Variation in use of corticosteroids among infants < or = 1,500 grams across hospitals in three states.

We identified factors associated with no antenatal corticosteroid treatment among 1,369 women who delivered infants < or = 1,500 g and < 34 weeks gestation, 1991-1993. At four hospitals, infants weighing 500-1,500 g were enrolled. Information regarding corticosteroid use, maternal characteristics, and perinatal events were obtained. Factors associated with no corticosteroid treatment were examined in unadjusted and adjusted logistic regression models. Overall, 693 (50.6%) women did not receive corticosteroids. Two hospitals had higher rates of no corticosteroid usage (89% and 75%) as compared with the other two (32% and 50%). Black, Hispanic, and poor women were more likely to receive care at the hospitals where the rates of corticosteroid utilization were lower. Factors in the multivariate model included: < 1 or 1 day of hospitalization, vs. delivery on > or = 2 days of hospitalization (21.4: 14.5, 97.2; 4.7: 3.2, 6.9); gestational age < 26 weeks (2.7: 1.8, 4.1) or > 28 weeks (1.8: 1.3, 2.6) vs. 26-28 weeks; < 12 hours of labor vs. > 12 hours (1.7: 1.2, 2.4); delivering at hospital 2, 3, 4 vs. hospital 1 (1.6: 1.1, 2.5; 24.3: 13.6, 43.4; 10.2: 6.8, 15.3). We conclude that variations in hospital practice limit widespread use of this important antenatal treatment.

Persistent pulmonary hypertension of the newborn and smoking and aspirin and nonsteroidal antiinflammatory drug consumption during pregnancy.

OBJECTIVE: Prenatal causation of persistent pulmonary hypertension of the newborn (PPHB) is suggested by a specific pattern of pulmonary vascular remodeling observed immediately after birth in some infants with fatal PPHN. The goal of this study was to determine whether PPHN is associated with fetal exposure to: (1) tobacco and marijuana smoking (ie, contributors to fetal hypoxemia), (2) consumption of aspirin and other nonsteroidal antiinflammatory drugs (ie, inhibitors of prostaglandin synthesis), and (3) cocaine use (ie, a contributor to vasospasm). DESIGN: Case-control interview study. SETTING: Two Harvard-affiliated newborn intensive care units. PARTICIPANTS: Mothers of case infants who had PPHN or who met criteria for the referent group. INTERVENTIONS: During July 1985 through April 1989, we interviewed mothers of 103 infants with PPHN and 298 control infants. Because of potential selection bias that might result from recruiting only inborn control infants even though two-thirds of cases were outborn, separate analyses compared the 103 total and 35 inborn infants with PPHN with the 298 inborn control infants. Multivariate analyses were used to adjust for potential confounding factors, including maternal education and Medicaid health insurance (ie, two markers of socioeconomic status), other antenatal factors found to be associated with PPHN (ie, maternal urinary tract infection and diabetes mellitus), and the infant's sex. MAIN OUTCOME MEASURES: Self-reported use or consumption of tobacco, marijuana, cocaine, aspirin, and other nonsteroidal antiinflammatory drugs during pregnancy. RESULTS: The adjusted odds ratios (and 95% confidence intervals) for maternal pregnancy exposures to the factors of principal interest among the total study population were: aspirin, 4.9 (1.6-15.3); and nonsteroidal antiinflammatory drugs, 6.2 (1.8-21.8); for the inborn group they were aspirin, 9.6 (2.4-39.0); and nonsteroidal antiinflammatory drugs, 17.5 (4.3-71.6). Although the association between tobacco smoking during pregnancy and PPHN was elevated in univariate analyses, with odds ratios (and 95% confidence intervals) of 2.0 (1.2-3.4) and 1.3 (0.6-3.3) for total and inborn populations, respectively, the relationship was not significant after adjustment for all other factors in the final logistic regression model. Acknowledged illicit drug use was too infrequent (3.2%) to evaluate. CONCLUSION: Maternal consumption of nonsteroidal antiinflammatory drugs and aspirin during pregnancy or the reasons these drugs were ingested seem to contribute to an increased risk of PPHN.

