50 Chapter 3 committee of the VU University Medical Center (approval number 2014.491) and was conducted according to the good clinical practice guidelines and in line with the Declaration of Helsinki. The study was registered at the Dutch Trial Register.12 Measures of endocrine parameters Blood was drawn every other week up to 36 weeks postmenstrual age (PMA) for the measurement of IGF-I and IGFBP-3. Analyses of IGF-I were conducted using chemiluminescence immunoassays (LIAISON®, DiaSorin, Italy) with an intra-assay percent coefficient of variation (%CV) of 8% and an inter-assay %CV of 7%. IGFBP-3 was analyzed with a sandwich ELISA (DRG Instruments GmbH, Germany) with an intra-assay %CV of 5% and an inter-assay %CV of 13%. Morbidities BPD was defined as the need for supplemental oxygen at 36 weeks PMA. Grade 1 BPD was defined as respiratory support through a nasal cannula with a flow of 2L/ minute or less, grade 2 as a flow of 2L/minute or more through a nasal cannula or noninvasive positive airway pressure, grade 3 as invasivemechanical ventilation.13 In addition data on the following comorbidities was collected (see web appendices for definitions): necrotizing enterocolitis (NEC), late-onset sepsis (LOS), intraventricular hemorrhage (IVH), ROP, post hemorrhagic ventricle dilatation (PHVD), infant respiratory distress syndrome (IRDS) and patent ductus arteriosus (PDA). Nutrition Nutrition was initially provided through total parenteral nutrition and minimal enteral feeding.14 Within seven to ten days, 160 ml per kg per day human milk was scheduled to be given fortified with breast milk fortifier. Either own mother’s milk or pasteurized donor humanmilk was given. Donor humanmilk underwent Holder pasteurization (heated at 62.0°C to 62.5°C for 30 minutes, followed by fast cooling to under 4°C).15 If necessary, due to poor growth, up to 2% Nenatal Human Milk Protein Fortifier (Nutricia, Wageningen, The Netherlands) or fat emulsion Calogen (Nutricia, Wageningen, The Netherlands), was added to the fortified human milk. If own mother’s milk was not available, donor human milk was supplied up to 32 weeks PMA, followed by preterm starters formula till discharge home. If parents declined the use of donor human milk, infants were fed preterm starters formula from birth. Data was obtained from hospital records to calculate the daily macronutrient intake based on the reference values for human milk. (table 1) Macronutrient intake, type of enteral nutrition, and parenteral nutrition were assessed as potential confounders. Type of enteral nutrition was defined as predominant own mother’s milk if at least 60% of the enteral intake consisted of own mother’s milk. Likewise predominant donor human milk and predominant formula feeding were defined
RkJQdWJsaXNoZXIy MTk4NDMw