The impact of the Covid-19 lockdown on the experiences and feeding practices of new mothers in the UK: Preliminary data from the COVID-19 New Mum Study.

BACKGROUND: The COVID-19 New Mum Study is recording maternal experiences and infant feeding during the UK lockdown. This report from week 1 of the survey describes and compares the delivery and post-natal experiences of women who delivered before (BL) versus during (DL) the lockdown. METHODS: Women living in the UK aged ≥18 years with an infant ≤12 months of age completed an anonymous online survey (https://is.gd/covid19newmumstudy). Information/links are shared via websites, social media and existing contacts. RESULTS: From 27.5.20-3.6.20, 1365 women provided data (94% white, 95% married/with partner, 66% degree/higher qualification, 86% living in house; 1049 (77%) delivered BL and 316 (23%) DL. Delivery mode, skin-to-skin contact and breastfeeding initiation did not differ between groups. DL women had shorter hospital stays (p < 0.001). 39% reported changes to their birth plan. Reflecting younger infant age, 59% of DL infants were exclusively breast-fed/mixed fed versus 39% of BL (p < 0.05). 13% reported a change in feeding; often related to lack of breastfeeding support, especially with practical problems. Important sources of feeding support were the partner (60%), health professional (50%) and online groups (47%). 45% of DL women reported insufficient feeding support. Among BL women, 57% and 69% reported decreased feeding support and childcare, respectively. 40% BL/45% DL women reported insufficient support with their own health, 8%/9% contacted a mental health professional; 11% reported their mental health was affected. 9% highlighted lack of contact/support from family and distress that they had missed seeing the baby. CONCLUSION: Lockdown has impacted maternal experiences, resulting in distress for many women. Our findings suggest the need for better infant feeding support, especially 'face-to-face' support for practical issues; and recognising and supporting mothers who are struggling with mental health challenges or other aspects of their health. The effectiveness of online versus face-to-face contact is currently uncertain, and requires further evaluation.

Body mass index adjustments to increase the validity of body fatness assessment in UK Black African and South Asian children.

BACKGROUND/OBJECTIVES: Body mass index (BMI) (weight per height2) is the most widely used marker of childhood obesity and total body fatness (BF). However, its validity is limited, especially in children of South Asian and Black African origins. We aimed to quantify BMI adjustments needed for UK children of Black African and South Asian origins so that adjusted BMI related to BF in the same way as for White European children. METHODS: We used data from four recent UK studies that made deuterium dilution BF measurements in UK children of White European, South Asian and Black African origins. A height-standardized fat mass index (FMI) was derived to represent BF. Linear regression models were then fitted, separately for boys and girls, to quantify ethnic differences in BMI-FMI relationships and to provide ethnic-specific BMI adjustments. RESULTS: We restricted analyses to 4-12 year olds, to whom a single consistent FMI (fat mass per height5) could be applied. BMI consistently underestimated BF in South Asians, requiring positive BMI adjustments of +1.12 kg m-2 (95% confidence interval (CI): 0.83, 1.41 kg m-2; P<0.0001) for boys and +1.07 kg m-2 (95% CI: 0.74, 1.39 kg m-2; P<0.0001) for girls of all age groups and FMI levels. BMI overestimated BF in Black Africans, requiring negative BMI adjustments for Black African children. However, these were complex because there were statistically significant interactions between Black African ethnicity and FMI (P=0.004 boys; P=0.003 girls) and also between FMI and age group (P<0.0001 for boys and girls). BMI adjustments therefore varied by age group and FMI level (and indirectly BMI); the largest adjustments were in younger children with higher unadjusted BMI and the smallest in older children with lower unadjusted BMI. CONCLUSIONS: BMI underestimated BF in South Asians and overestimated BF in Black Africans. Ethnic-specific adjustments, increasing BMI in South Asians and reducing BMI in Black Africans, can improve the accuracy of BF assessment in these children.

Breast-feeding and formula feeding in healthy term infants and bone health at age 10 years.

