Ann C. Trumble

Risk factors for infant homicide in the United States.

BACKGROUND Homicide is the leading cause of infant deaths due to injury. More than 80 percent of infant homicides are considered to be fatal child abuse. This study assessed the timing of deaths and risk factors for infant homicide. METHODS Using linked birth and death certificates for all births in the U.S. between 1983 and 1991, we identified 2776 homicides occurring during the first year of life. Birth-certificate variables were reviewed in both bivariate and multivariate stratified analyses. Variables potentially predictive of homicide were selected on the basis of increased relative risks among subcategories with adequate numbers for stable estimates. RESULTS Half the homicides occurred by the fourth month of life. The most important risk factors were a second or subsequent infant born to a mother less than 17 years old (relative risk, 10.9) or 17 to 19 years old (relative risk, 9.3), as compared with a first infant born to a mother 25 years old or older; a maternal age of less than 15 years, as compared with an age of at least 25 years (relative risk, 6.8); no prenatal care as compared with early prenatal care (relative risk, 10.4); and less than 12 years of education among mothers who were at least 17 years old (relative risk, 8.0), as compared with 16 or more years of education. CONCLUSIONS Childbearing at an early age was strongly associated with infant homicide, particularly if the mother had given birth previously. Our findings may have implications for prevention.

Severe Maternal Morbidity Associated with Hypertensive Disorders in Pregnancy in the United States

Objectives: This study was to report the incidence of severe maternal morbidity associated with hypertensive disorders of pregnancy in the United States. Study Design: We used data from the National Hospital Discharge Survey, a nationally representative sample of discharge records, from 1988 to 1997. The database consisted of approximately 300,000 deliveries, which represented 39 million births during the 10‐year period. Results: The overall incidence of hypertensive disorders in pregnancy was 5.9% [95% confidence interval (CI): 5.2 to 6.5%]. Eclampsia was reported at 1.0 per 1000 deliveries (95% CI: 0.8 to 1.2). The incidence of eclampsia, severe preeclampsia, and superimposed preeclampsia remained unchanged during the 10‐year period. Women with preeclampsia and eclampsia had a 3‐ to 25‐fold increased risk of severe complications, such as abruptio placentae, thrombocytopenia, disseminated intravascular coagulation, pulmonary edema, and aspiration pneumonia. More than half of women with preeclampsia and eclampsia had cesarean delivery. African American women not only had higher incidence of hypertensive disorders in pregnancy but also tended to have a greater risk for most severe complications. Preeclamptic and eclamptic women younger than 20 years or older than 35 years had substantially higher morbidity. Conclusion: Preeclampsia and eclampsia carry a high risk for severe maternal morbidity. Compared to Caucasians, African Americans have higher incidence of hypertensive disorders in pregnancy and suffer from more severe complications.

Deaths attributable to injuries in infants, United States, 1983-1991

Objective To describe risk factors for injury death among infants in the United States by the specific external cause of death. Methods. Data were analyzed from the US-linked birth/infant death files for the years 1983–1991. Potential risk factors for injury death were identified from birth certificate data and included both maternal and infant factors. Injury rates were calculated by external cause of death. Characteristics of infants who died from an injury were compared with those of the entire birth cohort. The independent effect of potential risk factors was assessed in multivariate analyses using a case–control study design. Results. A total of 10 370 injury deaths were identified over the 9-year study period (29.72/100 000 live births). The leading causes of death were homicide, suffocation, motor vehicle crashes, and choking (inhalation of food or objects). There was no significant temporal trend in the overall rate of injury death; however, this was because significant increases in the rates of death from homicide (6.4%/year) and mechanical suffocation (3.7%/year) were offset by decreases in rates of death from fires (−4.7%/year) and choking (−4.6%/year). In adjusted analyses, infants born to mothers with no prenatal care, <12 years of education, two or more previous live births, Native American race, or <20 years of age were at twice the risk of injury death compared with the lowest risk groups (initiation of prenatal care in the first trimester, ≥16 years of education, no previous live births, white, or ≥25 years of age). When analyzed by the specific cause of death, the factors that were associated most strongly with death varied. For example, Native Americans were at greatest risk of a motor vehicle related death (compared with whites: OR: 3.6; 95% CI: 1.8–7.1), and infants with birth weights of <1500 g were at greatest risk of death attributable to inhalation of food (compared with ≥2500 g: OR: 9.6; 95% CI: 3.3–28.0) or objects (OR: 11.8; 95% CI: 4.5–30.5). Conclusion. A number of sociodemographic characteristics are associated with an increased risk of injury-related death in infants. The strength of associations between specific risk factors and death varies with the external cause of death, thus identifying high-risk subgroups for targeting of cause-specific interventions and simultaneously increasing our understanding of the individual and societal mechanisms underlying these tragedies. infant, injury, suffocation, motor vehicle, homicide, drowning, inhalation, fire.

