Severe Acute Respiratory Syndrome Coronavirus 2 Seropositivity among Healthcare Personnel in Hospitals and Nursing Homes, Rhode Island, USA, July-August 2020.

Healthcare personnel are recognized to be at higher risk for infection with severe acute respiratory syndrome coronavirus 2. We conducted a serologic survey in 15 hospitals and 56 nursing homes across Rhode Island, USA, during July 17-August 28, 2020. Overall seropositivity among 9,863 healthcare personnel was 4.6% (95% CI 4.2%-5.0%) but varied 4-fold between hospital personnel (3.1%, 95% CI 2.7%-3.5%) and nursing home personnel (13.1%, 95% CI 11.5%-14.9%). Within nursing homes, prevalence was highest among personnel working in coronavirus disease units (24.1%; 95% CI 20.6%-27.8%). Adjusted analysis showed that in hospitals, nurses and receptionists/medical assistants had a higher likelihood of seropositivity than physicians. In nursing homes, nursing assistants and social workers/case managers had higher likelihoods of seropositivity than occupational/physical/speech therapists. Nursing home personnel in all occupations had elevated seropositivity compared with hospital counterparts. Additional mitigation strategies are needed to protect nursing home personnel from infection, regardless of occupation.

Coronavirus Disease 2019 Symptoms and Severe Acute Respiratory Syndrome Coronavirus 2 Antibody Positivity in a Large Survey of First Responders and Healthcare Personnel, May-July 2020.

A severe acute respiratory syndrome coronavirus 2 serosurvey among first responder/healthcare personnel showed that loss of taste/smell was most predictive of seropositivity; percent seropositivity increased with number of coronavirus disease 2019 symptoms. However, 22.9% with 9 symptoms were seronegative, and 8.3% with no symptoms were seropositive. These findings demonstrate limitations of symptom-based surveillance and importance of testing.

Prevalence of SARS-CoV-2 Antibodies in First Responders and Public Safety Personnel, New York City, New York, USA, May-July 2020.

We conducted a serologic survey in public service agencies in New York City, New York, USA, during May-July 2020 to determine prevalence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection among first responders. Of 22,647 participants, 22.5% tested positive for SARS-CoV-2-specific antibodies. Seroprevalence for police and firefighters was similar to overall seroprevalence; seroprevalence was highest in correctional staff (39.2%) and emergency medical technicians (38.3%) and lowest in laboratory technicians (10.1%) and medicolegal death investigators (10.8%). Adjusted analyses demonstrated association between seropositivity and exposure to SARS-CoV-2-positive household members (adjusted odds ratio [aOR] 3.52 [95% CI 3.19-3.87]), non-Hispanic Black race or ethnicity (aOR 1.50 [95% CI 1.33-1.68]), and severe obesity (aOR 1.31 [95% CI 1.05-1.65]). Consistent glove use (aOR 1.19 [95% CI 1.06-1.33]) increased likelihood of seropositivity; use of other personal protective equipment had no association. Infection control measures, including vaccination, should be prioritized for frontline workers.

Assessing consent for and response to health survey components in an era of falling response rates: National Health and Nutrition Examination Survey, 2011-2018.

Response rates for national population-based surveys have declined, including the National Health and Nutrition Examination Survey (NHANES). Declining response to the initial NHANES interview may impact consent and participation in downstream survey components such as record linkage, physical exams, storage of biological samples and phlebotomy. Interview response rates dropped from 68% in 2011-2012 to 53% in 2017-2018 for adults age 18 and older. Response was higher for children (1-17 years) but with a similar downward trend (2011-2012, 81%; 2017-2018, 65%). Despite declining interview response rates, changes in consent and response rates for downstream components over time have been mixed. Among those interviewed, the examination response rate was over 93%, consent for record linkage was over 90%, and consent for storage of specimens for future research was over 99%. The availability of a blood sample for storage ranged between 60%-65% for children and 78%-85% for adults.

Lack of Antibodies to Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) in a Large Cohort of Previously Infected Persons.