Few studies have investigated the effects of infant nutrition on later bone health in term infants, although low sn-2 palmitate in infant formulas has been shown to result in the formation of stool fatty acid soaps, reduced Ca absorption and lower bone mass in the short term. To investigate the effect of (1) breast-feeding (BF) and (2) the type of infant formula (standard fat blend v. high-sn-2 fat blend) on bone mass at age 10 years, anthropometry and bone mass (from dual-energy X-ray absorptiometry (GE Lunar Prodigy); lumbar spine (LS) and total body less head; adjusted for size (bone mineral apparent density standard deviation score (SDS) and regression)) were measured in 10-year-old subjects born at term and either breast-fed (n 34) or randomised to a standard control formula (n 27) or a high-sn-2 palmitate formula (n 30) for the first 12 weeks of life. At follow-up, previously BF children were older but lighter (by 0·5 SDS, P= 0·03) than formula-fed children with a lower LS bone mineral density SDS (by 0·44, P= 0·03), but size-adjusted bone mass did not differ. There were no significant differences in bone mass between the formula-fed groups. These findings suggest that there is no significant effect of BF or high-sn-2 infant formula on size-adjusted bone mass in mid-childhood, and that the effects of infant nutrition on bone mass previously reported may be confined to the short term. A larger study would be required to exclude smaller effects.

Clinical safety assessment of infant nutrition.

Data on clinical safety and efficacy are ideally collected in a randomized clinical trial or, failing this, an observational study. Suitable outcomes vary depending on the intervention and population group, and certain outcomes such as growth may test both efficacy and safety. The use of growth as an important safety outcome has some limitations since it is currently not clear what represents an 'optimal' growth pattern. Several issues currently make the conduct and interpretation of infant nutrition trials challenging. These include difficulties in recruiting exclusively formula-fed infants, particularly given the emotive nature of infant feeding; the involvement of industry leading to real or perceived conflicts of interest; increased regulation and bureaucracy; and particular issues with long-term follow-up studies, notably cohort attrition. This paper addresses the implications of these issues and some potential solutions.

Prenatal and postnatal programming of body composition in obese children and adolescents: evidence from anthropometry, DXA and the 4-component model.

BACKGROUND: Low-birth weight has been proposed to programme central adiposity in childhood. However, there is little information on associations between fetal weight gain and fat distribution within obese individuals. OBJECTIVES: To investigate associations between birth weight and postnatal weight gain with body composition in a sample of obese children and adolescents. SUBJECTS AND METHODS: Body composition was measured using anthropometry, dual-emission X-ray absorptiometry and the 4-component model in 45 male and 76 female obese individuals aged 5-22 years. General linear models were used to investigate associations between birth weight standard deviation score (SDS), or change in weight SDS between birth and follow-up, and body composition, adjusting for age, pubertal status, height and gender. RESULTS: Birth weight SDS ranged from -1.86 to 3.46, and was inversely associated with current weight SDS after adjustment for height SDS. Birth weight SDS was weakly associated with waist and hip girths, but not waist-hip ratio or trunk fat, after adjusting for age, height, pubertal status and gender. Change in weight SDS was strongly associated with total and central adiposity. CONCLUSIONS: Despite incorporating substantial variability, birth weight SDS was only a weak predictor of tissue masses and their distribution in obese children. Variability in central adiposity was more strongly associated with the magnitude of postnatal growth, which in turn was weakly inversely associated with birth weight SDS. In a population uniformly characterised by excess body weight, postnatal weight gain exerted the dominant impact on adiposity and fat distribution.

Association between infant correlates of impulsivity--surgency (extraversion)--and early infant growth.

