Population density: What does it really mean in geographical health studies?

Population density is an indicator in many studies, but often with only a cursory explanation of why. Unfortunately, elected officials and the media draw misleading conclusions about population density and public health. After providing three reasons why population density is linked to human health outcomes, using state, county, municipal and neighborhood scale data, we show that population density serves as a surrogate for explaining the geographical distribution of life expectancy and broadband access. However, population density loses its unique contribution when other factors influencing health are included. We urge authors to explain why they include population density in their studies.

Incidence of Severe Maternal Morbidity During Delivery Hospitalization in U.S. Commercially Insured and Medicaid Populations.

Objective: To estimate the incidence rate and associated risk factors of severe maternal morbidity (SMM) in commercially and Medicaid-insured women. Materials and Methods: This was a retrospective cohort study of women with a live inpatient delivery recorded in 2016 in the MarketScan® databases for commercially insured and Medicaid populations. The incidence of SMM, defined by the Center for Disease Control and Prevention's algorithm of International Classification of Diseases, 10th edition diagnostic and procedural codes, was determined. Measurements also included the association of SMM in bivariate analyses with patient characteristics and the association of SMM with delivery type, gestation type, maternal age, and race in multivariate logistic regression analysis, adjusted for pre-existing conditions and pregnancy-related complications. Results: The incidence of SMM per 10,000 deliveries was 111.4 in the Commercial and 109.6 in the Medicaid population. The most frequent SMM indicators were eclampsia and blood transfusion in the Commercial population (35.0 and 25.7 per 10,000 deliveries, respectively) and eclampsia and adult respiratory distress syndrome in the Medicaid population (45.5 and 14.9 per 10,000 deliveries, respectively). A cesarean delivery was associated with SMM in both Commercial (odds ratio [OR] 3.37; 95% confidence interval [CI] 1.51-1.84) and Medicaid populations (OR 1.99; 95% CI 1.80-2.17). A multifetal gestation was also associated with SMM in both Commercial (OR 3.37; 95% CI 2.80-4.10) and Medicaid populations (OR 2.26; 95% CI 1.86-2.75). Conclusion: SMM occurred in 1.1% of live inpatient deliveries. A cesarean delivery, multifetal gestation, race, region, and several pre-existing comorbidities and obstetric complications were associated with SMM.

Costs of Severe Maternal Morbidity in U.S. Commercially Insured and Medicaid Populations: An Updated Analysis.

Background: The most common reason for hospitalization in the United States is childbirth. The costs of childbirth are substantial. Materials and Methods: This was a retrospective cohort study of hospital deliveries identified in the MarketScan® Commercial and Medicaid health insurance claim databases. Women with an inpatient birth in the calendar year 2016 were included. Severe maternal morbidity (SMM) was identified using the Centers for Disease Control and Prevention algorithm of 21 International Classification of Diseases-10 codes. Mean costs and cost ratios for women with and without SMM were reported. Generalized linear models were used to analyze demographic and clinical variables influencing delivery costs. Results: We identified 1,486 women in the Commercial population, who had a birth in 2016 and met the criteria for SMM. The total mean per-patient costs of care for women with and without SMM were $50,212 and $23,795, respectively. In the Medicaid population there were 29,763 births, of which 342 met the criteria for SMM. The total mean per-patient costs of care for women with and without SMM were $26,513 and $9,652, respectively. A multifetal gestation, a cesarean delivery, maternal age, and pregnancy-related complications were independently predictive of increased delivery costs in both Commercial and Medicaid populations. Conclusions: The occurrence of SMM was associated with an increase in maternity-related costs of 111% in the Commercial and 175% in the Medicaid population. Some of the factors associated with increased delivery hospitalization costs could be treated or avoided.

Hospital Readmission Following Delivery With and Without Severe Maternal Morbidity.

