RICKETS IN VERY-LOW-BIRTH-WEIGHT INFANTS BORN AT BARAGWANATH-HOSPITAL

Disturbed mineral and bone metabolism has been reported to occur frequ ently in very-low-birthweight infants fed breast-milk during the first 3 months of life. This study was designed to assess the prevalence of disturbed mineral homeostasis in a breast-milk-fed very-low-birth-wei ght population at Baragwanath Hospital and to determine whether the ad dition of a preterm infant formula to the feeds would reduce this prev alence and increase the rate of weight gain. Fifty-three neonates weig hing less than 1 200 g at birth were monitored for weight gain, growth and biochemical and radiological evidence of metabolic bone disease a t 2-weekly intervals during hospitalisation and for 18 weeks after dis charge. The infants were randomised at 2 weeks of age to receive eithe r breast-milk only, or a combination of breast-milk and a premature fo rmula containing 550 mg calcium and 300 mg phosphorus. All infants rec eived 800 IU vitamin D daily from day 14. Weight gain and growth were similar in both groups. Calcium and phosphorus intakes were higher in the mixed feeding group, but did not affect serum mineral levels. Radi ological rickets was uncommon in both groups although periosteal react ions and osteopenia occurred frequently and with similar prevalences. Vitamin D deficiency was not found to be a problem. In conclusion, ove rt rickets is not a major problem in very-low-birth-weight infants bor n at Baragwanath Hospital, although biochemical abnormalities occur fr equently. Feeding with breast-milk and a premature infant formula in e qual proportions (as opposed to breast-milk only) does not appear to h ave any effect on weight gain and growth in very-low-birth-weight infa nts but does partially prevent the pathological rise in alkaline phosp hatase levels. It is therefore recommended that breast-feeding of very -low-birthweight infants be encouraged, provided they are monitored re gularly.