Increasing evidence suggests that rapid postnatal weight gain is associated with increased risks of being overweight or obese later in life and of co-morbidities, such as diabetes, the metabolic syndrome and cardiovascular disease. In children as young as two years of age, as well as in adults, an appetitive system-linked impulsivity trait has been demonstrated to be linked with increased overweight, and postulated to act via increased food intake, through greater responsiveness to food and lower self-inhibitory control skills. In this study, we hypothesized that growth in infancy, a critical window for metabolic programming, would be predicted by measures of infant surgency/extraversion, assessed using the Rothbart Infant Behaviour Questionnaire (revised version). Anthropometry was measured at birth and at 3, 6 and 12 months, and weight gains expressed as increases in standardized scores, allowing for adjustment for gender and age, including gestational age. We used conditional weight (CW), a residual of current weight regressed on prior weights, to represent deviations from expected weight gains, from 0 to 3, 3 to 6 and 6 to 12 months. Controlling for significant sociodemographic correlations, multiple regression analyses showed significant prediction of CWs at 3 months but not of CWs at 6 or 12 months by surgency/extraversion. These pilot findings of association between infant growth, during a critical period, and surgency/extraversion, early correlates of impulsivity, warrant further investigation, to ascertain implications for childhood and later weight and body composition.

Evaluation of DXA against the four-component model of body composition in obese children and adolescents aged 5-21 years.

BACKGROUND: Body composition is increasingly measured in pediatric obese patients. Although dual-energy X-ray absorptiometry (DXA) is widely available, and is precise, its accuracy for body composition assessment in obese children remains untested. OBJECTIVE: We aimed to evaluate DXA against the four-component (4C) model in obese children and adolescents in both cross-sectional and longitudinal contexts. DESIGN: Body composition was measured by DXA (Lunar Prodigy) and the 4C model in 174 obese individuals aged 5-21 years, of whom 66 had a second measurement within 1.4 years. The Bland-Altman method was used to assess agreement between techniques for baseline body composition and change therein. RESULTS: A significant minority of individuals (n=21) could not be scanned successfully due to their large size. At baseline, in 153 individuals with complete data, DXA significantly overestimated fat mass (FM; Delta=0.9, s.d. 2.1 kg, P<0.0001) and underestimated lean mass (LM; Delta=-1.0, s.d. 2.1 kg, P<0.0001). Multiple regression analysis showed that gender, puberty status, LM and FM were associated with the magnitude of the bias. In the longitudinal study of 51 individuals, the mean bias in change in fat or LM did not differ significantly from zero (FM: Delta=-0.02, P=0.9; LM: Delta=0.04, P=0.8), however limits of agreement were wide (FM: +/-3.2 kg; LM: +/-3.0 kg). The proportion of variance in the reference values explained by DXA was 76% for change in FM and 43% for change in LM. CONCLUSIONS: There are limitations to the accuracy of DXA using Lunar Prodigy for assessing body composition or changes therein in obese children. The causes of differential bias include variability in the magnitude of tissue masses, and stage of pubertal development. Further work is required to evaluate this scenario for other DXA models and manufacturers.

Bioelectric impedance vector analysis (BIVA) in hospitalised children; predictors and associations with clinical outcomes.

BACKGROUND: Clinical use of bioelectric impedance is limited by variability in hydration. Analysis of raw bioelectric impedance vectors (BIVA), resistance (R), reactance (Xc) and phase angle (PA) may be an alternative for monitoring disease progression/treatment. Clinical experience of BIVA in children is limited. We investigated predictors of BIVA and their ability to predict clinical outcomes in children with complex diagnoses. METHODS: R, Xc and PA were measured (BODYSTAT Quadscan 4000) on admission in 108 patients (4.6-16.8 years, mean 10.0). R and Xc were indexed by height (H) and BIVA-SDS for age and sex calculated using data from healthy children. Potential predictors and clinical outcomes (greater-than-expected length-of-stay (LOS), complications) were recorded. RESULTS: Mean R/H-SDS was significantly higher (0.99 (SD 1.32)) and PA-SDS lower (-1.22 (1.68))) than expected, with a wide range for all parameters. In multivariate models, the Strongkids risk category predicted R/H-SDS (adjusted mean for low, medium and high risk = 0.49, 1.28, 2.17, p = 0.009) and PA-SDS (adjusted mean -0.52, -1.53, -2.36, p = 0.01). BIVA-SDS were not significantly different in patients with or without adverse outcomes. CONCLUSIONS: These complex patients had abnormal mean BIVA-SDS suggestive of reduced hydration and poor cellular health according to conventional interpretation. R/H-SDS was higher and PA-SDS lower in those classified as higher malnutrition risk by the StrongKids tool. Further investigation in specific patient groups, including those with acute fluid shifts and using disease-specific outcomes, may better define the clinical role of BIV.

