Effect of ethnicity on mortality of very low birthweight infants in Israel

Background: Multiple demographic, genetic, and environmental factors differ between Muslim and Jewish infants in Israel. Objective: To evaluate whether, after adjustment for perinatal factors associated with mortality, excess mortality occurs in very low birthweight (VLBW) Muslim compared with Jewish infants. Design: The Israel National VLBW infant database includes data on 99% of all VLBW births in Israel. The study population comprised 5015 Jewish and 1549 Muslim VLBW infants of more than 23 weeks gestation, born between 1995 and 1999. The Mantel-Haenszel test was used for stratified analysis and logistic regression analysis to assess the effect of ethnic origin on mortality. Results: The death rate was significantly higher among Muslim infants (22.7% v 17.2%; crude odds ratio 1.42; 95% confidence interval 1.24 to 1.63). Excess mortality in Muslims occurred mainly in the 32-33 week (8.0% v 2.8%) and >33 week (14.7% v4.7%) gestational age groups, and in birthweight groups of 1000-1249 g (17.6% v 9.3%) and 1250-1500 g (9.1% v 3.6%). In VLBW infants without congenital malformations, there was a significantly higher risk of mortality among Muslim infants (odds ratio 1.28; 95% confidence interval 1.04 to 1.57) compared with Jewish infants, after adjustment for gestational age, birth weight, small for gestational age, prenatal care, prenatal steroid treatment, plurality, mode of delivery, and Apgar score. Conclusions: Excess mortality was present among Muslim VLBW infants without congenital malformations. Perinatal factors associated with increased risk of mortality were more prevalent in the Muslim VLBW population. The pattern of disparities suggests inadequate access to, or utilisation of, effective perinatal technology in the Muslim population in Israel.