173 General discussion 8 (every other week). This led to relatively small sample sizes and thus limited statistical power. With techniques which use smaller sample volumes, such as IGF-I measurements in dried blood spots(7), future studies could increase IGF-I sampling frequency and increase the statistical power. In the future sufficiently powered interventional studies are required to investigate whether growth and body composition can be optimized further with nutritional interventions. In light of the growing availability of donor human milk and exclusive human milk diets it would be valuable to assess whether humanmilk fortification should be adapted to IGF-I levels. Currently, in most practices human milk for preterm infants is fortified with a standard amount of protein. However, Rochow and colleagues showed that analysing human milk samples and individually adjusting the macronutrient content to meet recommended intakes, improves growth.(8) On the contrary, in a study by Agakidou et al. this so-called protein-targeting fortification of human milk, compared to fixed-fortification, led to lower daily protein and energy intake. In their study population these lower macronutrient intakes were associated with transiently lower IGF-I levels. (9) It would be insightful to investigate whether a more sustainable effect on IGF-I and growth could be obtained if IGF-I levels were considered in determining the amount of human milk fortification. Speculatively, protein fortification could be reduced, once IGF-I levels increase and pass the theoretical threshold value of IGF-I between 30 and 32 weeks postmenstrual age. Moreover, the effect of donor human milk on growth, body composition and comorbidities needs to be explored further. An exclusive human milk diet is associated with improved health outcomes in preterm infants.(10) Studies show that, compared to preterm formula, donor human milk reduces the risk of necrotizing enterocolitis.(11) Nevertheless, several controlled trials have failed to show that supplementation of donor human milk compared to preterm formula improves short term outcomes or mortality. (11-13) During hospitalization predominant donor human milk feeding has been associated with less weight gain and linear growth compared to preterm formula feeding (11, 14, 15) and also compared to own mother’s milk feeding (15). This is in line with our findings described in chapter 3, suggesting donor human milk use is associated with lower IGF-I levels. Speculatively, this could be associated with less catch-up growth and improved cardiometabolic outcomes, but poorer neurodevelopmental outcomes. However, on the long term no differences in growth have been reported (11, 16) and 5 year olds born very low birth weight showed comparable body composition when donor human milk feeding was compared to formula feeding. (16) Furthermore, despite lower protein content in donor human milk, donor human milk has not been shown to worsen neurodevelopmental outcome when compared to formula feeding. (11) Nevertheless, while own mother’s milk improves neurodevelopmental outcome when compared to formula feeding, donor human milk has not been shown to have that same beneficial effect when compared to formula feeding. (17) It would be valuable to investigate how donor human milk could be optimized further to retain the beneficial effects of own mother’s milk.
RkJQdWJsaXNoZXIy MTk4NDMw