Reduction in bone mineral density in glycogenosis type III may be due to a mixed muscle and bone deficit.

UNLABELLED: Glycogen storage disease type III (GSD III; OMIM 232400) is an autosomal recessive deficiency of the glycogen debrancher enzyme, amylo-1,6-glucosidase (EC 3.2.1.33). Patients with other hepatic glycogenoses are known to have reduced bone mineral content (BMC) and to be at consequent risk of fractures. They have key metabolic differences from GSD III patients, however. This study examines bone density and metabolism in 15 GSD III patients (6 female) from childhood to adulthood (aged 10-34 years). The results demonstrate that patients with GSD III have low bone mass at all skeletal sites compared with healthy individuals of the same age and sex, with a significant proportion (40-64%) having BMD > 2 standard deviations below the mean for whole body and lumbar spine. The deficiency seems to be attributable to a mixed muscle andbone deficit. Lower bone mass was found at all sites for GSD IIIa patients (combined liver and muscle defect) compared with GSD IIIb patients (liver only defect). CONCLUSION: Patients with GSD III have significantly abnormal bone mass, placing them at increased risk of potential fracture. The underlying mechanism is probably multifactorial with contributions from abnormal muscle physiology, abnormal metabolic milieu and altered nutrition affecting micronutrient intake. Therapies need to address all these factors to be successful.

Undercarboxylated osteocalcin and bone mass in 8-12 year old children with cystic fibrosis.

UNLABELLED: Young adults with cystic fibrosis (CF) frequently develop bone disease. One suggested aetiological factor is suboptimal vitamin K status with impaired carboxylation of osteocalcin and abnormal bone formation. METHODS: We measured bone mineralization and turnover in thirty-two 8-12 year old CF patients (14 boys) using Dual Energy X-ray absorptiometry (whole body (WB) and lumbar spine (LS)), 25-OH Vitamin D, PTH and markers of bone formation (plasma osteocalcin, N-terminal pro-peptide of type 1 collagen (P1NP)), plus an indirect measure of vitamin K status, undercarboxylated osteocalcin (uc-OC). RESULTS: LS bone mineral density (BMD) standard deviation (SD) scores were < -1.0 in 20% of subjects. Size-adjusted LS and WB bone mass was normal. Compared to reference data, % uc-OC was high and P1NP low. LS bone mass was predicted by % uc-OC but not other markers (0.4% decrease in size-adjusted LSBMC (p=0.05); 0.04 SD decrease in LSBMAD (p=0.04) per 1% increase in uc-OC). CONCLUSION: Markers suggestive of sub-optimal vitamin K status and low bone formation were present despite normal size-adjusted bone mass. The association between LSBMC and % uc-OC is consistent with the hypothesis that sub-optimal vitamin K status is a risk factor for CF bone disease. This should ideally be investigated in an intervention trial.

Quantitative ultrasound (QUS): a useful tool for monitoring bone health in preterm infants?

UNLABELLED: Preterm infants are at risk of osteopenia and metabolic bone disease (MBD) of prematurity. There is a need for simple, reliable methods to detect and monitor this condition. AIMS: The aims were first to describe longitudinal changes in speed of sound (SOS) measured using quantitative ultrasound (QUS; Sunlight Omnisense, Israel) in preterm neonates: and second to determine whether SOS predicts the development of MBD. METHODS: SOS was measured in the tibia in 99 preterm infants (mean (SD)) gestation 29.7 (3.6) weeks; birthweight 1340 (550) g, with longitudinal measurements in 75. SOS z-scores were generated for gestation and sex. Clinical data were recorded. RESULTS: Baseline SOS (but not SOS z-score) was positively associated with gestational age. SOS and SOS z-score fell with age. In multivariate models, peak ALP, minimum phosphate concentrations and markers of illness severity were not predictors of the fall in SOS z-score, and baseline SOS measurements did not predict the development of high peak ALP or low phosphate. INTERPRETATION: Speed of sound measurements fell with age in all infants, but we found no evidence that this measurement could predict biochemical indicators of MBD. We cannot exclude the possibility that this technique could be useful in monitoring the response to interventions designed to improve bone health in this population.

