Limbs Anthropometry of Singleton Chinese Newborns of 28–42 Weeks’ Gestation

Trade-offs in relative limb length among Peruvian children: extending the thrifty phenotype hypothesis to limb proportions

Background and Methods

Both the concept of ‘brain-sparing’ growth and associations between relative lower limb length, childhood environment and adult disease risk are well established. Furthermore, tibia length is suggested to be particularly plastic under conditions of environmental stress. The mechanisms responsible are uncertain, but three hypotheses may be relevant. The ‘thrifty phenotype’ assumes that some components of growth are selectively sacrificed to preserve more critical outcomes, like the brain. The ‘distal blood flow’ hypothesis assumes that blood nutrients decline with distance from the heart, and hence may affect limbs in relation to basic body geometry. Temperature adaptation predicts a gradient of decreased size along the limbs reflecting decreasing tissue temperature/blood flow. We examined these questions by comparing the size of body segments among Peruvian children born and raised in differentially stressful environments. In a cross-sectional sample of children aged 6 months to 14 years (n = 447) we measured head circumference, head-trunk height, total upper and lower limb lengths, and zeugopod (ulna and tibia) and autopod (hand and foot) lengths.

Results

Highland children (exposed to greater stress) had significantly shorter limbs and zeugopod and autopod elements than lowland children, while differences in head-trunk height were smaller. Zeugopod elements appeared most sensitive to environmental conditions, as they were relatively shorter among highland children than their respective autopod elements.

Discussion

The results suggest that functional traits (hand, foot, and head) may be partially protected at the expense of the tibia and ulna. The results do not fit the predictions of the distal blood flow and temperature adaptation models as explanations for relative limb segment growth under stress conditions. Rather, our data support the extension of the thrifty phenotype hypothesis to limb growth, and suggest that certain elements of limb growth may be sacrificed under tough conditions to buffer more functional traits.

Relationship between maternal and newborn anthropometric measurements in Sudan

BACKGROUND

The aim of the present study was to investigate the relationship between maternal and newborn anthropometry.

METHODS

In 1000 Sudanese mothers and newborns anthropometric measurements were taken within 24 h of birth. The relationship between maternal characteristics including age, years of education, social class and anthropometry, and newborn characteristics including gestational age, weight, body length, body circumference and skin-fold thickness, was investigated on multiple regression with backward selection, and multivariate anova (where appropriate) to identify the most important associations.

RESULTS

Maternal age and anthropometry were significantly associated with newborn anthropometry to a variable extent. The strongest associations (R2 > 5-6%) were found for mid-arm circumference, supine length and birthweight. The postpartum maternal lean body mass (LBM) was significantly associated with birthweight, body length and body circumference (P < 0.001), while skin-fold thickness was mainly associated with maternal age and maternal body mass index (BMI). Gestational age was only weakly associated with the maternal height (R2 > 1.3%) and the association between maternal anthropometry and the ponderal index (PI) of the newborn was negligible (R2 < 1%). Maternal education was significantly associated with birthweight and body circumference (except the abdominal), and the PI and the latter increased significantly with increasing number of years of education. No association between social class and newborn anthropometry was obtained.

CONCLUSION

There was a significant association between maternal LBM and newborn size and between maternal BMI and newborn fat stores. Maternal education and not social class was associated with newborn size.

The search for objective criteria at the limit of viability

BACKGROUND

Defining the limit of viability among very preterm infants remains a difficult issue. A recent study suggested severity of intrauterine growth retardation as a decisive criterion, reporting very poor survival for infants born at </=28 weeks with birth weight <2nd centile.

OBJECTIVE

To check whether the above criterion can be confirmed in a similar analysis of German data.

METHODS

Analyses were based on German population-based data from Lower Saxony, including preterm neonates (22-28 weeks) without severe congenital malformations (n = 3,453), born 1991-1999. For the definition of growth retardation postnatal (<3rd, <10th centile) and antenatal (<3rd centile) reference values were used.

RESULTS

Depending on the definition used, proportions of growth retarded infants varied considerably (4-16%). Survival rates increased from 0 to 64%, arguing against considering infants <28 weeks' GA as a homogenous group with regard to their odds for survival.

CONCLUSION

There is an association between severity of growth retardation and VLBW mortality in general, but overinterpreting results from single studies may lead to dangerous conclusions. Data from preterm infants should be stratified by week of gestation.

Normative data for triceps and subscapular skinfold thicknesses of Chinese infants

Skinfold thickness is a validated parameter of subcutaneous fat accumulation. Data on triceps and subscapular skinfold thicknesses were collected from 10,043 (5318 males, 4725 females) singletons at 12 hospitals with gestation 31-42 wk. The LMS method using maximum penalized likelihood was used to perform model fitting of the anthropometric centiles for these parameters. Both triceps and subscapular skinfold thicknesses were greater in girls than in boys. Racial differences were found when comparing with other populations. The triceps subscapular skinfold thicknesses of Chinese infants were significantly lower than those of US white infants but larger than those of African-American infants, Israeli infants, Spanish infants and Indian infants.

CONCLUSION

This study provides the first set of references for the triceps and subscapular skinfold thicknesses of Chinese infants by gestation and gender. These data are helpful in determining the nutritional status of infants at birth and in assessing the postnatal growth of Chinese infants.