BACKGROUND: Reports suggest that some persons previously infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) lack detectable immunoglobulin G (IgG) antibodies. We aimed to determine the proportion IgG seronegative and predictors for seronegativity among persons previously infected with SARS-CoV-2. METHODS: We analyzed serologic data collected from healthcare workers and first responders in New York City and the Detroit metropolitan area with a history of a positive SARS-CoV-2 reverse-transcription polymerase chain reaction (RT-PCR) test result and who were tested for IgG antibodies to SARS-CoV-2 spike protein at least 2 weeks after symptom onset. RESULTS: Of 2547 persons with previously confirmed SARS-CoV-2 infection, 160 (6.3%) were seronegative. Of 2112 previously symptomatic persons, the proportion seronegative slightly increased from 14 to 90 days post symptom onset (P = .06). The proportion seronegative ranged from 0% among 79 persons previously hospitalized to 11.0% among 308 persons with asymptomatic infections. In a multivariable model, persons who took immunosuppressive medications were more likely to be seronegative (31.9%; 95% confidence interval [CI], 10.7%-64.7%), while participants of non-Hispanic Black race/ethnicity (vs non-Hispanic White; 2.7%; 95% CI, 1.5%-4.8%), with severe obesity (vs under/normal weight; 3.9%; 95% CI, 1.7%-8.6%), or with more symptoms were less likely to be seronegative. CONCLUSIONS: In our population with previous RT-PCR-confirmed infection, approximately 1 in 16 persons lacked IgG antibodies. Absence of antibodies varied independently by illness severity, race/ethnicity, obesity, and immunosuppressive drug therapy. The proportion seronegative remained relatively stable among persons tested up to 90 days post symptom onset.

SARS-CoV-2 Seroprevalence among Healthcare, First Response, and Public Safety Personnel, Detroit Metropolitan Area, Michigan, USA, May-June 2020.

To estimate seroprevalence of severe acute respiratory syndrome 2 (SARS-CoV-2) among healthcare, first response, and public safety personnel, antibody testing was conducted in emergency medical service agencies and 27 hospitals in the Detroit, Michigan, USA, metropolitan area during May-June 2020. Of 16,403 participants, 6.9% had SARS-CoV-2 antibodies. In adjusted analyses, seropositivity was associated with exposure to SARS-CoV-2-positive household members (adjusted odds ratio [aOR] 6.18, 95% CI 4.81-7.93) and working within 15 km of Detroit (aOR 5.60, 95% CI 3.98-7.89). Nurse assistants (aOR 1.88, 95% CI 1.24-2.83) and nurses (aOR 1.52, 95% CI 1.18-1.95) had higher likelihood of seropositivity than physicians. Working in a hospital emergency department increased the likelihood of seropositivity (aOR 1.16, 95% CI 1.002-1.35). Consistently using N95 respirators (aOR 0.83, 95% CI 0.72-0.95) and surgical facemasks (aOR 0.86, 95% CI 0.75-0.98) decreased the likelihood of seropositivity.

Factors Associated with Prescription Opioid Analgesic Use in the US Population, 2011-2014.

OBJECTIVE: This study examined factors associated with prescription opioid analgesic use in the US population using data from a nationally representative sample. It focused on factors previously shown to be associated with opioid use disorder or overdose. Variations in the use of different strength opioid analgesics by demographic subgroup were also examined. METHODS: Data came from respondents aged 16 years and older who participated in the National Health and Nutrition Examination Survey (2011-2014). Respondents were classified as opioid users if they reported using one or more prescription opioid analgesics in the past 30 days. RESULTS: Opioid users reported poorer self-perceived health than those not currently using opioids. Compared with those not using opioids, opioid users were more likely to rate their health as being "fair" or "poor" (40.4% [95% confidence interval {CI} = 34.9%-46.2%] compared with 15.6% [95% CI = 14.3%-17.1%]), experienced more days of pain during the past 30 days (mean = 14.3 [95% CI = 12.9-15.8] days compared with 2.3 [95% CI = 2.0-2.7] days), and had depression (22.5% [95% CI = 17.3%-28.7%] compared with 7.1% [95% CI = 6.2%-8.0%]). Among those who reported using opioids during the past 30 days, 18.8% (95% CI = 14.4%-24.1%) reported using benzodiazepine medication during the same period and 5.2% (95% CI = 3.5%-7.7%) reported using an illicit drug during the past six months. When opioid strength was examined, a smaller percentage of adults aged 60 years and older used stronger-than-morphine opioids compared with adults aged 20-39 and 40-59 years. CONCLUSIONS: Higher percentages of current opioid users than nonusers reported having many of the factors associated with opioid use disorder and overdose.

