Background. Necrotizing enterocolitis is a severe gastrointestinal disease affecting newborn, especially premature, infants. Much about the etiology and patophysiology of NEC is still unclear, but it seems to be multifactorial. Research and clinical studies have come up with many hypotheses about risk factors, some of them contradictory. Objectives. To investigate risk factors for necrotizing enterocolitis (NEC) and if there are any differences between the patients with this disease in 1995-1999 versus 2006-2007.
Methods. A retrospective case-control study of necrotizing enterocolitis in newborn infants born at Rikshospitalet during 1995-1999 and 2006-2007. Controls were matched according to gestational age; two controls per case. The two time-groups were also investigated against each other. Descriptive analyses with Mann-Whitney and Fisher´s exact tests were used, as well as univariate Cox regression model for analyses of the risk factors.
Results. Some of the factors related to feeding showed statistically significant differences between the case- and control-groups. These factors were whether the patient has achieved to be 50% or 100% enterally fed or received breast milk fortifier before symptoms of NEC appeared, compared to the control-group. We also found statistically significant differences between NEC-patients in 1995-1999 versus 2006-2007 regarding factors related to feeding. There was a clear tendency to differences in the postnatal age at which for amino acids and lipids were started, with a much later start-up time for the group from 95-99. There were also significant differences in the maximumdose of amino acids, higher doses being given in the 95-99-group. In addition to the differences in factors related to feeding, we also found statistic significant differences between the group from 95-99 and the group from 06-07 in the number of patients who received antenatal steroids, the number of patients who died and the number of patients who developed IVH, with most patients with these factors in the group from 06-07. The birth weight and the minimum weight also shoved statistically significant differences, with lower weights in the group from 06-07.
Conclusions. The study is too small to allow for unequivocal conclusions, but based on our findings regarding feeding, a reasonable question appears to be whether feeding strategies may be an important factor which can influence the development of necrotizing enterocolitis.