Background: The relationship between severe maternal morbidity (SMM) events during inpatient delivery and subsequent hospital readmission is not well understood. Materials and Methods: This was a retrospective cohort study of women with a live inpatient delivery during 2016 recorded in MarketScan® databases for commercially insured and Medicaid populations. Live inpatient births were identified by the International Classification of Diseases, 10th Revision diagnostic and procedural codes, Current Procedural Terminology, and Diagnosis-Related Group codes. The incidence of hospital readmission within 30 days following a delivery discharge, and primary discharge diagnoses, were determined by SMM status. The association with hospital readmission of SMM status, delivery type, gestation type, and maternal age was determined in multivariable logistic regression analyses, adjusted for pregnancy-related complications and preexisting comorbidities. Results: In the Commercial population there were 1,927 hospital readmissions, for an incidence rate of 11.7 per 1,000 discharges. The readmission rate was 12 times greater for women with SMM than for women without SMM during delivery. The most frequent discharge diagnoses among women readmitted were other complications of the puerperium, endometritis, and infection of obstetric surgical wound of women without SMM during delivery. In multivariable analysis, SMM during delivery was strongly associated with readmission in the Commercial population. Results for the Medicaid population were similar. Conclusion: SMM during delivery hospitalization increased the risk of readmission more than 10 times. The most frequent discharge diagnoses following readmission included obstetric infection and endometritis in women without SMM, and eclampsia in women with SMM during delivery. Awareness of these findings could help health care providers prevent future episodes.

Risk factors for acute stroke among South Asians compared to other racial/ethnic groups.

BACKGROUND: Studies of racial/ethnic variations in stroke rarely consider the South Asian population, one of the fastest growing sub-groups in the United States. This study compared risk factors for stroke among South Asians with those for whites, African-Americans, and Hispanics. METHODS: Data on 3290 stroke patients were analyzed to examine risk differences among the four racial/ethnic groups. Data on 3290 patients admitted to a regional stroke center were analyzed to examine risk differences for ischemic stroke (including subtypes of small and large vessel disease) among South Asians, whites, African Americans and Hispanics. RESULTS: South Asians were younger and had higher rates of diabetes mellitus, blood pressure, and fasting blood glucose levels than other race/ethnicities. Prevalence of diabetic and antiplatelet medication use, as well as the incidence of small-artery occlusion ischemic stroke was also higher among South Asians. South Asians were almost a decade younger and had comparable socioeconomic levels as whites; however, their stroke risk factors were comparable to that of African Americans and Hispanics. DISCUSSION: Observed differences in stroke may be explained by dietary and life style choices of South Asian-Americans, risk factors that are potentially modifiable. Future population and epidemiologic studies should consider growing ethnic minority groups in the examination of the nature, outcome, and medical care profiles of stroke.

Lipid profiles and ischemic stroke risk: variations by sex within racial/ethnic groups.

Evidence implicates lipid abnormalities as important but modifiable risk factors for stroke. This study assesses whether hypercholesterolemia can be used to predict the risk for etiologic subtypes of ischemic stroke between sexes within racial/ethnic groups. Data elements related to stroke risk, diagnosis, and outcomes were abstracted from the medical records of 3,290 acute stroke admissions between 2006 and 2010 at a regional stroke center. Sex comparison within racial/ethnic groups revealed that South Asian and Hispanic men had a higher proportion of ischemic stroke than women, while the inverse was true for Whites and African Americans (P=0.0014). All women, except South Asian women, had higher mean plasma total cholesterol and higher blood circulating low-density lipoprotein levels (≥100 mg/dL) than men at the time of their admissions. The incidence of large-artery atherosclerosis (LAA) was more common among women than men, except among Hispanics, where men tended to have higher incidences. A regression analysis that considered patients diagnosed with either LAA or small-artery occlusion etiologic subtype as the outcomes and high-density lipoproteins and triglycerides as predictors showed inconsistent associations between lipid profiles and the incidence of these subtypes between the sexes within racial/ethnic groups. In conclusion, our investigation suggests that women stroke patients may be at increased risk for stroke etiologic subtype LAA than men. Although the higher prevalence of stroke risk factors examined in this study predicts the increase in the incidence of the disease, lack of knowledge/awareness and lack of affordable treatments for stroke risk factors among women and immigrants/non-US-born subpopulations may explain the observed associations.

Disparities in acute stroke severity, outcomes, and care relative to health insurance status.

BACKGROUND: To examine the differences in risk factors and length of hospital stay (LOS) between the insured and uninsured stroke patients, identifying the root causes of increasing hospital stay. METHODS: Retrospective analysis of stroke registry data of acute stroke patients (N = 19,255) was analyzed to compare risk factors, severity, outcome, and LOS by insurance status. Chart review of patients from a comprehensive stroke center (N = 3290) was studied in greater detail for causes of extended length of stay. RESULTS: The uninsured patients had poorer control of risk factors and statistically significantly (P < .0001) higher initial stroke severity, mortality, and LOS as compared with insured patients (3.8 versus 4.5 days, respectively). The increased length of stay was largely accounted for by the inability to transfer uninsured patients to inpatient rehabilitation settings. CONCLUSION: This study highlights the need for public policies that provide funding for both primary stroke prevention and poststroke rehabilitation.

