The impact of changes in preterm birth among twins on stillbirth and infant mortality in the United States.

OBJECTIVE: To examine trends for preterm births, stillbirths, neonatal and infant deaths in twin births by gestational age and birth weight categories, as well as trends in induction of labor and cesarean delivery during 1995-2006. STUDY DESIGN: A trend analysis was performed on data derived from the National Centers for Health Statistics' Vital Statistics Data files (1995-2006). The primary outcomes examined were preterm birth, stillbirth, neonatal and infant mortality. RESULT: During the study period, rates of labor induction among twins decreased by 8% and rates of cesarean delivery increased by 35%. Concurrently, the preterm birth rate increased by 13% from 54% in 1995-96 to 61% in 2005-06. The overall stillbirth rate, and neonatal and infant death rates decreased during the same period by 21% (95% confidence interval (CI): 18-25%), 13% (95% CI: 9-16%) and 12% (95% CI: 8-15%), respectively. There were significant reductions in neonatal death rates related to respiratory distress syndrome (RDS; 48%, 95% CI: 41-54%) and congenital anomalies (25%, 95% CI: 16-33%) during the study period. Reductions in post-neonatal infant mortality were mainly in RDS (88%) and sudden infant death syndrome (26%). Mortality rates among infants born by either induction of labor or cesarean delivery fell during the study period and remained much lower than the overall infant mortality rate. CONCLUSION: The findings of this study suggest that during 1995-2006 there was an increase in preterm birth rates and a decrease in labor inductions with a sharp decline in stillbirth, neonatal and infant mortality rates.

Initial metformin or sulphonylurea exposure and cancer occurrence among patients with type 2 diabetes mellitus.

AIM: This was a retrospective cohort study of type 2 diabetes patients, to evaluate the association between initial metformin or sulphonylurea treatment and cancer incidence. METHODS: Patients identified in the UK Clinical Practice Research Datalink (CPRD), previously General Practice Research Database, during 1995-2008 who were initially stabilized on OHA monotherapy, including metformin, sulphonylurea, thiazolidinediones (TZDs) or meglitinides, were included in the cohort. New diagnoses of cancer, including malignant solid tumours and haematological malignancies, occurring during the follow-up were identified from the cohort. Age-standardized incidence rates were estimated and compared between metformin and sulphonylurea exposure groups. RESULTS: The age standardized incidences of cancer were 7.5 and 8.5 per 1000 person-years for the metformin and sulphonylurea exposure groups, respectively. After adjusting for potential confounders, the hazard ratios (HR) for malignant solid tumours and haematological malignancies were 1.06 (95% CI: 0.98, 1.15) and 0.98 (95% CI: 0.67, 1.43) for sulphonylurea group as compared to the metformin group, respectively. For individual cancers, the HRs were 1.17 (95% CI: 0.95, 1.44), 1.04 (95% CI: 0.83, 1.31) and 0.88 (95% CI: 0.71, 1.11) for colorectal cancer, breast cancer and prostate cancer, respectively. CONCLUSION: This study provides evidence that cancer incidence in the first few years after starting metformin or sulphonylurea therapy in type 2 diabetes patients is not much affected by choice of hypoglycaemic drug class.

Two-year glycaemic control and healthcare expenditures following initiation of insulin glargine versus neutral protamine Hagedorn insulin in type 2 diabetes.