Trends in the use of prescription antibiotics: NHANES 1999-2012.

OBJECTIVES: The objectives of this study were: to examine trends in the use of prescription antibiotics overall and by population subgroups between 1999 and 2012; and to examine trends in the use of categories of antibiotics and individual antibiotics. METHODS: Use of antibiotics was examined among 71 444 participants in the nationally representative National Health and Nutrition Examination Survey (NHANES; 1999-2012). Use of an antibiotic in the past 30 days was the main outcome variable. Analyses of trends were conducted overall and separately by population subgroups (i.e. age, sex, race/Hispanic origin, health insurance status and respiratory conditions) across four time periods (1999-2002, 2003-06, 2007-10 and 2011-12). RESULTS: The percentage of the US population that used a prescription antibiotic in the past 30 days significantly declined from 6.1% in 1999-2002 to 4.1% in 2011-12 (P < 0.001). Declines were also identified for five age groups (0-1 year, 6-11 years, 12-17 years, 18-39 years and 40-59 years), both sexes, non-Hispanic white and non-Hispanic black persons, persons with and without insurance and among those who currently had asthma. Significant declines were also observed for three categories of antibiotics (penicillins, cephalosporins and macrolide derivatives). Of the most common antibiotics prescribed, only amoxicillin use decreased significantly. CONCLUSIONS: Overall, there was a significant decline in the use of antibiotics between 1999-2002 and 2011-12. Due to concerns about antimicrobial resistance, it is important to continue monitoring the use of antibiotics.

National Health and Nutrition Examination Survey Biospecimen Program: NHANES III (1988-1994) and NHANES 1999-2014.

BACKGROUND: The National Health and Nutrition Examination Survey's 9NHANES) biospecimena program was formed to manage the collection of biospecimena (including serum, plasma, urine, and DNA) from NHANES cycles, the storage of biospecimens in NHANES biospecimens, accessing of biospecimens by researchers and the providing of resulting data to future researchers. Data from biospeceimen research can be combined with existing NHANES data. OBJECTIVE: This report provides background on the development of NHANES biorepositories and describes the collection, processing, and storing of biospecimens; ethical considerations and informed consent; and the proposal process for accessing biospecimens and resulting data. The number and types of biospecimens collected in each survey cycle from NHANES III (1988- 1994) through NHANES 1999-2014 are discussed so that researchers can understand what biospecimens are available if they are considering using NHANES biospecimens in their research.

Functional difficulties and school limitations of children with epilepsy: findings from the 2009-2010 National Survey of Children with Special Health Care Needs.

BACKGROUND: Epilepsy is a common serious neurologic disorder in children. However, most studies of children's functional difficulties and school limitations have used samples from tertiary care or other clinical settings. OBJECTIVE: To compare functional difficulties and school limitations of a national sample of US children with special health care needs (CSHCN) with and without epilepsy. METHODS: Data from the 2009-2010 National Survey of CSHCN for 31,897 children aged 6-17 years with and without epilepsy were analyzed for CSHCN in two groups: 1) CSHCN with selected comorbid conditions (intellectual disability, cerebral palsy, autism, or traumatic brain injury) and 2) CSHCN without these conditions. Functional difficulties and school limitations, adjusted for the effect of sociodemographic characteristics, were examined by epilepsy and comorbid conditions. RESULTS: Three percent of CSHCN had epilepsy. Among CSHCN with epilepsy 53% had comorbid conditions. Overall CSHCN with epilepsy, both with and without comorbid conditions, had more functional difficulties than CSHCN without epilepsy. For example, after adjustment for sociodemographic characteristics a higher percentage of children with epilepsy, compared to children without epilepsy, had difficulty with communication (with conditions: 53% vs. 37%, without conditions: 13% vs. 5%). Results for school limitations were similar. After adjustment, a higher percentage of children with epilepsy, compared to children without epilepsy, missed 11 + school days in the past year (with conditions: 36% vs. 18%, without conditions: 21% vs. 15%). CONCLUSION: CSHCN with epilepsy, compared to CSHCN without epilepsy, were more likely to have functional difficulties and limitations in school attendance regardless of comorbid conditions.

