Tactile and Kinesthetic Stimulation (TKS) intervention improves outcomes in weanling rat bone in a neonatal stress model.

OBJECTIVES: Preterm infants are born with low bone mineral. Neonatal stress further impedes bone mineralization. Clinical evidence suggests that tactile and kinesthetic stimulation (TKS) improves bone phenotype and decreases stress response. Clinical and translational studies indicate the IGF-1 axis, responsible for postnatal growth and bone mineralization, is a key player. We hypothesized that TKS would attenuate the negative impact of neonatal stress on bone phenotype and the IGF-1 axis in weanling rats. METHODS: Neonatal stress (STRESS) or TKS (STRESS + 10min TKS) was administered from D6 to D10. Control animals received standard care. Tissue was harvested on D21. Dual energy x-ray absorptiometry (DXA) and bone morphometry were performed and serum osteocalcin, type I procollagen N-terminal propeptide (PINP), tartrate-resistant acid phosphatase (TRAP), and bone and liver mRNA levels of IGF-1, IGF-1 receptor (IGF-1R), and growth hormone receptor (GHR) were measured. RESULTS: Neonatal stress increased bone mineral content (BMC), area (BA), growth plate width, liver IGF-1 mRNA, and serum IGF-1. TKS maintained areal bone mineral density (aBMD) and bone specific IGF-1 and IGF-1R mRNA while STRESS decreased compared to controls. CONCLUSIONS: Neonatal stress results in apparent accelerated growth response. TKS differed from STRESS with improved tibia aBMD and increased bone specific IGF-1 mRNA.

The effect of massage on heart rate variability in preterm infants.

OBJECTIVE: To test the hypothesis that massage would improve autonomic nervous system (ANS) function as measured by heart rate variability (HRV) in preterm infants. STUDY DESIGN: Medically stable, 29- to 32-week preterm infants (17 massage, 20 control) were enrolled in a masked, randomized longitudinal study. Licensed massage therapists provided the massage or control condition twice a day for 4 weeks. Weekly HRV, a measure of ANS development and function, was analyzed using SPSS generalized estimating equations. RESULTS: Infant characteristics were similar between groups. HRV improved in massaged infants but not in the control infants (P<0.05). Massaged males had a greater improvement in HRV than females (P<0.05). HRV in massaged infants was on a trajectory comparable to term-born infants by study completion. CONCLUSION: Massage-improved HRV in a homogeneous sample of hospitalized, medically stable, preterm male infants and may improve infant response to exogenous stressors. We speculate that massage improves ANS function in these infants.

Tactile/kinesthetic stimulation (TKS) increases tibial speed of sound and urinary osteocalcin (U-MidOC and unOC) in premature infants (29-32weeks PMA).

Preterm delivery (<37 weeks post-menstrual age) is associated with suboptimal bone mass. We hypothesized that tactile/kinesthetic stimulation (TKS), a form of infant massage that incorporates kinesthetic movement, would increase bone strength and markers of bone accretion in preterm infants. Preterm, AGA infants (29-32 weeks) were randomly assigned to TKS (N=20) or Control (N=20). Twice daily TKS was provided 6 days per week for 2 weeks. Control infants received the same care without TKS treatment. Treatment was masked to parents, health care providers, and study personnel. Baseline and week two measures were collected for tibial speed of sound (tSOS, m/sec), a surrogate for bone strength, by quantitative ultrasound (Sunlight8000) and urine markers of bone metabolism, pyridinium crosslinks and osteocalcin (U-MidOC and unOC). Infant characteristics at birth and study entry as well as energy/nutrient intake were similar between TKS and Control. TKS intervention attenuated the decrease in tSOS observed in Control infants (p<0.05). Urinary pyridinium crosslinks decreased over time in both TKS and CTL (p<0.005). TKS infants experienced greater increases in urinary osteocalcin (U-MidOC, p<0.001 and unOC, p<0.05). We conclude that TKS improves bone strength in premature infants by attenuating the decrease that normally follows preterm birth. Further, biomarkers of bone metabolism suggest a modification in bone turnover in TKS infants in favor of bone accretion. Taken together, we speculate that TKS improves bone mineralization.

