Bibian van der Voorn

30 CHAPTER 2 as well as on short- and long-term morbidity and mortality after very preterm birth has been described 7-9 . To elucidate some potential mechanisms clarifying these associations, we assessed in Chapter 7 on 19-year-old very preterm born subjects from the Project On Preterm and Small-for-gestational-age (POPS) birth cohort, whether antenatal glucocorticoid treatment and a genetic predisposition that influences sensitivity to glucocorticoids, were associated with neurocognitive impairments. In Chapter 8 we assessed HPA axis development from term age up till age 8 years by analyzing unstimulated cortisol levels in association with birth weight and postnatal growth, among children that were born very preterm and/or with a very low birth weight, i.e., <1500g (VLBW), who participated in the ‘Study Towards the Effect of Postdischarge nutrition’ (STEP). In Chapter 9 we conducted a systematic review and meta-analysis to assess whether sex-specific differences in unstimulated HPA axis activity are already present in early life in healthy children. In Chapter 10 we conducted a systematic review to assess whether sex-specific differences in early life in healthy children are also found in HPA axis reactivity, i.e., the response to either exogenous (e.g., pharmacological, physical or social) or endogenous stimuli (e.g., the cortisol awakening response), or as a result of diurnal rhythmicity.