Randomised, double blind trial of oxytocin nasal spray in mothers expressing breast milk for preterm infants.

BACKGROUND: Human milk has considerable short and long term benefits for preterm infants, but mothers may experience difficulties in expressing breast milk for infants too immature or sick to breast feed. Oxytocin has been used to assist breast feeding and milk expression, but few data are available to support this intervention in the neonatal unit setting. AIM: To test the hypothesis that oxytocin nasal spray increases early milk output in mothers expressing milk for preterm infants. METHODS: A randomised, double blind trial of oxytocin nasal spray (100 microl per dose) versus placebo was conducted in mothers delivering infants <35 weeks gestation. Sprays were used before expression of milk using an electric pump up to day 5. MAIN OUTCOME: Total weight of milk expressed while using spray (study powered to detect >1SD difference between groups). SECONDARY OUTCOMES: Pattern of milk production; number of pumping sessions; weight/fat content of milk expressed during a fixed 20 minute period on day 5 ("physiological study"); mother's opinion of expressing and spray assessed by questionnaire. RESULTS: Fifty one mothers were randomised (27 oxytocin, 24 placebo). Total milk production did not differ between groups. Repeated measures analysis of variance suggested significantly (p = 0.001) different patterns of milk production, with initial faster production in the oxytocin group then convergence between groups. Parity did not influence the response to the intervention. No significant differences were seen in milk weight or fat content in the physiological study nor in mothers' opinions of milk expression and treatment. CONCLUSIONS: Despite marginal differences in the pattern of early milk production, the use of oxytocin nasal spray did not significantly improve outcome. Most mothers believed they were receiving the active spray, suggesting a significant placebo effect (supported by limited data from historical controls) and benefits from the extra breast feeding support available during the study.

Predictors of expressed breast milk volume in mothers expressing milk for their preterm infant.

BACKGROUND: An understanding of predictors of breast milk production may enable the provision of better advice and support to mothers with preterm infants who may need to express milk for long periods. OBJECTIVE: To investigate factors predicting the amount of milk expressed by mothers for their preterm infant (1) during the first 10 days and (2) during the infant's whole hospital stay. METHODS: 62 mothers with preterm infants <34 weeks who participated in a randomised trial comparing two breast pumps completed 10-day diaries including weight of milk expressed and questionnaires giving their opinion of the breast pump; 47 mothers provided data on milk expression up to the infant's hospital discharge. RESULTS: Significant predictors of 10-day milk weight in multivariate models were the number of episodes of 'breast feeding' (17 g (95% CI 8 to 26, p=0.001) increase per episode), the use of double versus single pumping (109 (31-186, p=0.007) g/day more) and the number of complete daily records (17 (1-33, p=0.04) g increase/day). Significant multivariate predictors of total milk production were double versus single pumping (491 (55) mL/day vs 266 (44) mL/day), expressing 500 mL/day by day 10 (525 (53) mL/day vs 232 (43) mL/day) and a higher score for breast pump 'comfort' (best=489 (39) mL/day, middle=335 (57) mL/day, worst=311 (78) mL/day). CONCLUSIONS: These results suggest that relatively simple, modifiable factors can favourably impact milk production in the neonatal intensive care unit setting and emphasise the importance of double pumping, early establishment of milk production and design features of the breast pump that promote comfort. TRIAL REGISTRATION NUMBER: NCT00887991.

Dual X-ray absorptiometry (DXA) of the lumbar spine in a clinical paediatric setting: does the method of size-adjustment matter?