The relationship between temperament, gender, and childhood dysfunctional voiding.

OBJECTIVE: Dysfunctional voiding (DV) is an extremely common pediatric complaint. The goal of this study was to examine the relationship between DV and childhood temperament. METHODS: Information about the voiding behaviors and temperaments of 50 children was examined using a case-control model. Caregivers were asked to fill out the Children's Behavior Questionnaire in order to rate their child on the dimensions of surgency, negative affect, and effortful control. The relationship between DV and these dimensions was then evaluated. RESULTS: Males with DV were found to have lower effortful control than males with normal voiding habits. Females with DV did not demonstrate a difference in effortful control, but did demonstrate a higher rate of surgency. CONCLUSIONS: The results suggest that temperament does have an association with DV. These findings are in line with temperamental associations with other externalizing trouble behaviors and may inform potential treatment strategies for DV.

Urinary dysfunction in children is associated with exposure to environmental tobacco smoke.

OBJECTIVE: Environmental tobacco smoke (ETS) is known to cause significant morbidity across a wide variety of organ systems. The purpose of this study was to examine the relationship of ETS exposure with pediatric urinary dysfunction. PATIENTS AND METHODS: Participants were drawn from a university-based pediatric urology practice throughout the first half of 2011. All patients who presented with a chief complaint of urinary dysfunction were approached to participate (N = 184). Exclusion criteria eliminated all but 71 subjects. Of these, 68 subjects and their parents completed age-appropriate questionnaires on ETS exposure and symptom severity. Data were analyzed using descriptive statistics and relationship between exposure and outcome was evaluated via Spearman correlation analysis. RESULTS: A total of 68 children with no known etiology for their urinary dysfunction were evaluated for symptom severity and ETS exposure. Participants demonstrated a significant positive correlation (rho = 0.592 for those 4-10 years; rho = 0.415 for those 11-17 years) between ETS exposure and severity of their urinary symptoms. CONCLUSIONS: These data indicate a positive relationship between ETS exposure and urinary dysfunction among children with no other obvious etiology for their symptoms. Physicians should inform parents of the potential dangers of childhood ETS exposure, including the possible relationship with urinary dysfunction.

Toilet training method is not related to dysfunctional voiding.

BACKGROUND: Toilet training is an important marker of physical and psychosocial development, but the best strategy for implementing training is still unknown. The purpose of this study is to compare dysfunctional voiding outcomes for 2 common toilet training strategies: parent-oriented training and child-oriented training. MATERIALS AND METHODS: This study was completed using a case-control design, with participants between the ages of 4 and 12 years. All participants were asked to complete questionnaires related to demographics and toilet training method. Results were then analyzed between cases and controls. RESULTS: In all, 215 patients with a mean age 7.76 years participated in this study. Cases and controls showed no significant difference for demographic measures and socioeconomic status. Furthermore, there was no significant difference in dysfunctional voiding between toilet training methods. CONCLUSION: Toilet training method does not seem to have any long-term effect on dysfunctional voiding. As such, clinicians should advise parents that both methods are acceptable.

Evaluation of consistency between physician clinical impression and 3 validated survey instruments for measuring lower urinary tract symptoms in children.

PURPOSE: Since many children with lower urinary tract symptoms are treated based on history and physical, it is important to know which symptom survey correlates best with the physician clinical impression. We evaluated 3 tools that have been demonstrated to predict severity of lower urinary tract symptoms, the Dysfunctional Voiding Symptom Score, the Akbal survey and the Nelson survey. Total scores from each survey were compared to clinical impression. MATERIALS AND METHODS: Participants consisted of 36 males and 35 females referred to our pediatric urology center for lower urinary tract symptoms. A total of 37 children 4 to 10 years old completed the Dysfunctional Voiding Symptom Score with the help of their parents, and 34 of these parents completed the Akbal survey. A total of 35 children 11 to 17 years old completed the Nelson survey. Scores from the 3 instruments were compared to the clinical impression of a pediatric urologist using rank correlation (Kendall's tau-b test). RESULTS: Mean total symptom scores were increased relative to physician rating for all 3 surveys. Symptoms reported by younger children using the Dysfunctional Voiding Symptom Score correlated better with physician rating of symptom severity (tau-b 0.43) compared to symptoms reported by parents using the Akbal survey (tau-b 0.41). Older children reporting symptoms using the Nelson survey had the strongest correlation with physician clinical impression (tau-b 0.48). CONCLUSIONS: All 3 surveys were statistically significantly correlated with the physician impression of severity for lower urinary tract symptoms, with the Nelson survey being the most accurate.