Mechanical-tactile stimulation (MTS) intervention in a neonatal stress model improves long-term outcomes on bone.

OBJECTIVES: Neonatal stress impairs postnatal bone mineralization. Evidence suggests that mechanical tactile stimulation (MTS) in early life decreases stress hormones and improves bone mineralization. Insulin-like growth factor (IGF1) is impacted by stress and essential to bone development. We hypothesized that MTS administered during neonatal stress would improve bone phenotype in later life. We also predicted an increase in bone specific mRNA expression of IGF1 related pathways. METHODS: Neonatal stress (STRESS) and MTS (STRESS+10 min of MTS) were given from D6 to D10 of rat life and tissue was harvested on D60 of life. Dual energy x-ray absorptiometry (DXA), bone morphometry, serum osteocalcin, type I procollagen N-terminal propeptide (PINP), tartrate-resistant acid phosphatase (TRAP), and bone and liver mRNA levels of IGF1, IGF1 receptor (IGF1R), and growth hormone receptor (GHR) were measured. RESULTS: Stress resulted in reduced bone area and bone mineral content (BMC) compared to naive control (CTL). MTS intervention increased BMC and tibial growth plate width compared to STRESS. MTS also resulted in higher osteocalcin, and, in males, lower TRAP (p<0.05). MTS resulted in three-fold, two-fold, and six-fold higher bone specific IGF1, IGF1R, and GHR, respectively (p ≤ 0.001) compared to STRESS. CONCLUSIONS: MTS in early postnatal life improves long-term bone mineralization. IGF1 and related pathways may explain improved BMC.

Massage therapy during early postnatal life promotes greater lean mass and bone growth, mineralization, and strength in juvenile and young adult rats.

The objects of this study were to investigate the effects of massage therapy during early life on postnatal growth, body composition, and skeletal development in juvenile and young adult rats. Massage therapy was performed for 10 minutes daily from D6 to D10 of postnatal life in rat pups (MT, n=24). Body composition, bone area, mineral content, and bone mineral density were measured by dual energy X-ray absorptiometry (DXA); bone strength and intrinsic stiffness on femur shaft were tested by three-point bending; cortical and cancellous bone histomorphometric measurements were performed at D21 and D60. Results were compared to age- and gender-matched controls (C, n=24). D21 body weight, body length, lean mass, and bone area were significantly greater in the MT cohort. Greater bone mineral content was found in male MT rats; bone strength and intrinsic stiffness were greater in D60 MT groups. At D60 MT treatment promoted bone mineralization by increasing trabecular mineral apposition rate in male and endosteal mineral surface in females, and also improved micro-architecture by greater trabeculae width in males and decreasing trabecular separation in females. In summary, massage therapy during early life elicited immediate and prolonged anabolic effects on postnatal growth, lean mass and skeletal developmental in a gender-specific manner in juvenile and young adult rats.

Growth and bone mineralization in children born prematurely.

OBJECTIVE: To study the growth and bone mineralization of children born prematurely. STUDY DESIGN: A cohort of healthy children who were born prematurely with birth weight less than 1.5 kg were compared by weight and height to a national reference. Bone mineral status of preterm infants was compared with children who were born at term gestation. The average follow-up was 7 years. A sample of children who were born prematurely was recalled from an infant nutrition study. Children born at term gestation who had similar body weight for age were recruited from the community. Bone mineral evaluation was conducted in a group of 20 children born prematurely with birth weight less than 1.5 kg and in 15 children born at term gestation. Body weight for age was similar between the groups. All children were born of appropriate size for gestational age at birth. All children had their body weight and height measured. Comparisons for growth assessment status were made with the NHANES III database and published standards. Dietary intakes and food frequency were analyzed. The bone mineral status was measured at two sites, lumbar spine and distal third radius bone. RESULTS: The average age was 7 years, with a range of 5 to 9 years. Compared with the reference population, children who were born prematurely on the average had lower weights, heights and body mass index. Preterm children had a lower lumbar bone mineral content than term children, 12.8+/-3.0 and 14.7+/-2.2 g cm(-1) (P<0.05). The lumbar bone mineral density was lower in the preterm group than in the term group, 0.525+/-0.062 and 0.574+/-0.073 g cm(-2), respectively (P<0.04). Three of the preterm children had a history of fracture whereas none of the term children reported any fractures. CONCLUSION: Children who were born prematurely with birth weights less than 1.5 kg tend to be significantly smaller for age and have lower lumbar spinal bone mineral content and density compared with children born at term gestation.