AIMS: To compare 2-year glycaemic control, hypoglycaemia and healthcare expenditures following insulin glargine (glargine, n = 2105) or neutral protamine Hagedorn (NPH) insulin (NPH, n = 734) initiation in patients with type 2 diabetes (T2D). METHODS: Retrospective cohort study using an integrated US health insurance administrative database was conducted. Individuals with a diabetes diagnostic claim and initiated basal insulin therapy with glargine or NPH from 2001 to 2005 dispensed at least one oral antidiabetic drug prescription during 6 months prior to basal insulin initiation and enrolled in the same health insurance plan from 6 months before to 12 months or more after insulin initiation were identified. Repeated measures mixed-effects models evaluated glycaemic and financial outcomes to account for factors potentially contributing to selection of insulin therapy, that is, age, gender, baseline HbA1c level, health expenditures, co-morbidities, healthcare utilization, pharmacy co-payment and follow-up antidiabetic medications. RESULTS: Adjusted mean HbA1c value in the first year following insulin initiation was significantly lower for glargine versus NPH initiators (Δ = -0.43, p = 0.006); this difference diminished in the second year (Δ = -0.16, p = 0.375). First-year adjusted quarterly hypoglycaemia incidence rates were lower for glargine (2.1%) versus NPH (2.4%) (p = 0.02) as was the second-year quarterly rate (1.8 vs. 2.2%; p = 0.01). Both the first- and second-year adjusted total healthcare expenditures were lower in the glargine versus NPH group (year 1: $18,720 vs. $19,996, p = 0.005; year 2: $15,008 vs. $17,336; p < 0.001). CONCLUSIONS: Glargine therapy may be an effective long-term option for improving glycaemic control, with lower rates of hypoglycaemia and healthcare costs in patients with T2D.

Ambient air pollutant concentrations during pregnancy and the risk of fetal growth restriction.

BACKGROUND: Previous studies of air pollution and birth outcomes have not evaluated whether complicated pregnancies might be susceptible to the adverse effects of air pollution. It was hypothesised that trimester mean pollutant concentrations could be associated with fetal growth restriction, with larger risks among complicated pregnancies. METHODS: A multiyear linked birth certificate and maternal/newborn hospital discharge dataset of singleton, term births to mothers residing in New Jersey at the time of birth, who were white (non-Hispanic), African-American (non-Hispanic) or Hispanic was used. Very small for gestational age (VSGA) was defined as a fetal growth ratio <0.75, small for gestational age (SGA) as > or =0.75 and <0.85, and 'reference' births as > or =0.85. Using polytomous logistic regression, associations between mean pollutant concentrations during the first, second and third trimesters and the risks of SGA/VSGA were examined, as well as effect modification of these associations by several pregnancy complications. RESULTS: Significantly increased risk of SGA was associated with first and third trimester PM(2.5) (particulate matter <2.5 microm in aerodynamic diameter), and increased risk of VSGA associated with first, second and third trimester nitrogen dioxide (NO(2)) concentrations. Pregnancies complicated by placental abruption and premature rupture of the membrane had approximately two- to fivefold greater excess risks of SGA/VSGA than pregnancies not complicated by these conditions, although these estimates were not statistically significant. CONCLUSIONS: These findings suggest that ambient air pollution, perhaps specifically traffic emissions during early and late pregnancy and/or factors associated with residence near a roadway during pregnancy, may affect fetal growth. Further, pregnancy complications may increase susceptibility to these effects in late pregnancy.

Risk factors for intrapair birth weight discordance in twins.

OBJECTIVES: To determine the risk factors for birth weight discordance in twins. METHODS: We used the United States (1995-97) Matched Multiple Birth File (n = 294 568) to assess the association between birth weight discordance and maternal sociodemographic, pregnancy and infant characteristics. RESULTS: Eighty-four per cent of the twins were 0-19% discordant, 11.1% were 20-29% discordant, 3.4% were 30-39% discordant, and 1.8% were > or = 2 40% discordant. The risk factors for birth weight discordance for same-sex twins were eclampsia (odds ratio (OR) 1.39,95% confidence interval (CI) 1.20, 1.61), pre-eclampsia (OR 1.31, 95% CI 1.24, 1.38), pre-existing hypertension (OR 1.32, 95% CI 1.12, 1.56), diabetes (OR 1.13, 95% CI 1.04, 1.24) and certain congenital anomalies. For opposite-sex twins, the risk factors for birth weight discordance were pre-eclampsia (OR 1.17, 95% CI 1.09, 1.27), pre-existing hypertension (OR 1.59,95% CI 1.32, 1.91), and certain congenital anomalies. Also, smoking and increased maternal age were associated with birth weight discordance in both same-sex and opposite-sex twins. CONCLUSIONS: Maternal hypertensive disorders, smoking and delayed childbearing were associated with intrapair birth weight discordance. The mechanisms of these associations deserve further investigation.

