Objectives: To identify risk factors associated with necrotizing enterocoliti (NEC) in preterm infants and to evaluate the incidence and mortality rate of NEC.

Design and methods: A five years retrospective matched case-control study (matched one-to-one by birthweight + 125 grams) was conducted on preterm infants admitted to the Neonatal Intensive Care Unit (NICU) in Hatyai Hospital between October 1, 2002 to September 30, 2007.

Results: The incidence of NEC was 2.8 per 1,000 livebirths, and the mortality rate was 27.3 percent. Multivariate analysis indicated that the statistically significant risk factors of NEC were intake of full strength formula before diagnosis

of NEC [adjusted odds ratio (adjusted OR) = 6.9, 95% confidence interval (95% CI) = 2.6-17.9], intravenous lipid (adjusted OR = 2.3, 95% CI = 1.3-3.8), patent ductus arteriosus treated with indomethacin (adjusted OR = 3.9, 95% CI = 1.6-

9.6), exchange transfusion (adjusted OR = 5, 95% CI = 1.6-15.8) and umbilical artery catheterizatio (adjusted OR = 3.9, 95% CI = 1.6-9.9). Among all fed pairs, early and trophic enteral nutrition tended to decrease NEC but the difference was not statistically significant.

Conclusion: Intake of full strength formula, intravenous lipid and bowel ischemic could be multifactorial etiologies of NEC.