Advising the newest faces of public health: a perspective on the undergraduate student.

In the 20th century, public health education in the United States existed as a professional degree program, with training at the masters (MPH) and doctoral (PhD, DrPH, and ScD) levels. Today, the system is rapidly evolving as undergraduate majors, minors, and concentrations are establishing themselves around the country. This new focus of public health education, rooted in a liberal arts environment, is distinct from the professional training of graduate school. As such, undergraduate public health students have unique characteristics and needs that should be considered as part of the advisors' responsibility to provide meaningful, relevant advising. The perspective and comments presented here are largely based on the authors' nearly 30 years of combined experience in undergraduate public health education.

Later toilet training is associated with urge incontinence in children.

OBJECTIVE: The objective of this study was to determine if later toilet training is associated with urge incontinence in children. METHODS: We used a case-control study design to yield level 2 evidence. RESULTS: Initiation of toilet training after 32 months of age was associated with urge incontinence (P=0.02). CONCLUSION: For children who display signs of toilet-training readiness, training should be initiated prior to 32 months of age to reduce the risk for urge incontinence.

Nocturnal enuresis and overweight are associated with obstructive sleep apnea.

OBJECTIVE: The objective of this study was to examine the relationship of obstructive sleep apnea (OSA), body weight (BMI percentage [BMI%]), and monosymptomatic nocturnal enuresis (MNE) in children. METHODS: A case-control study design was used. All children were 5 to 15 years of age; case patients were recruited from a comprehensive sleep disorders center (n = 149), and control subjects were recruited from a general pediatric practice in the same catchment area (n = 139). Case patients were subject to overnight polysomnograms and grouped into apnea severity categories (minimal, mild, moderate, or severe) on the basis of respiratory disturbance index and minimum arterial oxygen saturation levels. Data for all children included age; gender; height; weight; and history of MNE, snoring, diabetes, nasal allergies, and/or enlarged tonsils. BMI% was used to group children into weight categories as suggested by the Centers for Disease Control and Prevention (underweight, normal weight, at risk for overweight, and overweight). Two age groupings were created (5-10 years and 11-15 years). Descriptive statistics provided the prevalence of OSA, weight category, and MNE among case patients and control subjects. Cross-tabulations examined the relationship of severity of OSA with weight categories and MNE, stratified by age and gender. A series of logistic regression models explored the interrelationship of the grouping variables. RESULTS: A large majority (79.9%) of control subjects were at risk for overweight, and a large majority (80.0%) of children with MNE also had some degree of OSA. Logistic regression demonstrated that both MNE (odds ratio: 5.29) and overweight (odds ratio 4.16) were significantly associated with OSA but not with each other. CONCLUSIONS: Overweight and MNE are associated with OSA but not with each other. OSA should be considered in overweight children with MNE, especially when they display other symptoms of OSA or fail to respond to standard MNE treatment programs.

Building and sustaining a multiuniversity and multicampus program or school of public health.

Drawing from New Jersey's successful efforts and from other less successful efforts, we offer lessons learned for those who will consider a multiuniversity and multi-campus program or school of public health. These lessons include building a faculty collaboration, senior administrative support, and external constituencies and developing a set of documents that institutionalize processes, logistics, and other operations. In our experience, building and sustaining faculty support is the greatest challenge, followed by protecting existing resources and securing additional resources when administrators in the host universities change.

Seed grants as a means of stimulating cancer research funding.