Use of medication prescribed for emotional or behavioral difficulties among children aged 6-17 years in the United States, 2011-2012.

Mental health problems are common chronic conditions in children (1-3). Medication is often prescribed to treat the symptoms of these conditions (4-7). Few population-based studies have examined the use of prescription medication to treat mental health problems among younger as well as older school-aged children (8-10). This report describes the sociodemographic characteristics of children aged 6-17 years prescribed medication or taking medication during the past 6 months for emotional or behavioral difficulties, and describes parental reports of the perceived benefit of this medication.

Environmental tobacco smoke exposure in children aged 3-19 years with and without asthma in the United States, 1999-2010.

KEY FINDINGS: Data from the National Health and Nutrition Examination Survey, 1999-2010. From 1999 to 2010, the percentage of children without asthma exposed to environmental tobacco smoke (ETS) decreased from 57.3% to 44.2%, while children with asthma showed no change, with 57.9% exposed to ETS in 1999-2002 and 54.0% exposed in 2007-2010. In 2007-2010, a higher percentage of children with asthma were exposed to ETS than children without asthma. In 2007-2010, children with asthma were more likely to be exposed to ETS than children without asthma, if they were girls, Mexican American, aged 6-11 years, or had family income below 350% of the federal poverty guidelines.

National trends in emergency department use of urinalysis, complete blood count, and blood culture for fever without a source among children aged 2 to 24 months in the pneumococcal conjugate vaccine 7 era.

OBJECTIVES: The epidemiology of serious bacterial infections in children has changed since the introduction of the pneumococcal conjugate vaccine (PCV-7) in 2000. Whether emergency department (ED) physicians have changed diagnostic approaches to fever without a source (FWS) in response is unknown. We examine trends in rates of complete blood count (CBC), urinalysis (UA), and blood cultures among 2- to 24-month-old children with FWS since the introduction of PCV-7. METHODS: The National Hospital Ambulatory Medical Care Survey-Emergency Department, 2001-2009, was used to identify visits to the ED by 2- to 24-month-old children with FWS. Rates of CBC, UA, neither CBC nor UA, and blood culture were tracked across time. Trends were identified using Joinpoint regression and bivariate and multivariate logistic regressions with year as the independent variables and ordering of each test as the dependent variables. RESULTS: In bivariate and multivariate analyses, CBC orders declined between 2004 and 2009 for visits by all children 2 to 24 months, children 2 to 11 months, and boys 2 to 24 months (adjusted odds ratio [aOR], 0.88 per year [P < 0.01]; aOR, 0.88 [P < 0.05]; and aOR, 0.83 [P < 0.01], respectively). Between 2004 and 2009, ordering neither CBC nor UA increased among all children 2 to 24 months (aOR, 1.10; P < 0.05) and among boys (aOR, 1.16; P < 0.05). Orders for blood cultures declined across the time period in bivariate analysis, but not in multivariate analysis. CONCLUSIONS: The rate of ordering a CBC for children in the 2- to 24-month age group presenting to the ED with FWS declined, a change coincident with the changing epidemiology of serious bacterial infection since the PCV-7 vaccine was introduced.

Among children with food allergy, do sociodemographic factors and healthcare use differ by severity?

Among children with food allergy, we aim to describe differences in allergy severity by sociodemographic characteristics and potential differences in healthcare characteristics according to food allergy severity. Using the 2007 National Survey of Children's Health, we identified children with food allergies based on parental report (n = 4,657). Food allergic children were classified by the severity of their food allergy, as either mild (n = 2,333) or moderate/severe (n = 2,285). Using logistic regression, we estimated the odds of having moderate/severe versus mild food allergy by sociodemographic characteristics and the odds of having selected healthcare characteristics by food allergy severity. Among children with food allergy, those who were older (ages 6 through 17 years) and those who had siblings were more likely to have moderate/severe allergy compared to their younger and only-child counterparts. There were no significant differences in severity by other sociodemographic characteristics. Children with a moderate/severe food allergy were more likely to report use of an Individual Education Plan (OR = 1.88 [1.31, 2.70]) and to have seen a specialist than those with mild food allergy. Among younger children with food allergy, those with moderate/severe food allergy were more likely to require more services than is usual compared with those with mild allergy. Associations between allergy severity and health care-related variables did not differ significantly by race/ethnicity, income level, or maternal education. We report few differences in allergy severity by sociodemographic characteristics of food allergic children. In addition, we found that associations between allergy severity and use of health related services did not differ significantly by race/ethnicity or poverty status among children with food allergy. Given the importance of food allergy as an emerging public health issue, further research to confirm these findings would be useful.

