出生体质量、体质量指数(BMI)、胎盘重量和血脂水平的相关性。结果1.LGA脐血浆脂联素水平低于AGA,差异有非常显著性(P<0.01);LGA血TG、TCH、LDL-c、HDL-c水平与AGA比较差异均无显著性(Pa>0.05)。2.LGA血浆脂联素水平与新生儿出生体质量、BMI、胎盘重量、脐血TG水平均呈显著负相关(r=-0.848,-0.785,-0.835 Pa<0.001),与母血脂联素水平、新生儿身长、孕前和分娩时产妇体质量及其BMI、其他脐血脂成分无相关性(Pa>0.05)。3.LGA男婴和女婴脐血浆脂联素、血脂各成分水平比较差异均无显著性(Pa>0.05)。结论血脂联素水平变化与LGA的发生有关,测定脐血脂联素水平有助于判断LGA的发展趋势。     

Vascular retinal abnormalities in neonates of mothers who smoked during pregnancy

OBJECTIVE: To investigate whether maternal smoking during pregnancy causes retinal abnormalities in the newborn. STUDY DESIGN: One hundred sixty-two neonates of smoking mothers and 162 matched neonates of nonsmoking mothers (112 appropriate for gestational age [AGA], 30 small for gestational age [SGA], 20 large for gestational age [LGA] in each group) were studied. RESULTS: Retinal arterial narrowing and straightening (RANS) was observed in 52 and 10 eyes of the newborns of smoking and nonsmoking mothers, respectively (P <. 000001) in association with elevated blood pressure in the neonates. The frequency of RANS was more than 3-fold greater in the SGA neonates than in the AGA and LGA neonates of the smoking mothers. Retinal venous dilatation and tortuosity (RVDT) was found in 100 and 36 eyes of neonates of smoking and nonsmoking mothers, respectively (P <.000001). The frequency of RVDT in the SGA neonates of the smoking mothers was 2.5-fold and 4.2-fold greater than in the AGA infants and the LGA infants, respectively. Also, intraretinal hemorrhages were found in 61 and 31 eyes of neonates of smoking and nonsmoking mothers, respectively (P =.0007) in association with elevated hematocrit and RVDT, whereas no intraretinal hemorrhages were found when RANS was present. All retinal abnormalities resolved by 6 months in infants of smoking mothers and by 2 months in infants of nonsmoking mothers. CONCLUSIONS: Maternal smoking during pregnancy causes increased frequency of RANS, RVDT, and intraretinal hemorrhages; but these retinal abnormalities resolve by 6 months of age.     

Anthropometric assessment of nutritional status in newborn infants. Discriminative value of mid arm circumference and of skinfold thickness

74 appropriate-for-gestational age (AGA) and 22 small-for-gestational age (SGA) caucasian infants were studied for anthropometric parameters: mid arm circumference (MAC), triceps and subscapular skinfold thickness (TSKF and SSKF) recorded at 15 and 60 s, chest circumference (cc), head circumference, birth weight and length.MAC is highly correlated with birth weight either in AGA (r = 0.936; P < 0.001) or in SGA infants (r = 0.860; P < 0.001). MAC is also correlated with gestational age in AGA (r = 0.850; P < 0.001) and SGA infants (r = 0.76; P < 0.001). Similar correlations were found between TSKF, SSKF and birth weight or gestational age. Arm muscle and fat areas are also positively correlated with birth weight and gestational age, in AGA and SGA infants.A multiple regression analysis of our data allowed a classification of the best discriminant anthropometric parameters between AGA and SGA infants. MAC, SSKF15, SSKF60 and chest circumference were selected. An equation was established in AGA infants with these four parameters giving a predictive gestational age: gestational age (weeks) = 1.216 MAC (cm)?3.588 SSKF15 (mm)+0.263 CC (cm) + 17.9.The ratio of predicted gestational age to the real gestational age was 1.0 ± 0.044 in AGA versus 0.896 ± 0.034 in SGA infants.Our data suggest that MAC and SSKF provide a simple measure of body composition of neonates and a useful tool for determining the degree of maturity of a newborn independent of birth weight.     

