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.

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.

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.

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.

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.

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.