Faculty Bibliography

PURPOSE: Safe Routes to School (SRTS) was a federally funded transportation program for facilitating physically active commuting to and from school in children through improvements of the built environment. There is evidence that SRTS programs increase walking and bicycling in school-age children, but their impact on pedestrian and bicyclist safety has not been adequately examined. We investigate the impact and effects of the SRTS program on school-age pedestrian and bicyclist injuries in a nationwide sample in the United States. METHODS: Data were crash records for school-age children (5-19 years) and adults (30-64 years), in 18 U.S. states for a 16-year period (1995-2010). Multilevel negative binomial models were used to examine the association between SRTS intervention and the risk of pedestrian and bicyclist injury in children aged 5-19 years. RESULTS: SRTS was associated with an approximately 23% reduction (incidence rate ratio = 0.77, 95% confidence interval = 0.65-0.92) in pedestrian/bicyclist injury risk and a 20% reduction in pedestrian/bicyclist fatality risk (incidence rate ratio = 0.80, 95% confidence interval = 0.68-0.94) in school-age children compared to adults aged 30-64 years. CONCLUSIONS: Implementation of the SRTS program appears to have contributed to improving traffic safety for school-age children in the United States.

Alcohol use is a risk factor for severe injury in pedestrians struck by motor vehicles. Our objective was to investigate alcohol use by bicyclists and its effects on riding behaviors, medical management, injury severity, and mortality within a congested urban setting. A hospital-based, observational study of injured bicyclists presenting to a Level I regional trauma center in New York City was conducted. Data were collected prospectively from 2012 to 2014 by interviewing all bicyclists presenting within 24 h of injury and supplemented with medical record review. Variables included demographic characteristics, scene-related data, Glasgow Coma Scale (GCS), computed tomography (CT) scans, and clinical outcomes. Alcohol use at the time of injury was determined by history or blood alcohol level (BAL) >0.01 g/dL. Of 689 bicyclists, 585 (84.9%) were male with a mean age of 35.2. One hundred four (15.1%) bicyclists had consumed alcohol prior to injury. Alcohol use was inversely associated with helmet use (16.5% [9.9-25.1] vs. 43.2% [39.1-47.3]). Alcohol-consuming bicyclists were more likely to fall from their bicycles (42.0% [32.2-52.3] vs. 24.2% [20.8-27.9]) and less likely to be injured by collision with a motor vehicle (52.0% [41.7-62.1] vs. 67.5% [63.5-71.3]). 80% of alcohol-consuming bicyclists underwent CT imaging at presentation compared with 51.5% of non-users. Mortality was higher among injured bicyclists who had used alcohol (2.9% [0.6-8.2] vs. 0.0% [0.0-0.6]). Adjusted multivariable analysis revealed that alcohol use was independently associated with more severe injury (Adjusted Odds Ratio 2.27, p = 0.001, 95% Confidence Interval 1.40-3.68). Within a dense urban environment, alcohol use by bicyclists was associated with more severe injury, greater hospital resource use, and higher mortality. As bicycling continues to increase in popularity internationally, it is important to heighten awareness about the risks and consequences of bicycling while under the influence of alcohol.

Coefficient omega and alpha are both measures of the composite reliability for a set of items. Unlike coefficient alpha, coefficient omega remains unbiased with congeneric items with uncorrelated errors. Despite this ability, coefficient omega is not as widely used and cited in the literature as coefficient alpha. Reasons for coefficient omega's underutilization include a limited knowledge of its statistical properties. However, consistent efforts to understand the statistical properties of coefficient omega can help improve its utilization in research efforts. Here, six approaches for estimating confidence intervals for coefficient omega with unidimensional congeneric items were evaluated through a Monte Carlo simulation. The evaluations were made through simulation conditions that mimic realistic conditions that investigators are likely to face in applied work, including items that are not normally distributed and small sample size(s). Overall, the normal theory bootstrap confidence interval had the best performance across all simulation conditions that included sample sizes less than 100. However, most methods had sound coverage with sample sizes of 100 or more.

BACKGROUND:Insulin resistance is associated with microalbuminuria among youth with diabetes mellitus. We sought to determine the dose-response effect of insulin sensitivity (IS) on the magnitude of albuminuria and whether there is a threshold below which urine albumin excretion increases. METHODS:These analyses included participants from the SEARCH for Diabetes in Youth Study with incident diabetes who completed a baseline study visit (n = 2988). We estimated IS using a validated equation incorporating waist circumference, HbA1C, and fasting serum triglycerides. Multivariate regression analyses were performed to assess the effect of IS on urine albumin creatinine ratio (UACR), stratified by diabetes type. The IS threshold was then determined using segmented regressions within each diabetes type and incorporated into the multivariate model. RESULTS:There was an association between IS and UACR in type 2 diabetes only (beta = -0.39; p < 0.001). There was strong statistical evidence for a threshold effect of IS score on UACR in the group of youth with type 2 (beta = 0.40; p < 0.001) but not type 1 diabetes (p = 0.3). CONCLUSIONS:In cross-sectional analyses, there is a negative association between IS and UACR in youth with type 2 but not type 1 diabetes, and this association likely includes a threshold effect of IS on UACR.

