Hypercalciuria in ex-preterm children, aged 7-8 years.
In a previous study, 8 of 28 ex-preterm infants, aged 4-5 years, had increased urinary calcium excretion. The aim of this study was to confirm this finding and to determine if raised urinary calcium excretion is associated with reduced bone mineralisation. Forty-six ex-preterm children, aged 7-9 years, and 40 age- and sex-matched controls were recruited. The calcium excretion measured from 3 separate 24-h urine collections was recorded and a dietary assessment made from a diary record. Data were retrieved from the neonatal case notes and included aminoglycoside usage. Dual energy X-ray absorptiometry was used to measure bone mineral content and bone mineral density (BMD) in all children. The mean maximum 24-h urinary calcium was significantly higher in the preterm group than the term group (P=0.01). Increased calcium excretion was associated with raised neonatal aminoglycoside levels (P=0.0013). Height standard deviation score and hip BMD were significantly lower in the 21 preterm children with a 24-h urinary calcium above 4 mg/kg per day than term controls (P=0.04 and P=0.004, respectively). Urinary calcium excretion had a negative relationship with hip BMD in the preterm group (P=0.004). This difference in BMD was not observed in the 25 preterm children with normocalciuria. In the 10 preterm girls with hypercalciuria, hip BMD was lower than in control females (P=0.01). This difference in hip BMD between the 11 preterm boys with hypercalciuria and term boys was not significant (P=0.05). In conclusion, preterm children are shorter and have a lower hip BMD than those with normocalciuria. Further prospective studies are required to assess this risk and its influence on subsequent impaired bone mineralisation.
Jones
C A
CA
Institute of Child Health, Alder Hey, Liverpool, UK. CAJones@doctors.org.uk
Bowden
L S
LS
Watling
R
R
Ryan
S W
SW
Judd
B A
BA
D000886:Anthropometry; D015519:Bone Density; D002118:Calcium / Q000652:urine*; D002648:Child; D002940:Circadian Rhythm; D004032:Diet; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D007234:Infant, Premature / Q000378:metabolism*; D008297:Male; D012727:Sex Characteristics
D002118:Calcium