HYPOTHESIS We hypothesize that former ELBW infants, compared to controls following term birth, will be associated with changes in the macro- and microcirculation of the cardiovascular-renal system already in young children over and beyond what is currently known. These changes - even if subtle - are probably forerunners of cardiovascular-renal complications in adulthood. In addition, confounders (e.g. neonatal nutrition, neonatal treatment) documented in the early life may identify new approaches for early prevention.