Clinical sepsis in neonates and young infants, United States, 1988-2006.

OBJECTIVE: To describe the burden and characteristics of clinical neonatal sepsis in the United States and evaluate incidence rates after the issuance of intrapartum antibiotic prophylaxis (IAP) guidelines. STUDY DESIGN: This is a cross-sectional study of hospitalizations of infants aged <3 months diagnosed with sepsis from the 1988-2006 National Hospital Discharge Survey. The National Hospital Discharge Survey collects data annually on inpatient discharges from a national probability sample of approximately 500 short-stay hospitals. We examined sepsis hospitalizations, defined by International Classification of Diseases, Ninth Revision, Clinical Modification codes, and compared sepsis hospitalization rates for 2 time periods after the issuance of IAP guidelines (1996-2001 and 2002-2006) with 1988-1995 using national natality data as the population denominator. We used Joinpoint (Surveillance Research Program, National Cancer Institute, Bethesda, Maryland) regression to assess the average annual percent change (AAPC) in rates. RESULTS: Between 1988 and 2006, there were more than 2.5 million sepsis-related hospitalizations in infants aged <3 months (112 000-146 000 annually). In 2006, the sepsis hospitalization rate was 30.8/1000 births. The rate was more than 3 times higher in preterm infants compared with term infants (85.4/1000 preterm births vs 23.1/1000 term births). The AAPC in sepsis hospitalization rate was -3.6% (95% CI, -5.1% to 2.0%) [corrected] for term infants during 1996-2002 and did not change significantly after issuance of the revised 2002 guidelines. For preterm infants, the AAPC was -1.2% (95% CI, -2.2% to -0.1%) [corrected] annually from 1988 to 2006. CONCLUSION: Clinical neonatal sepsis declined in the post-IAP era, mirroring trends observed in group B streptococcal early-onset neonatal sepsis surveillance. Preterm infants were affected disproportionately and exhibited a modest but steady decline in sepsis hospitalization rate.

Emergency department laboratory evaluations of fever without source in children aged 3 to 36 months.

OBJECTIVE: This article describes ordering of diagnostic tests, admission rates, and antibiotic administration among visits to US emergency departments (EDs) by children aged 3 to 36 months with fever without source (FWS). METHODS: The 2006-2008 National Hospital Ambulatory Medical Care Survey-Emergency Department was used to identify visits by 3- to 36-month-old children with FWS. Percentages of visits that included a complete blood count (CBC), urinalysis, blood culture, radiograph, rapid influenza test, admission to hospital, and ceftriaxone and other antibiotic administration were calculated. Multivariate logistic regression was used to identify factors associated with ordering of a CBC and urinalysis. RESULTS: No tests were ordered in 58.6% of visits for FWS. CBCs were ordered in 20.5% of visits and urinalysis in 17.4% of visits. Even among girls with a temperature of ≥39°C, urinalysis was ordered in only 40.2% of visits. Ceftriaxone was given in 7.1% and other antibiotics in 18.3% of visits; 5.2% of the children at these visits were admitted to the hospital. In multivariate analysis, increased temperature, being female, and higher median income of the patient's zip code were associated with increased odds of having a CBC and urinalysis ordered. Being 24 to 36 months of age was associated with lower odds of receiving both a CBC and a urinalysis. CONCLUSIONS: Most US emergency department visits for FWS among children aged 3 to 36 months, physicians do not order diagnostic tests. Being female, having a higher fever, and higher median income of the patient's zip code were associated with ordering CBCs and urinalysis.

Participation in activities outside of school hours in relation to problem behavior and social skills in middle childhood.