OBJECTIVES: Seed grant programs have been suggested as an innovative way to launch new initiatives. We evaluated one such program designed to stimulate cancer research in a state with little to moderate cancer research activity. Success was defined as the ability of seed grant recipients to develop proposals, obtain external funding and publish the results of cancer-related research. METHODS: Data were collected through the Internet from a variety of funding and publication databases, as well as through updated curriculum vitae and a mail survey of the seed grant recipients. RESULTS: Fifteen (31%) experienced investigators and 33 (69%) new investigators credited their seed grants with helping them leverage 60 active research grants and 10 pending proposals with a variety of funders. Overall, seed grant recipients leveraged $10.10 for every dollar of seed grant funding they received. Anecdotal evidence showed that seed grants allowed grantees to establish themselves as legitimate cancer research investigators, develop and fund their laboratories, and focus or refocus their work. These results are from a single case study. CONCLUSIONS: Seed grants for pilot projects inexpensively and efficiently built cancer research capacity in a state with historically low levels of national cancer research funding. As our findings are based on a single case study, we cannot state that this strategy would succeed for other states in similar circumstances.

Breastfeeding during infancy may protect against bed-wetting during childhood.

OBJECTIVE: Our goal was to test the hypothesis that children who exhibit bed-wetting during childhood were less likely to be breastfed during infancy compared with normal controls. METHODS: A case-control study was conducted in a pediatric continence center and a general pediatric practice. Cases (n = 55) were recruited from the continence center and defined as children 5 to 13 years of age who experienced lifetime involuntary voiding of urine during nighttime sleep at least 2 times a week in the absence of defects of the central nervous system or urinary tract. Age- and gender-matched controls (n = 117) who did not exhibit bed-wetting were enrolled from a general pediatric practice. Infant feeding practices were measured as breastfeeding (yes/no) and, for those who were breastfeed, by the duration of breastfeeding and the time of formula supplementation. RESULTS: Among the case subjects, 45.5% were breastfed, whereas among the controls 81.2% were breastfed. The controls reported higher household incomes than the case subjects, and their mean family size (number of children) was slightly lower. After adjusting for race, income, and family size, the odds ratio was 0.283, indicating that case subjects were significantly less likely than controls to be breastfeed. Among all the study subjects who were breastfed, controls were breastfed for a significantly longer period than case subjects (an average of 3 months longer). Although breastfed controls were less likely to be supplemented with formula than breastfed case subjects, this difference was not statistically significant. CONCLUSIONS: Breastfeeding longer than 3 months may protect against bed-wetting during childhood. Breast milk supplemented with formula did not make a difference in the rate of enuresis.

A retrospective occupational cohort study of end-stage renal disease in aircraft workers exposed to trichloroethylene and other hydrocarbons.

OBJECTIVE: Case-control studies suggest hydrocarbons increase end-stage renal disease (ESRD) risk. No cohort studies have been conducted. METHODS: An occupational database was matched to the U.S. Renal Data System, and the outcome of all-cause ESRD was examined using multivariable Cox regression. Sixteen individual hydrocarbons were studied, although exposures were not mutually exclusive. RESULTS: For the 1973-2000 period, there was an approximate twofold increased risk of ESRD among workers exposed to trichloroethylene, 1,1,1-trichloroethane, and JP4 gasoline compared with unexposed subjects (all P < 0.05). Relative risk was greater than unity (P > 0.05) for several other hydrocarbons. Associations attenuated (all P > 0.05) when 2001-2002 data were included in the analyses. CONCLUSIONS: Certain hydrocarbons may increase all-cause ESRD risk. Uncertainty regarding the mechanism for increased risk and the observed attenuation in risk in 2001-2002, as well as the overlap of exposures, complicates interpretation. Additional research is needed.

The epidemiology of pulmonary embolism: racial contrasts in incidence and in-hospital case fatality.

Mortality from pulmonary embolism (PE) has declined in the United States over the past two decades, yet significant racia l disparities persist with the age-adjusted rates for blacks about twice those for whites. Incidence studies to date have not been successful in defining reasons for this disparity, primarily because they have not enrolled sufficient numbers of blacks to allow for racial comparisons. This study overcomes that limitation by using New Jersey hospital discharge data as a surrogate measure for PE incidence. It examines whether differences in access to care, in-hospital case fatality, discharge planning or other factors might help explain the observed patterns. Our results revealed an elevation in the incidence of PE among blacks compared with whites, similar to the contrasts in mortality. In-hospital case fatality did not differ notably between blacks and whites, indicating that treatment in-hospital is an unlikely contributing factor. We found differences in hospital discharge planning and insurance status, suggesting that these factors may play a role. Our results point to the need for longitudinal studies on the natural history of the disease to better identify and hopefully modify the risk factors responsible for the persistent disparity in mortality from PE.