UNLABELLED: Dual X-ray absorptiometry (DXA) is increasingly used in a clinical setting to evaluate bone mass in children. Areal Bone Mineral Density (aBMD) measurements are known to be influenced by body size, but there is no consensus on the optimal way to deal with this for individual patients. AIM: To compare parameters of bone mass with varying degrees of size correction and to determine the effect on the categorisation of patients as normal or abnormal. SUBJECTS AND METHODS: Healthy children (n = 78) and 4 groups of patients (n = 194) underwent DXA scans of the lumbar spine (L2-4, GE Lunar Prodigy). Five measures of bone mass were derived, all adjusted for age and sex: aBMD, BMAD (BMC/BA (1.5)), BMCh (BMC/height3), BMCa (BMC adjusted for BA), BMCt (BMC adjusted for BA and height). SD scores were calculated for each parameter for patients using data from healthy controls. RESULTS: Compared to healthy children, all patient groups had significantly reduced BMD SD scores (P < 0.001). Mean BMAD, BMCa and BMCt SD scores were significantly lower in only 2/4 patient groups, whilst BMCh SD scores were low only in one group. BMCt showed no advantage over BMCa. The proportion of patients with SD scores <-2 was 27% for aBMD but between 10-13% for BMAD, BMCh and BMCa. CONCLUSIONS: All size-corrected parameters of bone mass performed similarly and classified significantly fewer patients as abnormal than did aBMD. The use of one of these parameters should reduce the number of patients diagnosed inappropriately with 'low bone mass'. However, without validation against an outcome measure or 'gold standard' of bone density or structure, it is not possible to determine which parameter is most correct.

Body composition in young female eating-disorder patients with severe weight loss and controls: evidence from the four-component model and evaluation of DXA.

BACKGROUND/OBJECTIVES: Whether fat-free mass (FFM) and its components are depleted in eating-disorder (ED) patients is uncertain. Dual energy X-ray absorptiometry (DXA) is widely used to assess body composition in pediatric ED patients; however, its accuracy in underweight populations remains unknown. We aimed (1) to assess body composition of young females with ED involving substantial weight loss, relative to healthy controls using the four-component (4C) model, and (2) to explore the validity of DXA body composition assessment in ED patients. SUBJECTS/METHODS: Body composition of 13 females with ED and 117 controls, aged 10-18 years, was investigated using the 4C model. Accuracy of DXA for estimation of FFM and fat mass (FM) was tested using the approach of Bland and Altman. RESULTS: Adjusting for age, height and pubertal stage, ED patients had significantly lower whole-body FM, FFM, protein mass (PM) and mineral mass (MM) compared with controls. Trunk and limb FM and limb lean soft tissue were significantly lower in ED patients. However, no significant difference in the hydration of FFM was detected. Compared with the 4C model, DXA overestimated FM by 5 ± 36% and underestimated FFM by 1 ± 9% in ED patients. CONCLUSION: Our study confirms that ED patients are depleted not only in FM but also in FFM, PM and MM. DXA has limitations for estimating body composition in individual young female ED patients.

Bone mineralization and turnover in preterm infants at 8-12 years of age: the effect of early diet.