BACKGROUND: Research has shown that participating in activities outside of school hours is associated with lower dropout rates, enhanced school performance, improved social skills, and reduced problem behaviors. However, most prior studies have been limited to small populations of older children (>12 years). This analysis focuses on children aged 6 to 11 to assess the potential association between participation in activities outside of school hours and behavior in middle childhood in a nationally representative survey. METHODS: Estimates were based on 25,797 children from the 2003-2004 National Survey of Children's Health. Outside of school activity was defined as participating in sports teams/lessons, clubs/organizations, or both at least once in the past year. Analysis of variance was used to evaluate the differences in behavior problems and social skills adjusting for sociodemographic factors, among children classified by participation in outside of school activities. RESULTS: Seventy-five percent of children participated in outside of school activities: 23% in sports, 16% in clubs, and 36% in both clubs and sports. Activity participation differed by gender, race/ethnicity, type of school, poverty status, family structure, household education, and school and community safety. Children participating in both sports and clubs had higher social skills index scores, but no significant difference in problem behavior scores compared with children who did not participate in any outside of school activity. CONCLUSION: Children participating in both sports and clubs had greater social competence during middle childhood compared with children who did not participate in any outside of school activities.

Food allergy among children in the United States.

OBJECTIVES: The goals were to estimate the prevalence of food allergy and to describe trends in food allergy prevalence and health care use among US children. METHODS: A cross-sectional survey of data on food allergy among children <18 years of age, as reported in the 1997-2007 National Health Interview Survey, 2005-2006 National Health and Nutrition Examination Survey, 1993-2006 National Hospital Ambulatory Medical Care Survey and National Ambulatory Medical Care Survey, and 1998-2006 National Hospital Discharge Survey, was performed. Reported food allergies, serum immunoglobulin E antibody levels for specific foods, ambulatory care visits, and hospitalizations were assessed. RESULTS: In 2007, 3.9% of US children <18 years of age had reported food allergy. The prevalence of reported food allergy increased 18% (z = 3.4; P < .01) from 1997 through 2007. In 2005-2006, serum immunoglobulin E antibodies to peanut were detectable for an estimated 9% of US children. Ambulatory care visits tripled between 1993 and 2006 (P < .01). From 2003 through 2006, an estimated average of 317000 food allergy-related, ambulatory care visits per year (95% confidence interval: 195000-438000 visits per year) to emergency and outpatient departments and physician's offices were reported. Hospitalizations with any recorded diagnoses related to food allergy also increased between 1998-2000 and 2004-2006, from an average of 2600 discharges per year to 9500 discharges per year (z = 3.4; P < .01), possibly because of increased use of food allergy V codes. CONCLUSION: Several national health surveys indicate that food allergy prevalence and/or awareness has increased among US children in recent years.

Heterogeneity within Asian subgroups: a comparison of birthweight between infants of US and non-US born Asian Indian and Chinese mothers.

OBJECTIVES: Birthweight distributions and proportions of low birthweight (LBW) are commonly used to assess the health of populations. However, the "population" is difficult to define due to differences by race, socioeconomic status, age distribution, and cultural identity. This study analyzes birth outcomes in two Asian subgroups to examine variation within the Asian population. METHODS: Analysis of the 1998-2003 National Center for Health Statistics' natality file for 293,211 singleton births in Asian Indian and Chinese mothers compared birthweight distributions, mean birthweights, proportions of very low birthweight (VLBW) and moderately low birthweight (MLBW) infants, and the influence of maternal nativity on these outcomes. A multiple logistic regression analysis, stratified by maternal nativity, was done to control for established confounders of maternal age, marital status, education, and parity. RESULTS: Maternal characteristics and birthweight distributions varied by race subgroup and nativity. Infants of Asian Indian mothers had a lower mean birthweight and higher proportions of VLBW and MLBW than Chinese. After controlling for differences in maternal characteristics, infants of US born Asian Indian mothers were more likely to be VLBW (AOR 1.87, 95% CI: 1.27-2.75) or MLBW (AOR 1.59, 1.39-1.82) than infants of US born Chinese mothers. Similarly, infants of non-US born Asian Indian mothers were more likely to be VLBW (AOR 2.13, 2.06-2.21) or MLBW (AOR 2.26, 2.18-2.35) then infants of non-US born Chinese mothers. CONCLUSIONS: Our study demonstrates variation in birth outcomes by maternal race and nativity in two Asian subgroups. The heterogeneity within a single commonly used "population" is likely not limited to these two Asian subgroups, but is probably applicable to many populations in the United States. Analyses should try to account for these differences to ensure a more accurate representation of various populations in the US. The difficulty of defining a population by race adds to the complexity of examining disparities in birth outcomes.