Risk of abruptio placentae by region of birth and residence among African-American women in the USA.

OBJECTIVE: To determine whether Southern-born African-American women have higher incidence of abruptio placentae, irrespective of their region of residence. METHODS: For this retrospective cohort study we used vital statistics data of the US for the years 1995 and 1996. Age-adjusted rates of abruption were derived for combinations of regions of birth (Northeast, Midwest, South, West, and Foreign-born) and regions of residence (Northeast, Midwest, South, and West) for all singleton live births among African-American women. RESULTS: The incidence of abruptio placentae among African-American women was 6.7 per 1,000 live births. The age-adjusted rates of abruption among women who had not migrated showed that those in the Northeast had the highest rates (8.3 per 1,000), followed by those in the Midwest (6.3 per 1,000), South (6.0 per 1,000) and in the West (4.9 per 1,000). The prevalence of risk factors showed the same pattern. CONCLUSION: The results of the study suggest that place of residence rather than place of birth was associated with the risk of placental abruption. However, foreign-born African-American women had lower rates of abruption irrespective of the region of residence.

Level of maternal antibody required to protect neonates against early-onset disease caused by group B Streptococcus type Ia: a multicenter, seroepidemiology study.

Because of the difficulty of conducting efficacy trials of vaccines against group B streptococcus (GBS), the licensure of these vaccines may have to rely on studies that measure vaccine-induced antibody levels that correlate with protection. This study estimates the level of maternal antibody required to protect neonates against early-onset disease (EOD) caused by GBS type Ia. Levels of maternal serum IgG GBS Ia antibodies, measured by ELISAs in 45 case patients (neonates with EOD caused by GBS Ia) and in 319 control subjects (neonates colonized by GBS Ia but without EOD) born at > or =34 weeks gestation were compared. The probability of developing EOD declined with increasing maternal levels of IgG GBS Ia antibody (P = .03). Neonates whose mothers had levels of IgG GBS Ia antibody > or =5 microg/mL had an 88% lower risk (95% confidence interval, 7%-98%) of developing type-specific EOD, compared with those whose mothers had levels < 0.5 microg/mL. A vaccine that induces IgG GBS Ia antibody levels > or =5 microg/mL in mothers can be predicted to confer a high degree of type-specific immunity to EOD to their infants.

The efficacy of the non-stress test in preventing fetal death in post-term pregnancy.

We conducted a case--control study to examine the efficacy of non-stress testing in preventing fetal death in post-term pregnancy. The analysis was based on data from the 1988 National Maternal and Infant Health Survey, which was a nationally representative sample of live births, fetal deaths and infant deaths that occurred in 1988. Information on whether a woman had non-stress testing was obtained from a questionnaire sent to prenatal care providers and hospitals. Cases were post-term women (with 42 weeks or more gestation) who had fetal deaths. Three post-term controls, who had live births and who delivered at the same time or later than the cases, were randomly chosen and individually matched to each case by maternal race. The proportion of women who had one or more non-stress tests during pregnancy was compared between cases and controls. Non-stress testing was used in 30.9% of the 126 cases and in 28.5% of the 375 controls. The race-adjusted odds ratio for exposure to non-stress test was 1.12 [95% CI 0.72, 1.75]. After controlling for other important confounding variables the odds ratio was 1.05 [95% CI 0.57, 1.91]. These results do not support the efficacy of non-stress testing in post-term pregnancies. A more detailed evaluation of this widely used screening procedure is needed.

Trends in preterm birth and neonatal mortality among blacks and whites in the United States from 1989 to 1997.