Swimming Pool Drownings Among US Residents Aged 5-24 Years: Understanding Racial/Ethnic Disparities

OBJECTIVE We examined circumstances surrounding swimming pool drownings among US residents aged 5 to 24 years to understand why Black males and other racial/ethnic groups have high drowning rates. METHODS We obtained data about drowning deaths in the United States (1995-1998) from death certificates, medical examiner reports, and newspaper clippings collected by the US Consumer Product Safety Commission. RESULTS During the study period, 678 US residents aged 5 to 24 years drowned in pools. Seventy-five percent were male, 47% were Black, 33% were White, and 12% were Hispanic. Drowning rates were highest among Black males, and this increased risk persisted after we controlled for income. The majority of Black victims (51%) drowned in public pools, the majority of White victims (55%) drowned in residential pools, and the majority of Hispanic victims (35%) drowned in neighborhood pools (e.g., an apartment complex pool). Foreign-born males also had an increased risk for drowning compared with American-born males. CONCLUSIONS Targeted interventions are needed to reduce the incidence of swimming pool drownings across racial/ethnic groups, particularly adult supervision at public pools.

Analysis of repeated pregnancy outcomes

Women tend to repeat reproductive outcomes, with past history of an adverse outcome being associated with an approximate two-fold increase in subsequent risk. These observations support the need for statistical designs and analyses that address this clustering. Failure to do so may mask effects, result in inaccurate variance estimators, produce biased or inefficient estimates of exposure effects. We review and evaluate basic analytic approaches for analysing reproductive outcomes, including ignoring reproductive history, treating it as a covariate or avoiding the clustering problem by analysing only one pregnancy per woman, and contrast these to more modern approaches such as generalized estimating equations with robust standard errors and mixed models with various correlation structures. We illustrate the issues by analysing a sample from the Collaborative Perinatal Project dataset, demonstrating how the statistical model impacts summary statistics and inferences when assessing etiologic determinants of birth weight.

Socioeconomic and racial/ethnic factors affecting non-fatal medically attended injury rates in US children.

OBJECTIVE: Using a representative survey of US children, the purpose was to evaluate separate effects of socioeconomic and racial/ethnic factors, including access to care, on medically attended non-fatal injury rates. METHODS: Multivariate linear regression models were used to determine associations between injuries and health care coverage (insurance or Medicaid), having a place to go for care, race/ethnicity, maternal education, number of adults and children in the household, poverty, and urbanicity. The 1988 Child Health Supplement to the National Health Interview Survey included questions on medically attended injuries, and their cause, location, and effects on the child. Injury categories included total, consequential, occurrence at home or school, falls, and being struck or cut. RESULTS: Lack of health care coverage was consistently associated with lower medically attended injury rates in non-Hispanic blacks or whites and Mexican-Americans, but affected total rates for each group differently due to unequal distribution of health care coverage. Injuries occurred about 40% more frequently to children and adolescents living in single adult households compared with two adult homes for all injury categories except for injuries occurring at school. CONCLUSIONS: Preventive interventions targeted to specific populations based on assumptions that poverty, lack of education, or minority status result in greater risks for injuries require a closer look. Efficient targeting should address underlying factors such as differences in exposures and environments associated with single adult homes or recreational activities. Data sources used to target high risk populations for interventions need to address bias due to access to care.

Infant injury deaths with unknown intent: what else do we know?

Objectives—Strong evidence based on case record reviews indicates that the incidence of child homicide reported from death certificates is under ascertained. The characteristics of infant injury fatalities with undetermined, but suspicious, intent were compared for the probability that they should be considered homicides. Methods—Using linked birth and death certificates for all birth cohorts in the US from 1983–91, 2345 injury fatalities reported as intentional, 7594 as unintentional, and 431 as undetermined intent were identified. Maternal and infant variables potentially predictive of injury fatalities were selected based on increased bivariate associations. Relative risks of injury death by intentional, unintentional, and undetermined intent were assessed for maternal and infant characteristics. Results—Relative risks were consistently higher across all intent categories for infants of mothers with the least education, no prenatal care, young maternal age, and single marital status, as well as for infants who are second or later born, preterm, black, or American Indian. Fatalities with undetermined intent have larger relative risks in the highest risk categories than either intentional or unintentional injuries. Deaths with undetermined intent have risk profiles that more closely resemble profiles for intentional deaths than unintentional. Conclusions—Injury homicide rates would be almost 20% greater than official classifications indicate if deaths with undetermined intent were included. In analyses of infant homicide, excluding deaths of undetermined intent may lead to an underestimation of the magnitude of the public health problem of intentional injuries among infants. Other studies based on record reviews from multiple sources indicate that misclassification and under ascertainment of homicides may be even greater.

