Effect of parenteral calcium and phosphorus therapy on mineral retention and bone mineral content in very low birth weight infants.
OBJECTIVE
If calcium and phosphorus are administered to very low birth weight infants in amounts larger than those currently used in standard parenteral nutrition solutions, apparent retention of calcium and phosphorus (intake minus urinary excretion) will increase and bone mineralization will improve.


METHODS
Randomized, controlled, double-blind trial.


METHODS
Neonatal intensive care unit.


METHODS
Twenty-four very low birth weight infants (< 1.2 kg) expected to receive parenteral nutrition exclusively for approximately 3 weeks beginning 3 days after birth.


METHODS
Infants received parenteral nutrition solutions, either the standard mixture containing 1.25 mmol calcium and 1.5 mmol phosphorus per deciliter (group STAND: n = 12, birth weight 921 +/- 171 gm, gestational age 27 +/- 2 weeks (mean +/- SD)) or 1.7 mmol calcium and 2.0 mmol phosphorus per deciliter (group HIGH: n = 12, 857 +/- 180 gm, 27 +/- 2 weeks).


METHODS
Intake, urinary excretion, and apparent retention of calcium, phosphorus, and magnesium every 3 days during parenteral nutrition therapy. Serum indexes of mineral status twice during therapy. Bone mineral content of the distal segment of the left radius at 1, 4, 8, and 26 weeks.


RESULTS
Apparent calcium retention (1.2 +/- 0.2 vs 1.6 +/- 0.2 mmol.kg-1.d-1) and phosphorus retention (1.4 +/- 0.2 vs 1.8 +/- 0.4 mmol.kg-1.d-1) differed significantly (p < 0.01) between groups STAND and HIGH, respectively; neither changed with the duration of parenteral nutrition therapy. Serum calcium, magnesium, parathyroid hormone, 25-hydroxyvitamin D, and osteocalcin concentrations were similar in both groups. Serum phosphorus concentration was significantly higher in group HIGH than in group STAND (p = 0.025). The absolute bone mineral content and the rate of increase in bone mineral content between 1 and 4, 1 and 8, and 1 and 26 weeks were significantly greater in group HIGH than in group STAND.


CONCLUSIONS
Increased parenteral intakes of calcium and phosphorus resulted in greater retention of these minerals during parenteral nutrition therapy and in greater bone mineral content after therapy.
Children's Nutrition Research Center, Houston, Texas 77030.
L L
LL
Prestridge
R J
RJ
Schanler
R J
RJ
Shulman
P A
PA
Burns
L L
LL
Laine
D015519:Bone Density; D001851:Bone Diseases, Metabolic / Q000503:physiopathology / Q000517:prevention & control*; D002113:Calcification, Physiologic; D002118:Calcium / Q000627:therapeutic use* / Q000652:urine; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D007230:Infant, Low Birth Weight / Q000502:physiology* / Q000652:urine; D007231:Infant, Newborn; D007235:Infant, Premature, Diseases / Q000503:physiopathology / Q000517:prevention & control*; D008297:Male; D010288:Parenteral Nutrition; D010758:Phosphorus / Q000627:therapeutic use* / Q000652:urine
D010758:Phosphorus; D002118:Calcium