Maternal-administered physical activity enhances bone mineral acquisition in premature very low birth weight infants.

OBJECTIVE: To determine if physical activity delivered by an infant's mother would be as effective in promoting bone mineral acquisition in preterm very low birth weight (VLBW) infants as the same intervention administered by a trained therapist. PATIENTS AND METHODS: Preterm VLBW infants were randomized to receive daily physical activity administered by the infant's mother (MOM, n=11) or a trained therapist (OT, n=11), or control (n=11). Physical activity consisted of range of motion movements against passive resistance to all extremities for 5 to 10 min daily. All infants were fed mother's milk with fortification to 24 kcal oz(-1). Dual energy x-ray of the forearm bone area (BA, cm(2)), mineral content (BMC, g), and density (BMD, g/cm(2)) and measurement of bone formation (bone-specific alkaline phosphatase, BAP) and resorption (urine pyridinium crosslinks of collagen, Pyd) were obtained at study entry and at 2.0 kg of body weight. RESULT: Forearm BA and BMC gains were greater in MOM and OT infants compared to the control infants despite similar postnatal growth rate and nutrient intake. Serum BAP levels decreased in controls but remained unchanged in MOM and OT infants. Urine Pyd levels were similar at baseline to 2.0 kg for all groups. These findings suggest greater bone growth and mineral acquisition in MOM and OT infants than control infants. CONCLUSION: This study demonstrates that a physical activity program administered by the infant's own mother is as equally effective as therapist-administered physical activity in promoting greater bone growth and mineral acquisition in preterm VLBW infants.

Case-control study of the muscular compartments and osseous strength in neurofibromatosis type 1 using peripheral quantitative computed tomography.

Skeletal anomalies are observed in neurofibromatosis type 1 (NF1), but the pathogenesis is unknown. Given that muscle mass is important in the development of the strength of bone, peripheral quantitative computed tomography (pQCT) was utilized to compare measurements of muscle compartments between NF1 individuals and controls. Forty individuals with NF1 (age 5-18 years) were evaluated. Cross-sectional measurements, at the 66% tibial site, were obtained using pQCT (XCT-2000, Stratec) and variables were compared to controls without NF1 ((age 5-18 years, N=380) using analysis-of-covariance controlling for age, height, Tanner stage, and gender. The NF1 cohort showed decreased total cross-sectional area [p<0.001], decreased muscle plus bone cross-sectional area [p<0.001], decreased muscle cross-sectional area [p<0.001], and decreased Stress Strain Index [p=0.010]. These data indicate that NF1 individuals have decreased muscle cross-sectional area and decreased bone strength than individuals without NF1.

Bone mass and density response to a 12-month trial of calcium and vitamin D supplement in preadolescent girls.