Vitamin D and intact parathyroid hormone (iPTH) concentrations differ between individuals of African and European descent and may play a role in observed racial differences in bone mineral density (BMD). These findings suggest that mapping by admixture linkage disequilibrium (MALD) may be informative for identifying genetic variants contributing to these ethnic disparities. Admixture mapping was performed for serum 25-hydroxyvitamin D, 1,25-dihydroxyvitamin D, vitamin D-binding protein (VDBP), bioavailable vitamin D, and iPTH concentrations and computed tomography measured thoracic and lumbar vertebral volumetric BMD in 552 unrelated African Americans with type 2 diabetes from the African American-Diabetes Heart Study. Genotyping was performed using a custom Illumina ancestry informative marker (AIM) panel. For each AIM, the probability of inheriting 0, 1, or 2 copies of a European-derived allele was determined. Non-parametric linkage analysis was performed by testing for association between each AIM using these probabilities among phenotypes, accounting for global ancestry, age, and gender. Fine-mapping of MALD peaks was facilitated by genome-wide association study (GWAS) data. VDBP levels were significantly linked in proximity to the protein coding locus (rs7689609, LOD=11.05). Two loci exhibited significant linkage signals for 1,25-dihydroxyvitamin D on 13q21.2 (rs1622710, LOD=3.20) and 12q13.2 (rs11171526, LOD=3.10). iPTH was significantly linked on 9q31.3 (rs7854368, LOD=3.14). Fine-mapping with GWAS data revealed significant known (rs7041 with VDBP, P=1.38×10(-82)) and novel (rs12741813 and rs10863774 with VDBP, P<6.43×10(-5)) loci with plausible biological roles. Admixture mapping in combination with fine-mapping has focused efforts to identify loci contributing to ethnic differences in vitamin D-related traits.

OBJECTIVE: We aimed to characterize the geographic distribution of post-Hurricane Sandy emergency department use in administrative flood evacuation zones of New York City. METHODS: Using emergency claims data, we identified significant deviations in emergency department use after Hurricane Sandy. Using time-series analysis, we analyzed the frequency of visits for specific conditions and comorbidities to identify medically vulnerable populations who developed acute postdisaster medical needs. RESULTS: We found statistically significant decreases in overall post-Sandy emergency department use in New York City but increased utilization in the most vulnerable evacuation zone. In addition to dialysis- and ventilator-dependent patients, we identified that patients who were elderly or homeless or who had diabetes, dementia, cardiac conditions, limitations in mobility, or drug dependence were more likely to visit emergency departments after Hurricane Sandy. Furthermore, patients were more likely to develop drug-resistant infections, require isolation, and present for hypothermia, environmental exposures, or administrative reasons. CONCLUSIONS: Our study identified high-risk populations who developed acute medical and social needs in specific geographic areas after Hurricane Sandy. Our findings can inform coherent and targeted responses to disasters. Early identification of medically vulnerable populations can help to map "hot spots" requiring additional medical and social attention and prioritize resources for areas most impacted by disasters. (Disaster Med Public Health Preparedness. 2016;page 1 of 11).

BACKGROUND: Geographic variation in healthcare has been traditionally studied in large areas such as hospital referral regions or service areas. These analyses are limited by variation that exists within local communities. MATERIALS AND METHODS: Using a New York claims database, we analyzed variation in emergency department use using 35 million visits from 2008 to 2012 among 4797 Census tracts, a smaller unit than usually studied. Using multivariate analysis, we studied associations between population characteristics and proximity to healthcare with rates of emergency department use. We analyzed how factors associated with emergency department utilization differed among urban, suburban, and rural regions. RESULTS: We found significant geographic variation in emergency department use among Census tracts. Public insurance and uninsurance were correlated with high emergency department utilization across all types of regions. We found that race, ethnicity, and poverty were only associated with high emergency department use in urban regions. In suburban and rural regions, a lower proportion of elderly residents and shorter distances to the nearest ED were correlated with high emergency department use. CONCLUSIONS: Significant variation in emergency department use exists locally when studied within small geographic areas. Insurance type is significantly associated with variation in emergency department use across urban, suburban, and rural regions, whereas the significance of other factors depended on urbanicity. IMPLICATIONS: Studying geographic variation at a more granular level can lead to better understanding of local population health, drivers of healthcare utilization, and inform targeted interventions. Given heterogeneity in emergency department use by Census tract, policies directed at shaping acute care utilization must consider these local geographic differences.