Body size and early growth in appropriate- and large-for-gestational-age infants

AIMS: To study weight, length, body composition, sleeping energy expenditure (SEE), and respiratory quotient (RQ) at birth and at 5 mo of age in both adequate-for-gestational-age (AGA) and large-for-gestational-age (LGA) subjects; to compare the changes in body weight and body composition adjusting for gender, age, SEE, RQ and several maternal factors; to investigate the contribution of initial SEE and RQ to changes in body weight and body composition. METHODS: Sixty-nine neonates were recruited among term infants in the University Hospital of Verona, Italy. Forty-nine subjects participated until follow-up. At birth and follow-up, weight and length were measured and arm-fat area and arm-muscle area were calculated from triceps and subscapular skinfolds. SEE and RQ were measured by indirect calorimetry. RESULTS: At birth, weight, length, arm-muscle and arm-fat areas were significantly higher in LGA subjects than in AGA subjects. Weight status, SEE and RQ at birth did not explain the relative weight change after adjusting for gestational weight, placental weight, age at follow-up and gender. Arm-fat area and weight/length ratio at birth were negatively associated with relative changes in body weight after adjusting for the above variables (p < 0.05). CONCLUSION: Early growth from birth to 5 mo of life is significantly affected by body size and adiposity at birth. Fatter newborns had a slower growth rate than thinner newborns.     

Visual evoked potentials in term light-for-gestational-age infants and infants of diabetic mothers

The latency and amplitude of the first negative peak of visual evoked potentials (VEP) were evaluated in 52 term infants, investigated within 48 h after birth. Sixteen were light-for-gestational-age (LGA), 16 were appropriate-for-gestational-age (AGA) and 20 were infants of diabetic mothers (IDM). The VEP latency was shorter in LGA infants compared to AGA infants, and it was closely related to the birth weight deviation. The VEP latency was inversely related to gestational age and positively related to head circumference. When corrected for gestational age and head circumference, the VEP latency was not significantly different between the subgroups, nor related to the birth weight deviation, ponderal index or skinfold thickness. Thus, it could be argued that the high conduction velocity in LGA infants is due to stress maturation or alternatively due to the smaller head circumference. The VEP amplitude was higher in LGA infants when compared with AGA infants, and inversely related to the birth weight deviation. No differences were found in VEP latency or VEP amplitude between IDM and AGA infants.     

脑源性神经营养因子与新生儿出生体重的关系

目的：该文通过检测新生儿脐血脑源性神经营养因子（brain-derived neurotrophic factor,BDNF）的水平,探讨BDNF与新生儿出生体重的关系,并对相关因素进行分析。方法：根据出生体重,将51 例足月第1胎健康新生儿分为3 组:①小于胎龄组（SGA）8例;②适于胎龄组（AGA ）31例;③大于胎龄组（LGA）12例。测量新生儿身长、体重及其母亲的身高、体重,并对脐血中BDNF、瘦素（LEP）、胰岛素（INS）、总胆固醇（TC）、甘油三酯（TG）进行检测。结果：SGA组的BDNF明显高于AGA组和大于LGA组,AGA组和LGA组中BDNF没有差异;多元逐步回归分析显示BDNF值与新生儿出生体重、体重指数存在负相关关系。LEP与BDNF不呈相关趋势（P>0.05）,INS与BDNF也不呈相关趋势（P>0.05）。INS 与LEP呈现正相关（P<0.05）。LEP与新生儿体重、产妇体重及其BMI呈正相关,而TC,TG在3组新生儿中差异无显著性。结论：BDNF是新生儿体重的重要影响因素,而且不受LEP,INS的影响。     

The relationship between birthweight, 25-hydroxyvitamin D concentrations and bone mineral status in neonates