BACKGROUND: Maximal bone acquisition in adolescent girls through dietary and lifestyle practices is advocated to prevent or minimize the development of osteoporosis and its associated complications in later life. Longitudinal investigations of bone acquisition in children and adolescents have utilized areal bone mineral density (BMD, mg/cm(2)) as a measure of bone mass and strength. Peripheral quantitative computed tomography (pQCT), which provides a three-dimensional display of data, separate analyses of bone compartments, and bone mass in terms of volumetric BMD (vBMD, mg/cm(3)), has recently been introduced for clinical use. OBJECTIVE: To assess the impact of a 12-month daily calcium supplement on total and trabecular bone acquisition as measured by pQCT in preadolescent girls. DESIGN: Early adolescent Caucasian girls (aged 12 years, Tanner Stage 2) were enrolled in a randomized trial of daily calcium supplement (TX, 800 mg calcium carbonate and 400 IU vitamin D) or placebo (C). Body weight, height, and distal tibia measurements by pQCT were obtained at enrollment, 6 and 12 months. Pubertal status and physical activity records were assessed at baseline and 12 months. Three-day food intake records were completed every three months. RESULTS: Seventy-one girls completed the 12-month trial (TX=35, C=36). No differences were found for age, weight, height, body mass index, pubertal maturation, or reported physical activity at enrollment or during the study. Average intakes during the study were 1524 mg calcium and 496 IU vitamin D (TX) versus 865 mg calcium and 160 IU vitamin D (C) per day. Baseline total bone values were similar, however, trabecular values were greater in TX girls despite randomization. Percent changes were calculated to adjust for baseline differences. Because of the small cortical thickness at the 10% site (mean values < 1.6 mm), cortical mass and density were not analyzed. The percent changes for trabecular bone mineral content (BMC, mg) and vBMD were significantly greater in TX girls (+4.1% BMC and +1.0% vBMD TX versus -1.6% BMC and -2.0% vBMD C, p<0.006; ANCOVA) after 12 months of supplement. Trabecular bone area (BA, cm(2)) and total bone change, however, did not differ between groups. CONCLUSIONS: Daily calcium and vitamin D supplementation promotes greater trabecular BMC and vBMD acquisition in preadolescent girls. The single site selected for pQCT evaluation in this study did not allow evaluation of the cortical bone compartment. Future studies that utilize the pQCT technique need to incorporate multiple measurement sites to better assess total, cortical, and trabecular bone.

Predictors of bone mass by peripheral quantitative computed tomography in early adolescent girls.

This cross-sectional study used peripheral quantitative computed tomography (pQCT) to evaluate the influences of age, body size, puberty, calcium intake, and physical activity on bone acquisition in healthy early adolescent girls. The pQCT technique provides analyses of volumetric bone mineral density (vBMD) (mg/cm(3)) for total as well as cortical and trabecular bone compartments and bone strength expressed as polar strength strain index (mm(2)). Bone mass of the nondominant distal and midshaft tibia by pQCT and lumbar spine and hip by dual X-ray absorptiometry (DXA) were measured in 84 girls ages 11-14 yr. Pubertal stage, menarche status, anthropometrics, and 3-d food intake and physical activity records were collected. Total and cortical bone mineral content and vBMD measurements by pQCT were significantly related to lumbar spine and femoral neck BMD measurements by DXA. We did not note any significant determinants or predictors for trabecular bone mass. Body weight was the most important predictor and determinant of total and cortical bone density and strength in healthy adolescent girls. Menarche, calcium intake, height, body mass index, and weight-bearing physical activity level age were also identified as minor but significant predictors and determinants of bone density and strength. Bone measurements by the pQCT technique provide information on bone acquisition, architecture, and strength during rapid periods of growth and development. Broader cross-sectional studies using the pQCT technique to evaluate the influence of age, gender, ethnicity, puberty, body size, and lifestyle factors on bone acquisition and strength are needed.

Daily physical activity program increases bone mineralization and growth in preterm very low birth weight infants.

