Abstract 1505 Poster Session III, Monday, 5/3 (poster 53)

In spite of progress in the management of hyaline membrane disease (HMD) it continues to be a significant cause of infant morbidity and mortality. This study was performed to examine the risk factors, both traditional and intergenerational, for HMD in multiple ethnic groups. A population-based database consisting of hospital records linked to Washington State maternal and infant vital records was developed. Four racial/ethnic groups were studied: Whites, African Americans, Native Americans, and Hispanics. Poisson regression models were used to estimate relative risks of various factors for HMD. Rates for HMD were as follows: Whites, 1.17%, African Americans, 1.93%; Native Americans, 1.28%; Hispanics, 1.02%. Traditional risk factors for HMD were found to be: cesarean section, prematurity, low infant birthweight and prolonged rupture of membranes. Because delivery by cesarean section was such a strong risk factor for HMD, separate analyses were performed for infants delivered vaginally and by cesarean section. Low maternal birthweight (MBW) was associated with increased relative risk (RR) for HMD in Whites [2.60 (95% CI 1.58-4.25)] and African Americans [3.22 (95% CI 1.89-5.47)] for infants born vaginally. The association of low MBW with HMD persisted in African Americans even when multiple risk factors (low infant birthweight, prematurity, maternal smoking, and late prenatal care) were added to the model, RR=2.33 (95% CI 1.10-4.94). The association of low MBW with HMD is probably due in part to the association of low MBW with infant low birthweight and preterm birth. The MBW distribution of African American is displaced downwards compared to other ethnic groups. That, plus the strong association of low MBW with HMD in African Americans, suggests that the improvement of perinatal outcomes in this ethnic group will require improvement of their birthweight distribution on a long-term basis.