BACKGROUND: Calcium (Ca), phosphorus (P) and 25-hydroxyvitamin D (25-OHD) are the major micronutrients for fetal skeletal development. AIMS: To compare whole body bone mineral density (WB BMD) and bone mineral content (WB BMC) in different birthweights of term neonates and to determine correlations of biological criteria of bone health between neonates and their mothers. SUBJECTS AND METHODS: Serum Ca, P, alkaline phosphatase (ALP) and 25-OHD levels were measured in 30 small-for-gestational-age (SGA, group 1), 40 appropriate-for-gestational-age (AGA, group 2) and 30 large-for-gestational-age (LGA, group 3) neonates and their mothers in winter. WB BMD and WB BMC of neonates were estimated by dual-energy X-ray absorptiometry (DEXA) in the 1st 24 hrs after delivery. RESULTS: Mean (SD) serum 25-OHD levels in the mothers [8.7 (3.0), 8.6 (3.0) and 7.7 (2.8) microg/L, respectively] and their infants [6.3 (2.5), 6.0 (2.2) and 5.7 (1.8) microg/L, respectively] in groups 1, 2 and 3 were similar. Compared with the mothers, the mean 25-OHD levels of the neonates in all groups were significantly lower (p<0.05), and they were highly correlated (r=0.755, p<0.05). Ninety-three per cent of the neonates and 82% of their mothers had 25-OHD levels <10 microg/L, the lowest limit of normal. Mean (SD) WB BMD and WB BMC were higher in LGA infants [0.442 (0.025) g/cm(2), 71.6 (9.0) g, p<0.01, p<0.001, respectively] but lower in SGA [0.381 (0.027) g/cm(2), 29.1 (9.1) g, p<0.001, p<0.001, respectively] than in AGA infants [0.426 (0.022) g/cm(2), 53.7 (9.6) g, respectively]. The percentage of WB BMC was lower in SGA than in AGA and LGA infants. WB BMC and WB BMD were positively correlated with birthweight (r=0.910, p<0.05) and gestational age (r=0.707, p<0.05) but not with serum 25-OHD. CONCLUSIONS: The neonates' bone indices increased significantly with gestational age and birthweight but this was not related to serum 25-OHD levels in the infants and their mothers.     

Risks of congenital anomalies in large for gestational age infants

OBJECTIVES: To evaluate the association between large for gestational age (LGA) and demographic and medical risk factors as well as specific types of congenital anomalies. STUDY DESIGN: A retrospective, case-control study on 2,149,617 consecutive births was conducted. LGA was defined as 1.64 SD above the mean weight for gestational age, adjusted by sex and altitude. Risk factor frequency distributions were compared between LGA and normal birth weight neonates. Associations between LGA and 41 infants with isolated congenital anomalies were evaluated. RESULTS: Of 31,897 neonates with congenital anomalies, 1800 were LGA. Five anomalies were associated with LGA: talipes calcaneovalgus, hydrocephaly, combined angiomatoses, hip subluxation, and non-brown-pigmented nevi. Multiparity, vaginal bleeding, diabetes, and delivery by cesarean section were more frequent in LGA than in appropriate for gestational age infants' mothers. Several maternal but no paternal factors were statistically associated with an increased risk for LGA infants. CONCLUSIONS: The clinical observation that nevi are more commonly observed in LGA patients was supported. The higher frequencies of hip subluxation and talipes calcaneovalgus among LGA neonates reinforces their pathogenesis as deformations, whereas those of combined angiomatoses and hydrocephaly could reflect increased fluid or body mass.     