OBJECTIVE: A study of daily physical activity was performed with 32 preterm infants to evaluate changes in body weight and bone mineralization. STUDY DESIGN: Subjects were matched by birth weight and gestational age and randomly assigned to the physical activity (PA; n = 16) or to the control (C; n = 16) program. PA consisted of range of motion against passive resistance to all extremities for 5 to 10 minutes daily. Peripheral dual-energy x-ray of the right forearm (ulna and radius); biomarkers of bone formation (serum type I collagen C-terminal propeptide [PICP]) and resorption (urine pyridinoline cross-links of collagen [Pyd]); serum calcium, phosphate, alkaline phosphatase, parathyroid hormone (PTH), and 1, 25-(OH)(2) vitamin D; and urine levels of calcium, phosphate, and creatinine were obtained. All measurements were made at study entry and at 2.0 kg of body weight. RESULTS: Despite a similar nutrient intake at advised levels for preterm infants, gains in body weight (g) and forearm bone length (cm), bone area (BA; cm(2)), bone mineral content (BMC; mg), and fat-free mass (g) were greater in PA infants. Forearm bone mineral density and fat mass gains did not differ between groups. Serum PICP levels remained constant in PA infants but decreased in C infants suggesting a slower rate of bone formation. Urine Pyd or bone resorption activity was similar between groups. A higher level of serum PTH was observed in PA infants at 2. 0 kg of body weight; however, the change from study entry to completion did not differ between groups. All other serum and urine values were similar and within normal limits. CONCLUSION: A daily PA program promotes greater gains in body weight, forearm length, BA, BMC, and fat-free mass in premature infants.

Postpartum body composition changes in lactating and non-lactating primiparas.

The objective of this study is to evaluate the postpartum body composition changes in lactating versus non-lactating or formula-feeding primiparas during the first 12 wk. Twenty primiparous females (age range 17-35 y) who decided to nurse or formula feed their infant were studied. The non-lactating mothers (n = 6) were younger (21 versus 29 y) and had a lower prepregnancy weight (55 kg versus 63 kg) than the lactating mothers (n = 14). Body weight, height, waist and hip measurements, 3-d dietary and activity records, skin-fold thickness from triceps, suprailiac, midthigh, and midupper arm circumference, and total body composition were evaluated at three time periods (at delivery, at 6 wk, and at 12 wk postpartum). Total body composition for bone mineral, lean, and fat mass was measured by dual energy x-ray absorptiometry. At delivery and 6 wk postpartum, the weights and heights were similar between the two groups. By 12 wk postpartum, the formula-feeding group had a weight loss that was different from delivery, 66 +/- 10 kg to 59 +/- 8 kg, P < 0.03. There was no significant weight change in the lactating group during the study. The weight loss consisted of more lean mass than fat mass. The total body bone mineral content did not differ between the two groups during the study. Both groups had reduction in their waist size from delivery to 12 wk postpartum. But only the non-lactating mothers had reductions in their hip and midthigh measurements. There were no changes between the two groups in the skin-fold measurements. Lactating mothers had a higher total daily calories (1974 +/- 318 versus 1464 +/- 178 calories, P < 0.002) and fat intake (63 +/- 14 versus 47 +/- 9 g, P < 0.02) than the non-lactating mothers. The energy expenditure was similar between both groups. In conclusion, during the first 12 wk postpartum, non-lactating mothers who were younger and weighed less prepregnancy lost body weight and had more waist, hip, and midthigh size reductions compared to lactating mothers.

Eliminating sleep-associated hypoxemia improves growth in infants with bronchopulmonary dysplasia.