Persistent Lipophilic Environmental Chemicals and Endometriosis: The ENDO Study

Background: An equivocal literature exists regarding the relation between persistent organochlorine pollutants (POPs) and endometriosis in women, with differences attributed to methodologies. Objectives: We assessed the association between POPs and the odds of an endometriosis diagnosis and the consistency of findings by biological medium and study cohort. Methods: Using a matched cohort design, we assembled an operative cohort of women 18–44 years of age undergoing laparoscopy or laparotomy at 14 participating clinical centers from 2007 to 2009 and a population-based cohort matched on age and residence within a 50-mile catchment area of the clinical centers. Endometriosis was defined as visualized disease in the operative cohort and as diagnosed by magnetic resonance imaging in the population cohort. Logistic regression analysis was used to estimate odds ratios (ORs) and 95% confidence intervals (CIs) for each POP in relation to an endometriosis diagnosis, with separate models run for each medium (omental fat in the operative cohort, serum in both cohorts) and cohort. Adjusted models included age, body mass index, breast-feeding conditional on parity, cotinine, and lipids. Results: Concentrations were higher in omental fat than in serum for all POPs. In the operative cohort, γ-hexachlorocyclohexane (γ-HCH) was the only POP with a significant positive association with endometriosis [per 1-SD increase in log-transformed γ-HCH: adjusted OR (AOR) = 1.27; 95% CI: 1.01, 1.59]; β-HCH was the only significant predictor in the population cohort (per 1-SD increase in log-transformed β-HCH: AOR = 1.72; 95% CI: 1.09, 2.72). Conclusions: Using a matched cohort design, we found that cohort-specific and biological-medium–specific POPs were associated with endometriosis, underscoring the importance of methodological considerations when interpreting findings.

Effects of folic acid fortification on twin gestation rates

OBJECTIVE: Previous studies have reported an increase in twinning of as much as 40% associated with folic acid–containing supplements, and folic acid fortification of enriched cereal grains was authorized in 1996. The purpose of this study was to investigate whether twinning rates have increased since that time. METHODS: We used United States birth and fetal death records to calculate twin gestation rates from 1990 through 2000. To eliminate the influence of fertility treatments, our analysis was limited to nulliparous women aged 16–19. We compared time trends in twin gestation rates before and after folic acid fortification in 1996. RESULTS: A total of 25,065 twin and 3,362,245 singleton pregnancies were included. Twin gestation rates were stable from January 1990 through December 1996, at 7.2 per 1,000, and then began a steady increase, averaging 2.4% (95% confidence interval 0.1–4.2%, P = .006) per year, which continued through 2000 and reached 8.2 per 1,000. This translates to 2 additional twin pregnancies per 10,000 gestations per year. Twin rates continued to increase well beyond 1998, when the maximal fortification effect on folate status had been reached. CONCLUSION: Although twin gestation rates in women not using fertility treatments increased after food fortification with folic acid, they rose by much less than the 40% rate previously reported; the observed pattern of increase in twin gestation rates is not consistent with a folic acid fortification effect. LEVEL OF EVIDENCE: II-2

Unintentional injuries among youth with developmental disabilities in the United States, 2006–2007

We examined unintentional injury among youth with and without developmental disabilities. Our nationally representative sample included 6369 injured youth, aged 0–17 years, who were seen in one of the 63 US hospital emergency rooms that participated in the National Electronic Injury Surveillance System – All Injury Program (NEISS-AIP) in 2006–2007. Parents or guardians of injured youth were interviewed by telephone after the hospital visit to ascertain disability status. Denominator data were obtained from the National Health Interview Survey. Leading causes of injury were comparable for youth with and without disability. Injury rates (per 100 youth per year) were also comparable [10.4; 95% confidence interval (CI) 7.8, 13.0 and 10.5; 95% CI 8.2, 12.9, for youth with and without disability, respectively]. When examined by specific disability, the rate ratio for youth with learning disabilities versus youth without learning disability was 1.57 (95% CI 1.04, 2.10), which may represent a subgroup for targeted interventions.