The relationship between birth weight, oxidative stress and bone mineral status in newborn infants

BACKGROUND: It was shown that oxygen-derived free radicals, and particularly the superoxide anion, are intermediaries in the formation and activation of osteoclasts. Many antioxidant defence systems depend on micronutrients or are micronutrients themselves. Oxidative stress might be related to bone indices in newborn infants. AIM: To assess the relationship between oxidative status and bone indices in small-for-gestational-age (SGA), large-for-gestational-age (LGA) and appropriate-for-gestational-age (AGA) babies born to healthy mothers. METHODS: Umbilical cord venous blood samples were obtained at the delivery from 100 term newborn infants to measure plasma malondialdhyde, superoxide dismutase (SOD) and myeloperoxidase concentrations. Forty of the newborn infants had birth weights AGA, 30 were SGA and 30 LGA. Data were acquired using the whole body dual-energy X-ray absorptiometry scanner in the first 24 h after birth. RESULTS: Plasma malondialdhyde and SOD concentrations of the mothers and their newborn infants were positively correlated; however, plasma myeloperoxidase concentrations were not. SOD concentrations of SGA infants were significantly higher than those of AGA and LGA infants. Whole body bone mineral density and content were lower in SGA but higher in LGA babies than in AGA babies. Oxidative stress status of both infants and their mothers was not related to the bone indices. CONCLUSION: Our study does not provide support for the hypothesis that oxidative status of the infants and mothers may play a major role in the regulation of bone metabolism in the developing skeleton.     

Longitudinal investigation of the relationship between breast milk leptin levels and growth in breast-fed infants

BACKGROUND: It has been shown that leptin is present in breast milk and human mammary epithelial cells are able to synthesize leptin. It has been suggested that leptin in human milk might be involved in the regulation of postnatal nutrition and growth. AIMS: To investigate whether there is a relationship between leptin levels in human milk and weight gain in the postnatal period and to compare variations of milk-borne maternal leptin concentrations for small for gestational age (SGA), large for gestational age (LGA) and appropriate for gestational age (AGA) infants. INFANTS AND METHODS: Forty-seven healthy lactating women aged from 17-38 years and their infants were included in the study. The infants were separated into three groups according to birth weight as SGA (n = 11), LGA (n = 14) and AGA (n = 22). All infants were fed with breast milk during the study period. Anthropometric measurements were performed on the 15th day of life and at 1, 2, and 3 months of age, and the body mass index (BMI) of the infants' mothers was calculated. Breast milk leptin levels were analyzed by radioimmunoassay. RESULTS: Breast milk leptin levels were found reduced in the SGA group and increased in the LGA group compared to the AGA group at 15 days of life (13.4 +/- 2.2, 28.5 +/- 4.4 and 18.4 +/- 2 ng/ml, respectively; p <0.05). At 1 month of age, leptin levels in breast milk were significantly lower in the LGA group than in the AGA group (15.5 +/- 4.9, 19.4 +/- 1.7 ng/ml, respectively; p<0.05). There was no difference among the three groups at 2 and 3 months of age (p>0.05). There was a positive correlation between birth Weight and breast milk leptin levels on the 15th day (r = 0.47, p = 0.001). A negative correlation was found between weight gain during the first 15 days and 1 month of life and breast milk leptin levels on the 15th day (r = -0.44, p = 0.002; r = -0.40, p = 0.005, respectively). No relationship could be determined between breast milk leptin levels and BMI of the mothers. CONCLUSION: Maternal milk of SGA, LGA and AGA infants had different leptin levels, especially during the first month of life. More rapid growth was shown in the SGA infants during the first postnatal 15 days compared to AGA and LGA infants, and human milk leptin levels were significantly reduced in the SGA group. However, LGA infants gained more weight during the second 15 days of life and breast milk leptin levels were dramatically decreased in LGA and increased in SGA infants at the end of first month of life. These findings suggest that the presence of leptin in breast milk might have a significant role in growth, appetite and regulation of nutrition in infancy, especially during the early lactation period, and the production of leptin in breast tissue by human mammary epithelial cells might be regulated physiologically according to necessity and state of the infant.     