OBJECTIVE: Infants with bronchopulmonary dysplasia (BPD) have been previously reported to have a decrease in growth velocity after stopping supplemental oxygen (SO). SO was stopped after a short-term recording (20-30 minutes) of pulse oxygen saturation (Sao2) of 92% or greater in room air. Other studies have documented that Sao2 decreases further during feedings and sleep in infants with BPD. Two questions were asked: (1) whether short-term, awake Sao2 studies would reliably predict prolonged sleep Sao2; and (2) how Sao2 sustained at 88% to 91% vs 92% or greater in room air would impact growth velocity in infants with BPD. METHODOLOGY: Short-term Sao2 studies were prospectively compared with prolonged sleep Sao2 (n = 63) and the growth velocity of infants who had SO discontinued after a prolonged sleep Sao2 recording of 88% to 91% (group 1; n = 14) versus 92% or greater (group 2; n = 34) in room air. RESULTS: Failure to maintain Sao2 at predetermined levels occurred in 18 (29%) of 63 infants during their first prolonged sleep study. There was no correlation between short-term awake Sao2 and prolonged sleep Sao2 recordings (r = .02). Body weight, height, weight for height, and rate of weight gain were similar for all study infants before SO was stopped and remained constant for group 2 infants after SO was stopped. However, group 1 infants had a significant decrease in the rate of weight gain (17.3 +/- 13.1 vs 3.7 +/- 6.1 g/kg per day), and the mean z scores for weight gain and weight for height also decreased significantly for group 1 infants. Energy intake, incidence of acute infection, hematocrit values, and medication use did not differ before or after stopping SO in either group. CONCLUSIONS: This study indicated that short-term, awake Sao2 measurements do not predict prolonged sleep Sao2, and overall, infants with BPD continued a positive growth trend when Sao2, remained greater than 92% during prolonged sleep.

Effect of physical activity on bone mineralization in premature infants.

OBJECTIVE: A 4-week pilot study was done with 26 preterm infants to evaluate whether a physical activity program would result in greater bone mineralization. DESIGN: Subjects were matched by birth weight, gender, and gestational age, and randomly assigned to the physical activity program (group EX; n = 13) or to the control group (group C; n = 13). Physical activity consisted of range of motion with passive resistance to all extremities for 5 to 10 minutes daily. Baseline and 4-week values were determined for both bone mineral analyses and serum levels of calcium, phosphate, alkaline phosphatase, parathyroid hormone, and 25-hydroxy-vitamin D. RESULTS: Despite similar nutrient intake at advised levels for preterm infants, EX infants gained more weight than control subjects (17.8 vs 13.4 gm/kg body weight per day; p = 0.01). A difference in radial bone mass and density change as determined by single-beam photon absorptiometry (+/- 2% error) was found between groups (p = 0.006 by analysis of covariance). Changes in bone width and in bone mineral content and density were enhanced by physical activity. Group EX infants had 12%, 18%, and 34% gains in bone width and in bone mineral density and content, respectively; group C infants had only a 2% gain in bone width and 11% and 14% losses from baseline in bone mineral content and density, respectively, during the 4-week study. Serum biochemical values were similar in the groups except for lower alkaline phosphatase levels in group EX. There was a negative association between bone mineral content and parathyroid hormone values: r = -0.83, p = 0.01. CONCLUSIONS: A physical activity program may increase the effects of adequate nutrition in healthy preterm very low birth weight infants by promoting weight gain and bone mass and by decreasing the risk of osteopenia.

Selenium status of term infants fed human milk or selenite-supplemented soy formula.

Infants fed a soy formula supplemented with selenite had plasma and erythrocyte selenium values lower than those of infants fed human milk. However, plasma and erythrocyte glutathione peroxidase activities were normal, indicating that the physiologic requirement for selenium was being met.

Evaluation of liquid or powdered fortification of human milk on growth and bone mineralization status of preterm infants.

Thirty-five preterm (< 1500 g) infants were fed preterm human milk (PHM) supplemented with either powdered fortifier (PF) or liquid supplement (LS). Bone mineral content (BMC) of the distal third radius was measured by photon absorptiometry. Biochemical indices of nutritional and bone status were obtained every 2 weeks. The initial BMC for both feeding regimens were similar. BMC did not change over the study period for infants fed LS. Infants fed PF had BMC values greater than LS infants at weeks 2 and 4 of study. Only infants fed PF had BMC values that demonstrated a consistent increase. Serum total protein and phosphorus values were greater for PF infants at week 4 than LS infants. Weight, length, occipital-frontal circumference (OFC) gains, serum albumin, alkaline phosphatase, calcium, and vitamin D levels were similar in both groups. We conclude that products used to "enrich" PHM are adequate to meet the growth needs of the preterm infant. However, we found that infants fed the powdered fortified preterm human milk had higher bone mineralization than those fed the liquid supplemented human milk.

