HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS REGISTER		Author Keyword(s) Vol Page [Advanced]

This Article Full Text Full Text (PDF) All Versions of this Article: adc.2006.105742v1 92/5/F381    most recent Submit a response Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Citation Map Services Email this link to a friend Similar articles in ADC Online Similar articles in PubMed Add article to my folders Download to citation manager Request Permissions Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Mercy, J Articles by Mughal, M Z Search for Related Content PubMed PubMed Citation Articles by Mercy, J Articles by Mughal, M Z

Relationship of tibial speed of sound and lower limb length to nutrient intake in preterm infants

¹ Department of Neonatal Medicine, St Mary’s Hospital for Women and Children, Manchester, UK
² Department of Medical Statistics, South Manchester University Hospitals Trust, Manchester, UK
³ Department of Paediatric Medicine, St Mary’s Hospital for Women and Children, Manchester, UK

Correspondence to:
Dr M Zulf Mughal, Department of Paediatric Medicine, St Mary’s Hospital for Women & Children, Hathersage Road, Manchester M13 0JH, England; zulf.mughal{at}cmmc.nhs.uk

Background: Metabolic bone disease of prematurity is characterised by impaired postnatal mineralisation of the rapidly growing infant skeleton.

Objective: To longitudinally evaluate postnatal changes in tibial speed of sound (tSOS; which reflects cortical thickness and bone mineral density) and lower limb length (LLL; a measure of tibial growth) in very low birthweight preterm infants receiving contemporary neonatal care.

Methods: tSOS and LLL were measured using a quantitative ultrasound device and an electronic neonatal knemometer, respectively, in the same limb, weekly, for a median period of four weeks (3–16 weeks) in 84 preterm infants (median gestation 26.8 weeks (range 23–35.2 weeks) and median birth weight 869.5 g (range 418–1481 g)).

Results: Initial tSOS and LLL were correlated with gestation (r = 0.42, p<0.001; r = 0.76, p<0.001, respectively) and birth weight (r = 0.23, p = 0.038; r = 0.93, p<0.001, respectively). Postnatally, tSOS decreased (r = –0.15, p = 0.011) whereas LLL increased (r = 0.96, p<0.001) with age. The rate of postnatal change in LLL, but not in tSOS, was positively influenced by intake of calcium (p = 0.03), phosphorus (p = 0.01) and vitamin D (p = 0.03).

Conclusions: The postnatal decline in tSOS, which is probably due to cortical thinning secondary to endocortical bone loss, and increase in LLL provide new insight into the development of long bones in preterm infants.

Keywords: quantitative ultrasound; speed of sound; lower limb length; knemometry; metabolic bone disease of prematurity