Cord prealbumin values in newborn infants: effect of prenatal steroids, pulmonary maturity, and size for dates

We assessed cord prealbumin concentrations in 214 appropriate for gestational age newborn infants, 21 small for gestational age infants, and 27 large for gestational age infants to establish normal values and to assess the effect of intrauterine growth, prenatal steroids, and pulmonary maturity on prealbumin levels. Cord prealbumin values were significantly correlated with increasing gestational age (r = 0.33; P less than 0.001) and birth weight (r = 0.40, P less than 0.001) in the AGA neonates. Neonates born before 37 weeks gestation had significantly lower prealbumin levels than those born at term (P less than 0.001). The SGA infants had significantly lower levels than age-matched AGA controls (P less than 0.01), and LGA infants had significantly higher levels than age-matched AGA controls (P less than 0.001). In preterm infants, those with exposure to prenatal steroids (betamethasone or premature rupture of membranes) had significantly higher prealbumin values than control infants of comparable age and weight (P less than 0.001). Infants without respiratory distress syndrome had higher levels than those of comparable age and weight with hyaline membrane disease (P less than 0.05). This study demonstrates that a correlation of gestational age and birth weight exists with cord prealbumin levels, and that the large variability at each gestational age may be accounted for in part by appropriateness of size for dates, prenatal steroid exposure, and pulmonary maturity.     

Body water content of extremely preterm infants at birth

BACKGROUND: Preterm birth is often associated with impaired growth. Small for gestational age status confers additional risk. AIM: To determine the body water content of appropriately grown (AGA) and small for gestational age (SGA) preterm infants in order to provide a baseline for longitudinal studies of growth after preterm birth. METHODS: All infants born at the Hammersmith and Queen Charlotte's Hospitals between 25 and 30 weeks gestational age were eligible for entry into the study. Informed parental consent was obtained as soon after delivery as possible, after which the extracellular fluid content was determined by bromide dilution and total body water by H(2)(18)O dilution. RESULTS: Forty two preterm infants were studied. SGA infants had a significantly higher body water content than AGA infants (906 (833-954) and 844 (637-958) ml/kg respectively; median (range); p = 0.019). There were no differences in extracellular and intracellular fluid volumes, nor in the ratio of extracellular to intracellular fluid. Estimates of relative adiposity suggest a body fat content of about 7% in AGA infants, assuming negligible fat content in SGA infants and lean body tissue hydration to be equivalent in the two groups. CONCLUSIONS: Novel values for the body water composition of the SGA preterm infant at 25-30 weeks gestation are presented. The data do not support the view that SGA infants have extracellular dehydration, nor is their regulation of body water impaired.     

多中心大于胎龄儿新生儿期死亡原因及风险的病例对照研究

目的探讨大于胎龄儿（LGA）新生儿期死亡原因及死亡风险。方法病例对照研究。《中国新生儿死亡原因多中心调查》数据库包括39家三级医院新生儿科胎龄≥24周的所有死亡病例数据，以数据库中的LGA为病例组（单胎出生，晚期早产儿或足月儿），分别以数据库中全部适于胎龄儿（AGA）和配对的AGA（1∶1）为对照组（匹配条件：单胎、胎龄、性别、来源医院），比较LGA和AGA新生儿期死亡原因。通过整体人群中LGA和AGA活产婴儿比例，估计整体人群LGA死亡风险。采集母亲因素、围生期因素、新生儿因素和死亡原因。根据WHO ICD-PM分类标准分为11类新生儿期死亡原因。结果2016年7月1日至2019年6月30日数据库中新生儿期死亡的LGA和AGA分别为126和1 183例。LGA组新生儿除出生体重、母亲妊娠期糖尿病患病率外均与匹配AGA组差异无统计学意义。多因素回归分析，矫正出生体重和妊娠期糖尿病因素，LGA组早期新生儿死亡风险较匹配AGA组增加1.94倍（OR=2.938，95%CI: 1.346~6.416,P=0.007）。LGA的主要死亡原因排序为先天性疾病（29.4%）、围产期窒息（21.4%）、呼吸系统疾病和心血管疾病（14.3%）、重症感染（11.9%）。LGA组新生儿全因死亡风险与匹配AGA组差异无统计学意义，LGA组死于重症感染（N6：细菌性败血症,细菌脑膜炎，肺炎，病毒感染等）的风险低于匹配AGA组（OR=0.541，95%CI：0.320~0.912，P=0.019）。结论国内三级医院晚期早产儿和足月单胎LGA的主要死亡原因构成及其比例与AGA相比总体一致，LGA并不增加新生儿期的死亡风险，且死于重症感染风险低于AGA。     