Preterm birth, a major determinant of infant mortality, has been increasing in recent years. The authors examined trends in preterm birth and its determinants by using the US birth and infant death files for 1989-1997. The impact of trends in preterm birth rates on neonatal and infant mortality was also evaluated. Among Whites, preterm births (<37 completed weeks of gestation) increased from 8.8% of livebirths in 1989 to 10.2% in 1997, a relative increase of 15.6%. On the other hand, preterm births among Blacks decreased by 7.6% (from 19.0% to 17.5%) during the same period. An increase in obstetric interventions contributed to increases in preterm births for both races but was outweighed by other unidentified favorable influences for Blacks. Neonatal mortality among preterm Whites dropped 34% during the 8 years of the study, while the decrease was only 24% among Blacks. This large disparity countered the changes in preterm birth rates so that the percentage decline in neonatal mortality was similar in the two racial groups (18-20%). In conclusion, the anticipated mortality benefit from a lower preterm birth rate for Blacks has been blunted by suboptimal improvement in mortality among the remaining preterm infants. The widening race gap in mortality among preterm infants merits attention.

Association of maternal fever during labor with neonatal and infant morbidity and mortality.

OBJECTIVE: To examine the association of intrapartum fever with infant morbidity and early neonatal (0-6 days) and infant (0-364 days) death. METHODS: We carried out a retrospective cohort analysis among singleton live births in the United States for the period 1995-1997 using the National Center for Health Statistics linked birth-infant death cohort data. RESULTS: Among the 11,246,042 singleton live births during the study period, intrapartum fever (at least 38C) was recorded in 1.6%. Intrapartum fever was associated with early neonatal (adjusted odds ratio [OR], 95% confidence interval [CI] for preterm and term infants respectively: 1.32; 1.11, 1.56 and 1.67; 1.14, 2.46) and infant (OR, 95% CI for preterm and term, respectively: 1.31; 1.14, 1.51 and 1.27; 1.01, 1.59) death among nulliparous mothers. Among preterm infants of parous mothers, intrapartum fever was associated with early neonatal (OR 1.29, 95% CI 1.01, 1.64) death. In the combined analyses (infants of nulliparous and parous mothers), intrapartum fever was a strong predictor of infection-related death. These associations were stronger among term (OR 3.16, 95% CI 1.56, 6.40 for early neonatal; OR 1.75, 95% CI 1.20, 2.57 for infant death) than preterm infants (OR 1.52, 95% CI 1.15, 2.00 for early neonatal; OR 1.29, 95% CI 1.05, 1.57 for infant death). Intrapartum fever was also a risk factor for meconium aspiration syndrome, hyaline membrane disease, neonatal seizures, and assisted ventilation. CONCLUSION: Intrapartum fever is an important predictor of neonatal morbidity and infection-related mortality.

The effect of chelation therapy with succimer on neuropsychological development in children exposed to lead.

BACKGROUND: Thousands of children, especially poor children living in deteriorated urban housing, are exposed to enough lead to produce cognitive impairment. It is not known whether treatment to reduce blood lead levels prevents or reduces such impairment. METHODS: We enrolled 780 children with blood lead levels of 20 to 44 microg per deciliter (1.0 to 2.1 micromol per liter) in a randomized, placebo-controlled, double-blind trial of up to three 26-day courses of treatment with succimer, a lead chelator that is administered orally. The children lived in deteriorating inner-city housing and were 12 to 33 months of age at enrollment; 77 percent were black, and 5 percent were Hispanic. Follow-up included tests of cognitive, motor, behavioral, and neuropsychological function over a period of 36 months. RESULTS: During the first six months of the trial, the mean blood lead level in the children given succimer was 4.5 microg per deciliter (0.2 micromol per liter) lower than the mean level in the children given placebo (95 percent confidence interval, 3.7 to 5.3 microg per deciliter [0.2 to 0.3 micromol per liter]). At 36 months of follow-up, the mean IQ score of children given succimer was 1 point lower than that of children given placebo, and the behavior of children given succimer was slightly worse as rated by a parent. However, the children given succimer scored slightly better on the Developmental Neuropsychological Assessment, a battery of tests designed to measure neuropsychological deficits thought to interfere with learning. All these differences were small, and none were statistically significant. CONCLUSIONS: Treatment with succimer lowered blood lead levels but did not improve scores on tests of cognition, behavior, or neuropsychological function in children with blood lead levels below 45 microg per deciliter. Since succimer is as effective as any lead chelator currently available, chelation therapy is not indicated for children with these blood lead levels.

The effectiveness of risk-based intrapartum chemoprophylaxis for the prevention of early-onset neonatal group B streptococcal disease.