An easy and accurate method of estimating newborn birthweight for resuscitation.

Emergency administration of medication based on birthweight is often required in newborn resuscitation. Actual weighing is often delayed because of the emergency situation. Therefore drugs are given according to weight estimates by physicians or nurses. The purposes of this study were to develop a measuring tape using the infant's length and head circumference to determine body weight and to evaluate the performance of the tape measurements to staffs' estimates. Weight, length, and head occipitofrontal circumference (OFC) measurements of 200 newborn infants were collected. By regression analyses, the best log curve for both length and OFC versus weight was determined. From these data, a measuring tape was constructed with the corresponding weights marked for both length and OFC. Forty-five newborn infants with gestational ages of 26 to 40 weeks were studied. Prior to actual weighing, estimates of the birthweights were obtained and recorded from the tape measurements using both the length and OFC and staffs' estimates. For infants less than 2 kg, the average percent error was less by the tape length (1.2%) and OFC (0.7%) compared with staffs' estimates (-7.2%). The tape was also useful in estimating weights of small for gestational age infants. The tape OFC (7.8% error) was more accurate than staffs' estimates (26% error) in these growth-retarded infants. The clinical precision of the tape was 3% with an intrameasurer variability of 5%. We conclude that estimating the birthweight in infants using our tape method is a practical and more accurate way than staff estimates, especially for low birthweight and small for gestational age infants.

Selenium status of preterm infants fed human milk, preterm formula, or selenium-supplemented preterm formula.

The selenium status of 46 orally fed vitamin E-sufficient preterm infants (birth weight less than 1700 gm) was studied longitudinally for 3 weeks to determine the efficacy of selenium supplementation. Infants were fed either human milk (n = 21; 24 ng selenium/ml), preterm formula (n = 13; 7.8 ng selenium/ml), or preterm formula supplemented with sodium selenite (n = 12; 34.8 ng selenium/ml). Plasma and erythrocyte selenium and glutathione peroxidase activity and urinary and dietary selenium content were evaluated on study day 1 (day enteral feeds reached 100 kcal/kg/day) and weekly for 3 weeks. Throughout the study, selenium intakes of infants fed preterm formula plus sodium selenite were greater than those of infants fed human milk, which were greater than those of infants fed preterm formula (p less than 0.001). After 3 weeks no differences were observed among groups for plasma or erythrocyte selenium or glutathione peroxidase. Plasma selenium and glutathione peroxidase values within all groups were low compared with those reported for term infants fed human milk. Whereas urinary selenium levels of infants fed preterm formula plus sodium selenite were greater than those of infants fed preterm formula at weeks 1 and 2 (p less than 0.01), infants fed human milk and preterm formula had lower levels at week 3 than on study day 1 (p less than 0.05). We conclude that blood selenium measurements typically used to monitor selenium status do not reflect dietary selenium intakes of orally fed preterm infants.

Nutritional support of very-low-birth-weight infants requiring prolonged assisted ventilation.

We studied the influence of nutritional support on weight loss and time to regain birth weight (BW) (less than 1500 g) in infants requiring prolonged assisted ventilation. A total of 134 infants admitted between 1980 and 1982 were reviewed. Birth weight, gestational age, lowest recorded daily weight and percentage of loss, days to recover BW, energy intake, and nutrient source during the BW-recovery period were determined. A decrease in weight loss (13% to 10%) and in mean (+/- SD) recovery time (20.9 +/- 7.3 days to 13.8 +/- 6.4 days) in very-low-birth-weight, critically ill infants was noted. The use of parenteral feeding routes increased, as well as tolerance of initial enteral feedings following parenteral support. We attribute the decreased convalescence period for BW recovery to improved nutrition secondary to the increased use and earlier initiation of parenteral nutrition.