Homelessness and housing instability is a significant public health problem among young sexual minority men. While there is a growing body of literature on correlates of homelessness among sexual minority men, there is a lack of literature parsing the different facets of housing instability. The present study examines factors associated with both living and sleeping in unstable housing among n = 600 sexual minority men (ages 18-19). Multivariate models were constructed to examine the extent to which sociodemographic, interpersonal, and behavioral factors as well as adverse childhood experiences explain housing instability. Overall, 13 % of participants reported sleeping in unstable housing and 18 % had lived in unstable housing at some point in the 6 months preceding the assessment. The odds of currently sleeping in unstable housing were greater among those who experienced more frequent lack of basic needs (food, proper hygiene, clothing) during their childhoods. More frequent experiences of childhood physical abuse and a history of arrest were associated with currently living in unstable housing. Current enrollment in school was a protective factor with both living and sleeping in unstable housing. These findings indicate that being unstably housed can be rooted in early life experiences and suggest a point of intervention that may prevent unstable housing among sexual minority men.

BACKGROUND: Fine particulate matter (PM2.5) air pollution exposure has been identified as a global health threat. However, the types and sources of particles most responsible are not yet known. In this work, we sought to identify the causal characteristics and sources of air pollution underlying past published associations in the American Cancer Society's Cancer Prevention Study-II cohort between long-term PM2.5 exposure and Ischemic Heart Disease (IHD) mortality. METHODS: Individual risk factor data were evaluated for 445,860 adults in 100 U.S. metropolitan areas followed from 1982 to 2004 for vital status and cause of death. Using Cox proportional hazard models, IHD mortality hazard ratios (HRs) were derived for PM2.5, trace constituents, and pollution source-associated PM2.5, as derived from air monitoring at central stations throughout the nation during 2000-2005. RESULTS: Associations with IHD mortality varied by PM2.5 mass constituent and source. A coal combustion PM2.5 IHD HR = 1.05 (95% CI=1.02, 1.08) per microg/m3, versus an IHD HR = 1.01 (95% CI=1.00, 1.02) per microg/m3 PM2.5 mass, indicated a risk roughly five times higher for coal combustion PM2.5 than for PM2.5 mass in general, on a per microg/m3 PM2.5 basis. Diesel traffic-related elemental carbon (EC) soot was also associated with IHD mortality (HR = 1.03; 95% CI: 1.00, 1.06 per 0.26 mug/m3 EC increase). However, PM2.5 from both wind-blown soil and biomass combustion were not associated with IHD mortality. CONCLUSIONS: Long-term PM2.5 exposures from fossil fuel combustion, especially coal burning, but also from diesel traffic, were associated with increases in IHD mortality in this nationwide population. Results suggest that PM2.5 - mortality associations can vary greatly by source, and that the largest IHD health benefits per microg/m3 from PM2.5 air pollution control may be achieved via reductions of fossil fuel combustion exposures, especially from coal-burning sources.

BACKGROUND: Dietary composition has been associated with sleep indexes. However, most of the evidence is based on cross-sectional data, and studies in young children are lacking. OBJECTIVE: The aim of this study was to explore the longitudinal associations of macronutrient composition of the diet with sleep duration and consolidation (number of awakenings) in infancy and early childhood. METHODS: The study was performed in 3465 children from the Generation R Study, a population-based cohort study in the Netherlands. Mothers reported their child's food intake at 13 mo of age by using a validated food-frequency questionnaire and their child's sleep patterns at 2 and 3 y of age. We used nutrient substitution models to assess the associations of relative macronutrient intakes with sleep indexes and adjusted the models for sociodemographic and lifestyle factors. RESULTS: Isocaloric substitution of fat intake by protein or carbohydrate in infancy was associated with longer total sleep duration at 2 but not 3 y of age. For each 5% increase in energy intake of either protein or carbohydrate at the expense of fat, sleep duration at 2 y of age was longer by 6 min (95% CI: 0.4, 12 min) and 4 min (95% CI: 2, 6 min), respectively. Further exploration of macronutrient subtypes indicated no consistent differences between saturated or unsaturated fat and that intake of plant compared with animal protein or Trp did not explain the association of higher total protein intake with longer sleep duration at 2 y of age. Replacing unsaturated with saturated fat was associated with 7 min (95% CI: -13, -1 min) shorter total sleep duration at 3 y of age. Macronutrient intakes were not associated with sleep consolidation. CONCLUSIONS: Our results suggest that the macronutrient composition of the diet is associated with sleep duration in young children. Future research should further study the causality of this association and explore the underlying mechanisms.