多中心大于胎龄儿新生儿期死亡原因及风险的病例对照研究

目的探讨大于胎龄儿（LGA）新生儿期死亡原因及死亡风险。方法病例对照研究。《中国新生儿死亡原因多中心调查》数据库包括39家三级医院新生儿科胎龄≥24周的所有死亡病例数据,以数据库中的LGA为病例组（单胎出生,晚期早产儿或足月儿）,分别以数据库中全部适于胎龄儿（AGA）和配对的AGA（1∶1）为对照组（匹配条件：单胎、胎龄、性别、来源医院）,比较LGA和AGA新生儿期死亡原因。通过整体人群中LGA和AGA活产婴儿比例,估计整体人群LGA死亡风险。采集母亲因素、围生期因素、新生儿因素和死亡原因。根据WHO ICD-PM分类标准分为11类新生儿期死亡原因。结果2016年7月1日至2019年6月30日数据库中新生儿期死亡的LGA和AGA分别为126和1 183例。LGA组新生儿除出生体重、母亲妊娠期糖尿病患病率外均与匹配AGA组差异无统计学意义。多因素回归分析,矫正出生体重和妊娠期糖尿病因素,LGA组早期新生儿死亡风险较匹配AGA组增加1.94倍（OR=2.938,95%CI: 1.346~6.416,P=0.007）。LGA的主要死亡原因排序为先天性疾病（29.4%）、围产期窒息（21.4%）、呼吸系统疾病和心血管疾病（14.3%）、重症感染（11.9%）。LGA组新生儿全因死亡风险与匹配AGA组差异无统计学意义,LGA组死于重症感染（N6：细菌性败血症,细菌脑膜炎,肺炎,病毒感染等）的风险低于匹配AGA组（OR=0.541,95%CI：0.320~0.912,P=0.019）。结论国内三级医院晚期早产儿和足月单胎LGA的主要死亡原因构成及其比例与AGA相比总体一致,LGA并不增加新生儿期的死亡风险,且死于重症感染风险低于AGA。     

Total energy expenditure in small for gestational age infants.

OBJECTIVE: To measure total energy expenditure and body composition in small for gestational age (SGA) infants, to investigate hypermetabolism. METHODS: A cross-sectional study was performed in 52 small for gestational age (SGA) measured at 5 weeks of age, using existing data from appropriate for gestational age (AGA) infants as controls. The doubly-labelled water technique was used to assess both total energy expenditure and body composition in both cohorts of infants. RESULTS: Multiple regression analysis revealed that expressing energy expenditure per kg fat free mass adjusts for body composition in infants of this age. Regression analysis also showed that the relation between total energy expenditure and fat free mass differed between the two groups. CONCLUSION: These data indicate that for a given fat free mass, the total energy expenditure of SGA infants is greater than that of AGA infants. Such data should be taken into account when energy requirements for SGA infants are being considered.     

Total energy expenditure in small for gestational age infants.

AIM: To measure total energy expenditure and body composition in small for gestational age (SGA) infants in order to investigate proposed hypermetabolism in such babies. METHODS: A cross sectional study of 52 SGA infants measured at 5 weeks of age was made, using existing data from appropriate for gestational age (AGA) infants as controls. The double labelled water technique was used to assess both total energy expenditure and body composition. RESULTS: Multiple regression analysis showed that expressing energy expenditure per kg fat free mass adjusts for body composition in infants of this age. The relation between total energy expenditure and fat free mass differed between the two groups. CONCLUSION: These data indicate that for a given fat free mass the total energy expenditure of SGA infants is greater than that of AGA infants. Such data should be taken into account when energy requirements for SGA infants are being considered.