Our previous studies raised two hypotheses: first that suboptimal early nutrition and second that human milk have enhancing effects on long-term bone mineralization. To test these hypotheses experimentally, we measured whole body and regional bone mineral content (BMC) and bone mineral density (BMD), using dual-energy X-ray absorptiometry and single-photon absorptiometry, and bone turnover at 8-12 years in 244 preterm children (128 boys) who participated in a prospective randomized study of diet during the neonatal period. Dietary randomizations studied were: banked human milk (BBM, n = 87) versus preterm formula (PTF, n = 96) as the sole diet or as a supplement to mother's expressed breast milk (EBM); PTF (n = 25) versus term formula (TF, n = 36) as sole diet. Ninety-five term children of the same age were also studied. First, preterm children were shorter and lighter than term children (height SD scores -0.49 (1.1) vs. +0.22 (0.9), weight SD scores -0.41 (1.2) vs. +0.38 (1.0)) and had significantly lower whole-body BMC than their peers; decrements were also evident at some regional sites. These differences disappeared after adjusting for bone area, body size, and pubertal status. Second, children previously randomized to BBM versus PTF or TF versus PTF showed no significant differences in anthropometry, BMC, BMD, or osteocalcin (OC). Third, there was no independent effect of the proportion of EBM on BMC, BMD, or OC and no interaction between randomized diet and the amount of EBM received. Fourth, plasma OC was significantly higher in preterm children than in term children (12.4 vs. 11.0 ng/ml, p < 0.005) and in preterm children who had received a low-nutrient (BBM/TF) as opposed to a high-nutrient diet (PTF) during the neonatal period (12. 9 vs. 11.9 ng/ml, p = 0.03). In conclusion, preterm children are shorter, lighter, and have lower bone mass than their peers at age 8-12 years. The lower BMC is, however, appropriate for the bone and body size achieved. Despite large differences in early mineral intake, early diet does not affect bone mass in preterm children, and fresh human milk has no specific effect. However, poor nutrition during the neonatal period may result in higher bone formation rates during childhood.

Four-component model of body composition in children: density and hydration of fat-free mass and comparison with simpler models.

BACKGROUND: Body composition in children is generally measured by 2-component (2C) models, which are subject to error arising from variation in fat-free mass (FFM) composition. The 4-component (4C) model, which divides body weight into fat, water, mineral, and protein, can overcome these limitations. OBJECTIVE: The aims of our study were to 1) describe 4C model data for children aged 8-12 y; 2) evaluate interindividual variability in the hydration, bone mineral content, and density of FFM; 3) evaluate the success with which 2C models and bedside techniques measure body composition in this age group with use of the 4C model as a reference. DESIGN: Dual-energy X-ray absorptiometry, underwater weighing, deuterium dilution, bioelectrical impedance analysis, and anthropometry were used to determine body composition in 30 children. The contribution of methodologic error to the observed variability in the hydration and density of FFM was evaluated by using propagation of error. RESULTS: Mean (+/-SD) FFM density and hydration were 1.0864+/-0.0074 kg/L and 75.3+/-2.2%, respectively, and were significantly different from adult values (P < 0.02). Relative to the 4C model, deuterium dilution and dual-energy X-ray absorptiometry showed no mean bias for fatness, whereas underwater weighing underestimated fatness (P < 0.025). Fatness determined by using skinfold-thickness and bioelectrical impedance analysis measurements along with published equations showed poor agreement with 4C model data. CONCLUSIONS: Biological variability and methodologic error contribute equally to the variability of FFM composition. Our findings have major implications for bedside prediction methods used for children, traditionally developed in relation to underwater weighing.

Randomized outcome trial of human milk fortification and developmental outcome in preterm infants.

Despite potential benefits, human milk may fail to meet preterm infants' nutrient requirements. We tested the hypothesis that fortified breast milk, fed alone or with preterm formula, would improve neurodevelopment and growth at 18-mo follow-up without adverse short-term clinical or biochemical consequences. Two hundred seventy-five preterm infants from two medical centers (birth weight < 1850 g; mean gestation 29.8 +/- 2.7 wk) whose mothers chose to provide breast milk were randomly assigned to receive for a mean of 39 d a multinutrient fortifier or control supplement containing phosphate and vitamins. Breast milk comprised 47.6% and 46.4% of enteral intake in fortified and control groups, respectively; preterm formula supplements were used when insufficient breast milk was available. Overall, there were no significant growth advantages with fortification; although, when breast milk exceeded 50% of intake, fortification promoted faster weight gain (an advantage of 1.6 g.kg-1.d-1; 95% CI: 0.1, 3.1; P < 0.05). Compared with control infants, the fortified group showed 1) higher plasma urea from week 2 (P = 0.04), 2) higher plasma calcium (mean 2.34 +/- 0.01 compared with 2.27 +/- 0.02 mmol/L; P = 0.003), 3) a greater rise in alkaline phosphatase by week 6 (P = 0.04), 4) more clinical infections (suspected plus proven; 43% compared with 31%, P = 0.04), 5) a nonsignificantly increased incidence of necrotizing enterocolitis (5.8% compared with 2.2%, P = 0.12), and 6) higher white cell and platelet counts. Developmental scores at 18 mo were slightly but not significantly higher in the fortified group. This study confirmed that breast milk fortifiers can improve short-term growth (when breast milk intakes are high); but beneficial effects on long-term development remained unproven. Future research is required to evaluate potential adverse consequences and explore more optimal fortification strategies.

