Relations among maternal physical activity during pregnancy and child body composition.

OBJECTIVE: Physical activity (PA) during pregnancy is associated with lower neonatal fat mass, but associations with child body composition are mixed. The purpose of this study was to examine associations between trimester-specific pregnancy PA and child body composition at 4 years. METHODS: Participants of the Minnesota Infant Nutrition, Neurodevelopment, and Obesity Study were asked to recall participation in any moderate or vigorous PA in the first (T1), second (T2) and third (T3) trimesters at about 5 years postpartum. Child fat mass and fat-free mass were measured via air displacement plethysmography at 2 weeks, 3 months and 4 years of age. Multivariate linear regression was used for analyses. RESULTS: Of 51 possible participants, 37 recalled pregnancy PA. Any vigorous PA in T3 was associated with lower child fat mass at 4 years (adjß = -1.077, p < 0.05). CONCLUSION: Late pregnancy PA may have lasting benefits for child body composition. Replication of these findings is needed in a larger sample with prospective measures.

Do anthropometric measures accurately reflect body composition in preterm infants?

BACKGROUND: Recent literature suggests that neonatal adiposity is predictive of later metabolic health, while neonatal lean mass is predictive of later cognitive function amongst preterm infants. Anthropometric indices that accurately reflect neonatal body composition could improve clinical care and aid future research, but their validity has not been systematically tested in preterm infants. OBJECTIVE: To determine the weight/length indices that best reflect neonatal body composition in preterm infants. METHODS: Weight and length were measured, and body composition (fat-free mass (FFM), fat mass (FM) and percent body fat (%BF)) was assessed using air-displacement plethysmography within 72 h of birth in 218 preterm infants. The best weight/length proxy for FFM, FM and %BF were those with the highest proportion variance explained (R2 ) and lowest root mean square error (RMSE) in linear regression models. RESULTS: Among all of the weight/length indices tested, weight/length2 was the best proxy for %BF, but nonetheless exhibited very low variance explained (R2 = 0.27) and high prediction error (RMSE = 3.5% fat). Body weight unadjusted for length was strongly associated with FFM (R2 = 0.97). CONCLUSIONS: No weight/length index accurately reflected %BF. Weight/length indices are not appropriate for assessment of relative adiposity in preterm infants near birth. What's known on this subject: Compared with term infants, preterm infants have increased fat mass and diminished fat-free mass upon hospital discharge. Early adiposity predicts later metabolic health, while early lean mass is predictive of later neurodevelopmental outcomes. Optimal anthropometric proxies for preterm body composition at birth are not established. WHAT THIS STUDY ADDS: Weight is an adequate surrogate for lean mass at birth in preterm infants. There are no weight/length indices that accurately reflect neonatal adiposity at birth.

Diminished growth and lower adiposity in hyperglycemic very low birth weight neonates at 4 months corrected age.

OBJECTIVE: Characterize the relationship between neonatal hyperglycemia and growth and body composition at 4 months corrected age (CA) in very low birth weight (VLBW) preterm infants. STUDY DESIGN: A prospective study of VLBW appropriate-for-gestation infants (N=53). All blood glucose measurements in the first 14 days and nutritional intake and illness markers until discharge were recorded. Standard anthropometrics and body composition via air displacement plethysmography were measured near term CA and 4 months CA. Relationships between hyperglycemia and anthropometrics and body composition were examined using multivariate linear regression. RESULTS: Infants with >5 days of hyperglycemia were lighter (5345 vs 6455 g, P⩽0.001), shorter (57.9 vs 60.9 cm, P⩽0.01), had smaller occipital-frontal head circumference (39.4 vs 42.0 cm, P⩽0.05) and were leaner (percent body fat 15.0 vs 23.8, P⩽0.01) at 4 months CA than those who did not have hyperglycemia, including after correcting for nutritional and illness factors. CONCLUSIONS: Neonatal hyperglycemia in VLBW infants is associated with decreased body size and lower adiposity at 4 months CA independent of nutritional deficit, insulin use and illness. Downregulation of the growth hormone axis may be responsible. These changes may influence long-term growth and cognitive development.

Body composition at birth in preterm infants between 30 and 36 weeks gestation.

BACKGROUND: The American Academy of Pediatrics calls for aggressive management of preterm infants to achieve body composition approximating that of the healthy infant in utero. Air displacement plethysmography (ADP) has been validated for assessment of body composition in preterm infants and could be used to monitor their nutritional status during hospitalization. Comparative datasets on body composition at birth among healthy, live-born preterm infants are lacking. OBJECTIVE: The aim of this study is to provide the first descriptive fat mass (FM) and fat-free mass (FFM) data from healthy newborn preterm infants at birth as a proxy for healthy in utero body composition. METHODS: Body mass and volume were obtained using ADP within 72 h of birth in 98 singleton, appropriate-for-gestational-age preterm infants. FM and FFM were calculated using the Fomon equation. RESULTS: Measurement with ADP was feasible and well tolerated by infants as young as 30 weeks gestation and <72 h of age. FFM and FM increased linearly over the gestational age range period at rates of 171 and 46 g week(-1) , respectively. Mean values obtained by ADP by gestational week were similar to the previously published reference data from chemical analysis on stillbirths. CONCLUSIONS: Body composition assessment using ADP is feasible in newborn preterm infants and provides group estimates similar to that of the reference fetus. In the future, integrating body composition information into the nutritional management of preterm infants may help to identify new strategies to optimize growth and development in this vulnerable population.

Neonatal hyperglycemia and diminished long-term growth in very low birth weight preterm infants.

OBJECTIVE: To investigate the association between early hyperglycemia and growth and development from hospital discharge to 2 years corrected age (CA) in very low birth weight (VLBW) infants. STUDY DESIGN: Blood glucose levels during the first 14 days after birth, weight, length and occipital-frontal circumference (OFC) at birth, hospital discharge and 4, 12 and 24 months CA, Bayley developmental scores at 12 and 24 months CA, and information on multiple clinical variables were recorded on VLBW preterm infants (N=80). The relationships between hyperglycemia, growth and developmental scores were determined using linear mixed effects regression. RESULT: Hyperglycemia was a strong predictor of poor rate of increase in weight, length and OFC until 24 months CA. Hyperglycemia was not associated with lower scores on the Bayley scales. CONCLUSION: Neonatal hyperglycemia was associated with poor physical growth until at least 2 years CA in this cohort of VLBW preterm infants.