OBJECTIVE: Our purpose was to evaluate the effectiveness of a risk-based intrapartum antibiotic prophylaxis strategy for the prevention of early-onset neonatal group B streptococcal disease. STUDY DESIGN: Cases and controls were selected from infants born to women with one or more risk factors: preterm labor or rupture of membranes, prolonged rupture of membranes (>18 hours), fever during labor, or previous child with group B streptococcal disease. Cases were matched with controls by birth hospital and gestational age. Data abstracted from medical records were analyzed to estimate the effectiveness of intrapartum antibiotic prophylaxis. RESULTS: We analyzed data from 109 cases and 207 controls. Nineteen (17%) case versus 69 (33%) control mothers received an acceptable regimen of intrapartum antibiotic prophylaxis. In adjusted analyses, the effectiveness of intrapartum antibiotic prophylaxis was 86% (95% confidence interval, 66%-94%). When the first dose of antibiotics was given > or =2 hours before delivery, the effectiveness increased to 89% (95% confidence interval, 70%-96%); when it was given within 2 hours of delivery, the effectiveness was 71% (95% confidence interval, -8%-92%). Effectiveness was lowest in mothers with intrapartum fever (72%, 95% confidence interval, -9%-93%). On the basis of a 70% prevalence of maternal risk factors expected among cases in the absence of intrapartum antibiotic prophylaxis, we estimate that the risk-based strategy could reduce early-onset group B streptococcal disease by 60%. CONCLUSIONS: The risk-based approach to intrapartum antibiotic prophylaxis is effective in preventing early-onset group B streptococcal disease. To achieve the maximum preventive effect, the first dose of antibiotics should be administered at least 2 hours before delivery.

Level of aggregation for optimal epidemiological analysis: the case of time to surgery and unnecessary removal of the normal appendix.

STUDY OBJECTIVE: To illustrate the concept of "individualised fallacy", the result of improper interpretation and inference about aggregate level associations on the basis of associations at the individual level, in epidemiology. DESIGN: Cohort study. SETTING: Canadian province of Ontario. PATIENTS: All patients who underwent primary appendicectomy in 175 Ontario hospitals from 1989 to 1992. The association between rate of normal appendix removal and time to surgery was analysed at two levels: (1) at individual patient level, in which, for each patient, the exact number of days to surgery was derived, and (2) at hospital level, in which hospital specific proportions of time to surgery was calculated. MAIN RESULTS: Measured at individual level, compared with patients who had an operation on the same day of admission, the odds ratio was 2.41 (95% confidence intervals 2.28, 2.56) for patients who had an operation > 1 day after admission. Measured at hospital level, each 10% increase in the proportion of patients who had an operation > 1 day after admission resulted in a 15% reduction in the odds of normal appendix removal (odds ratio 0.85, 95% confidence intervals 0.82, 0.88) CONCLUSIONS: In this case study, hospital level measure correctly predicted a reduction in the rate of normal appendix removal by delaying surgery, whereas individual level measure biased the direction of the relation to the opposite. This example illustrates that bias in across level inference can occur either at individual or ecological level. The preferred level of analysis is the one that minimises confounding; often, it must be selected on the basis of a priori knowledge of the subject area.

Antibiotic susceptibility profiles for group B streptococci isolated from neonates, 1995-1998.

Antibiotic susceptibility profiles were analyzed for 119 invasive and 227 colonizing strains of group B streptococci isolated from neonates at 6 US academic centers. All strains were susceptible to penicillin, vancomycin, chloramphenicol, and cefotaxime. The rate of resistance to erythromycin was 20.2% and to clindamycin was 6.9%. Resistance to erythromycin increased in 1997. Type V strains were more resistant to erythromycin than were type Ia (P=.003) and type Ib (P=.004) strains and were more resistant to clindamycin than were type Ia (P<.001), type Ib (P=.01), and type III (P=.001) strains. Resistance rates varied with geographic region: in California, there were high rates of resistance to erythromycin and clindamycin (32% and 12%, respectively), and low rates in Florida (8.5% and 2.1%, respectively). Penicillin continues to be the drug of choice for treatment of group B streptococcus infection. For women who are penicillin intolerant, however, the selection of an alternative antibiotic should be guided by contemporary resistance patterns observed in that region.