Double-blind, randomized trial of a synthetic triacylglycerol in formula-fed term infants: effects on stool biochemistry, stool characteristics, and bone mineralization.

BACKGROUND: The low sn-2 palmitate content of infant formulas results in formation of fatty acid calcium soaps in the stools and reduced calcium absorption. OBJECTIVE: Our objective was to test the hypotheses that increasing the proportion of sn-2 palmitate in formula for term infants would result in greater skeletal mineral deposition and reduced stool hardness. DESIGN: Healthy term neonates were randomly assigned to receive standard formula (n = 103) or formula containing 50% sn-2 palmitate (high-sn-2 formula; n = 100) for 12 wk. One hundred twenty breast-fed infants were also studied. The main outcome measures were 1) radial (single-photon absorptiometry) and whole-body (dual-energy X-ray absorptiometry) bone mineral content (WBBMC) at 12 wk and 2) stool frequency, volume, and consistency at 6 and 12 wk. Secondary outcome measures included stool fatty acid content. RESULTS: Infants receiving high-sn-2 formula had higher WBBMC (128.1 +/- 9.7 compared with 122.7 +/- 10.1 g, adjusted for size and sex), softer stools at 6 and 12 wk, and a lower proportion of stool soap fatty acids than did infants receiving the control formula. Breast-fed infants had adjusted WBBMC values (128.3 +/- 9.1 g) similar to those of infants fed high-sn-2 formula and significantly higher than those of infants fed the control formula. CONCLUSIONS: Changing the stereoisomeric structure of palmitate in infant formula resulted in higher WBBMC, reduced stool soap fatty acids, and softer stools more like those of breast-fed infants. The greater bone mass measured could be important if it persists beyond the trial period; this merits further investigation.

Catch-up growth in small-for-gestational-age term infants: a randomized trial.

BACKGROUND: Small-for-gestational-age (SGA) term infants are at risk of long-term growth deficits. OBJECTIVE: The objectives were to test the hypothesis that postnatal growth in SGA term infants can be altered by dietary intervention and to examine whether there is a critical window for nutritional programming of the growth trajectory during the first 9 mo postnatally. DESIGN: Healthy term (gestation > or =37 wk) infants with birth weights below the 10th centile were randomly assigned to receive standard term formula (TF; n = 147) or nutrient-enriched formula (EF; n = 152) for the first 9 mo; 175 breast-fed SGA term infants formed a reference group. The main outcome measures were weight, length, and occipitofrontal head circumference (OFC) at 9 and 18 mo. RESULTS: The infants fed the EF showed greater gains in length by 9 (1.1 cm; 95% CI: 0.38, 1.79) and 18 (1.0 cm; 0.25, 1.83) mo and in OFC by 9 (0.5 cm; 0.1, 0.9) and 18 (0.6 cm; 0.2, 1.1) mo than did infants fed the TF; the differences were larger in females. The dietary effects were independent of the pattern of growth retardation. Breast-fed infants showed greater gains in weight and OFC by 18 mo than did infants fed the TF; however, these differences disappeared after adjustment for age, parental size, and birth order. CONCLUSIONS: Linear growth and OFC gains in SGA term infants improve after nutritional intervention during the first 9 mo of life and the effects persist for > or =9 mo beyond the intervention period. Further information on whether catch-up growth is beneficial or detrimental to long-term outcomes is required before public health interventions can be recommended.