Lead, IQ and social class.

Social class (SC) conveys information about a child's potential lead exposure (PB) as well as other, independent determinants of cognition (IQ). Thus, depending on the way in which SC is handled in statistical analyses, the PB-IQ association may be either 'overadjusted' or 'underadjusted' for SC. Two assumptions that underlie the inclusion of SC in correlation/regression analyses of the PB-IQ relationship are: 1) SC is an interval scale and 2) the PB-IQ relationship is homogeneous in all social strata. Simulation analyses are presented to illustrate the impact that different values of the bivariate correlations PB-SC, IQ-SC, and PB-IQ have on the estimate of the PB-IQ adjusted for SC. Alternative approaches to addressing these issues are discussed.

Low-level lead exposure, social class, and infant development.

A prospective cohort study was conducted to assess the association between early development and low-level prenatal and postnatal lead exposure. Infants' performance between 6 and 24 months on the Mental Development Index of the Bayley Scales of Infant Development declined with increasing concentration of lead in blood, but the decline varied with children's age at exposure, level of exposure, and socioeconomic status. Within the second year of life, the performance of children in lower socioeconomic strata was adversely affected at lower levels of prenatal exposure (blood lead levels of 6 to 7 micrograms/dl) than was the performance of children in higher socioeconomic strata. However, even the performance of these advantaged infants was lower when cord blood lead level exceeded 10 micrograms/dl, well below the figure currently regarded as the maximum permissable level for young children. Exploratory analyses suggested that early postnatal blood lead levels between 10 and 25 micrograms/dl were also associated with lower Mental Development Index scores, but only among children in lower socioeconomic strata.

The prophylactic clinical trial as a epidemiologic resource.

We encourage investigators to use data collected in a clinical trial of a prophylactic agent or procedure to study the epidemiology of the disease or event the prophylactic was meant to prevent. Making additional use of previously collected data is economically attractive. Problems can arise, however, if the sample is not representative of the universe of all people at risk of the disorder, the data set is not adequate to the task, or the prophylactic and/or its correlates influence the risk of the disorder. Investigators should consider modifying data collection procedures in future prophylactic trials so that they are suitable for an epidemiologic study. They and readers of their reports, however, are advised to be cautious in drawing inferences from epidemiologic studies extracted from prophylactic trials.

Correlates of low-level lead exposure in urban children at 2 years of age.

The blood lead levels of a large number of US preschool children approach the value regarded as the upper limit of normal. To reduce the number of children whose levels increase into the range thought to be toxic, the antecedents and correlates of levels in the 0- to 25-micrograms/dL range must be identified. In a large longitudinal study of middle and upper-middle class children living in metropolitan Boston, we evaluated how well five sets of variables predicted children's blood lead levels at 2 years of age: environmental lead sources, mouthing activity, home environment/care giving, prior developmental status, and sociodemographic characteristics. A series of bivariate and multivariate analyses indicated that only environmental lead sources and, to a lesser extent, mouthing activity accounted for significant portions of the variance in blood lead levels. Environmental lead sources were not significantly related to the home environment/care-giving variables or to sociodemographic characteristics. The most promising approach for achieving community-wide reductions in children's blood lead levels is reduction in the amount of lead in the proximate environment.

Posttraumatic seizures: an assessment of the epidemiologic literature.

Confusion about the risk of seizures following head trauma might in part reflect methodologic limitations of reported studies. This epidemiologic review emphasizes four methodologic issues: selection of cases, selection of controls, definition and ascertain of seizures, and definition, of seizures, and definition, classification, and ascertainment of trauma. Although the focus of this review is a set of reports of civilian injuries, the relevance of war studies to civilian injuries is also discussed.