Ethnic and racial differences in prostate cancer incidence and mortality.

Prostate cancer (CaP) incidence and mortality vary strikingly among ethnic, racial, and national groups. There is evidence that genetic, environmental, and social factors jointly-and often in combination-contribute to the observed differences in various populations. Noteworthy is the high rate of both CaP incidence and mortality among African Americans. Changes in the epidemiology of CaP since the advent of prostate specific antigen testing suggest that improved access to screening and treatment may serve to reduce somewhat the differences between the white and African-American populations. However, because the causes of these differences are likely to be multifactorial, a variety of strategies addressing the range of causes will be necessary to reduce the excess African-American mortality from this disease.

Seasonal influences on childhood lead exposure.

We conducted a study to examine seasonal changes in residential dust lead content and its relationship to blood lead in preschool children. We collected blood and dust samples (floors, windowsills, and carpets) to assess lead exposure. The geometric mean blood lead concentrations are 10.77 and 7.66 microg/dL for the defined hot and cold periods, respectively (p < 0.05). Lead loading (milligrams per square meter) is the measure derived from floor and windowsill wipe samples that is most correlated with blood lead concentration, whereas lead concentration (micrograms per gram) is the best variable derived from carpet vacuum samples. The variation of dust lead levels for these three dust variables (floor lead loading, windowsill lead loading, and carpet lead concentration) are consistent with the variation of blood lead levels, showing the highest levels in the hottest months of the year, June, July, and August. The regression analysis, including the three representative dust variables in the equations to predict blood lead concentration, suggests that the seasonality of blood lead levels in children is related to the seasonal distributions of dust lead in the home. In addition, the outdoor activity patterns indicate that children are likely to contact high leaded street dust or soil during longer outdoor play periods in summer. Consequently, our results show that children appear to receive the highest dust lead exposure indoors and outdoors during the summer, when they have the highest blood lead levels. We conclude that at least some of the seasonal variation in blood lead levels in children is probably due to increased exposure to lead in dust and soil.

Impact of geographic proximity to cardiac revascularization services on service utilization.

BACKGROUND: In a highly competitive health care environment, even microgeographic differences in availability of tertiary services might affect access to care. OBJECTIVES: To study the impact of (1) geographic distance from patient's residence to cardiac revascularization services and (2) the availability of cardiac revascularization services at the hospital nearest the patient's residence on utilization of these services in a geographically small, densely populated area. METHODS: Historical cohort study of 55,659 New Jersey residents hospitalized between 1992 and 1996 with primary diagnosis of acute myocardial infarction (AMI). MAIN STUDY OUTCOMES: Use of percutaneous transluminal coronary angioplasty (PTCA) or coronary artery bypass graft surgery (CABG) within 90 days of initial hospitalization for AMI and in-hospital mortality. Distance from patient's residence to nearest hospital with cardiac revascularization services (PTCA and CABG) was a straight-line distance in miles, categorized as 0 to <2, 2 to <5, 5 to <10, 10 to <15, 15 to <20, 20 to <25, > or =25 miles. Adjusted odds of PTCA or CABG use at each distance category were compared with odds at > or =25 miles. RESULTS: A strong linear decline in adjusted odds ratios for PTCA use was found with increasing distance of this service from the patient's residence (p <0.05). Adjusted odds of PTCA use were 2.4, 2.1, 1.8, 1.5, 1.3, and 1.0 times higher for each increasing distance category in comparison with > or =25 for patients aged <65 and 3.1, 2.7, 2.2, 1.9, 1.7, and 1.1 for patients aged > or =65. Use of CABG was also higher for patients residing closer to cardiac revascularization services. The availability of these services at the hospital nearest to the patient's residence also increased utilization. In-hospital mortality was not associated with distance from services. CONCLUSION: Even across a relatively small geographic area, shorter distance to services and availability of services at the nearest hospital were strongly related to increased utilization of cardiac revascularization services.

Impact of availability of hospital-based invasive cardiac services on racial differences in the use of these services.

BACKGROUND: Reports indicate that black patients are less likely than white patients to receive invasive cardiac services after hospitalization for acute myocardial infarction (AMI). There is still uncertainty as to why racial differences exist and how they affect patient outcomes. This is the first study to focus on the availability of invasive cardiac services and racial differences in procedure use. Study objectives were to (1) document whether racial differences existed in the use of invasive cardiac procedures, (2) study whether these racial differences were related to availability of hospital-based invasive cardiac services at first admission for AMI, and (3) determine whether there were racial differences in long-term mortality rates. METHODS: A historical cohort study was conducted with discharge records from all acute care hospitals in New Jersey for 1993 linked to death certificate records for 1993 and 1994. There were 13,690 black and white New Jersey residents hospitalized with primary diagnosis of AMI. Use of cardiac catheterization within 90 days, revascularization within 90 days (percutaneous transluminal coronary angioplasty [PTCA] or coronary artery bypass graft surgery [CABG]), and death within 1 year after admission for AMI were the main outcome measures. Patterns for PTCA and CABG as separate outcomes were also studied. Hospital-based cardiac services available were described as no invasive cardiac services, catheterization only, or PTCA/CABG. To account for payer status and comorbidity differences, patients 65 years and older with Medicare coverage were analyzed separately from those younger than 65 years. RESULTS: Black patients aged 65 and older were generally less likely to receive catheterization and revascularization than white patients, regardless of facilities available at first admission. For patients younger than 65 years, the greatest differences between black and white patients in catheterization and PTCA/CABG use within 90 days after AMI occurred when no hospital-based invasive cardiac services were available. However, use of invasive cardiac procedures within 90 days after AMI was substantially increased if the first hospital offered catheterization only or PTCA/CABG services, among all patients, especially among blacks younger than age 65. No significant racial differences or interactions with available services were found in 1-year mortality rates. CONCLUSIONS: Availability of invasive cardiac services at first hospitalization for AMI was associated with increased procedure use for both races. However, use of invasive cardiac procedures was generally lower for black patients than for white patients, regardless of services available. Long-term mortality rates after hospitalization for AMI did not differ between blacks and whites.

No difference in iron status between children with low and moderate lead exposure.

We compared the iron status between children 11 to 33 months old with confirmed blood lead levels of 20 to 44 microg/dL and demographically similar children with blood lead levels of <10 microg/dL. There were no differences. Laboratory investigation or empirical treatment for iron deficiency is not justified on the basis of moderately elevated blood lead levels alone.

A field comparison of two methods for sampling lead in household dust.

Comparability of dust lead measurements has been a difficult problem due to different sampling and analysis techniques. This paper compares two dust sampling techniques, the U.S. Department of Housing and Urban Development (HUD) dust wipe method and the Lioy, Wainman, Weisel (LWW) sampler. The HUD method specifies using a moist towelette to pick up as much dust as possible in a specified area and estimates total lead loading. The LWW sampler collects the dust on preweighed wetted filter media, and provides greater standardization of the sampling path and pressure applied. LWW samples were analyzed using inductively coupled plasma mass spectronomy (no samples below minimum detection limit), while HUD samples were analyzed using flame atomic absorption (32% of samples below minimum detection limit). A bootstrapping technique was used in the analysis to contend with those HUD samples below the minimum detection limit. Mixed model equations were generated to predict HUD values from LWW results, and to examine the effects of sampling location, time, and method. The results indicate that the two samplers performed similarly under field conditions, although the LWW sampler produced consistently lower lead loading estimates. LWW values that predicted HUD lead clearance values of 100 micrograms/ft2 for floors and 500 micrograms/ft2 for window sills were 72 micrograms/ft2 and 275 micrograms/ft2, respectively. To examine internal reproducibility, duplicate samples were taken using both the HUD and LWW methods. Correlation results within paired samples indicated a statistically significantly higher (p < 0.001) internal reproducibility for lead loading, for the LWW sampler (r = 0.87), than for the HUD method (r = 0.71). Some of the differences appeared to be related to the analytical methods.