Efficacy of Low-Cost Sensor Networks at Detecting Fine-Scale Variations in Particulate Matter in Urban Environments.

The negative health impacts of air pollution are well documented. Not as well-documented, however, is how particulate matter varies at the hyper-local scale, and the role that proximal sources play in influencing neighborhood-scale patterns. We examined PM2.5 variations in one airshed within Indianapolis (Indianapolis, IN, USA) by utilizing data from 25 active PurpleAir (PA) sensors involving citizen scientists who hosted all but one unit (the control), as well as one EPA monitor. PA sensors report live measurements of PM2.5 on a crowd sourced map. After calibrating the data utilizing relative humidity and testing it against a mobile air-quality unit and an EPA monitor, we analyzed PM2.5 with meteorological data, tree canopy coverage, land use, and various census variables. Greater proximal tree canopy coverage was related to lower PM2.5 concentrations, which translates to greater health benefits. A 1% increase in tree canopy at the census tract level, a boundary delineated by the US Census Bureau, results in a ~0.12 µg/m3 decrease in PM2.5, and a 1% increase in "heavy industry" results in a 0.07 µg/m3 increase in PM2.5 concentrations. Although the overall results from these 25 sites are within the annual ranges established by the EPA, they reveal substantial variations that reinforce the value of hyper-local sensing technologies as a powerful surveillance tool.

Pembrolizumab Induced Acute Persistent Airway Disease in a Patient with Recurrent Respiratory Papillomatosis (RRP).

OBJECTIVE: To present an uncommon but serious, recently identified complication of checkpoint inhibitor therapy in a patient treated with pembrolizumab infusion for disseminated recurrent respiratory papillomatosis (RRP). METHODS: Case report. RESULTS: A 43-year-old woman with underlying asthma developed acute hypoxic respiratory failure within 24 hours of her third infusion of pembrolizumab for treatment of intractable, disseminated recurrent respiratory papillomatosis. Pulmonary function testing revealed a severe intra-thoracic obstructive ventilatory defect. Discontinuation of pembrolizumab, ventilatory support, and treatment with systemic and inhaled corticosteroids resulted in resolution of respiratory failure; however, her underlying asthma remains poorly controlled. CONCLUSION: To our knowledge, this case is the first report of pembrolizumab-induced obstructive respiratory failure in a patient being treated for RRP.

Factorial Invariance of the Abbreviated Neighborhood Environment Walkability Scale among Senior Women in the Nurses' Health Study Cohort.

The purpose of this study was to examine the factorial invariance of the Abbreviated Neighborhood Environment Walkability Scale (NEWS-A) across subgroups based on demographic, health-related, behavioral, and environmental characteristics among Nurses' Health Study participants (N = 2,919; age M = 73.0, SD = 6.9 years) living in California, Massachusetts, and Pennsylvania. A series of multi-group confirmatory factor analyses were conducted to evaluate increasingly restrictive hypotheses of factorial invariance. Factorial invariance was supported across age, walking limitations, and neighborhood walking. Only partial scalar invariance was supported across state residence and neighborhood population density. This evidence provides support for using the NEWS-A with older women of different ages, who have different degrees of walking limitations, and who engage in different amounts of neighborhood walking. Partial scalar invariance suggests that researchers should be cautious when using the NEWS-A to compare older adults living in different states and neighborhoods with different levels of population density.

Accelerometer and GPS Data to Analyze Built Environments and Physical Activity.

Purpose: Most built environment studies have quantified characteristics of the areas around participants' homes. However, the environmental exposures for physical activity (PA) are spatially dynamic rather than static. Thus, merged accelerometer and global positioning system (GPS) data were utilized to estimate associations between the built environment and PA among adults. Methods: Participants (N = 142) were recruited on trails in Massachusetts and wore an accelerometer and GPS unit for 1-4 days. Two binary outcomes were created: moderate-to-vigorous PA (MVPA vs. light PA-to-sedentary); and light-to-vigorous PA (LVPA vs. sedentary). Five built environment variables were created within 50-meter buffers around GPS points: population density, street density, land use mix (LUM), greenness, and walkability index. Generalized linear mixed models were fit to examine associations between environmental variables and both outcomes, adjusting for demographic covariates. Results: Overall, in the fully adjusted models, greenness was positively associated with MVPA and LVPA (odds ratios [ORs] = 1.15, 95% confidence interval [CI] = 1.03, 1.30 and 1.25, 95% CI = 1.12, 1.41, respectively). In contrast, street density and LUM were negatively associated with MVPA (ORs = 0.69, 95% CI = 0.67, 0.71 and 0.87, 95% CI = 0.78, 0.97, respectively) and LVPA (ORs = 0.79, 95% CI = 0.77, 0.81 and 0.81, 95% CI = 0.74, 0.90, respectively). Negative associations of population density and walkability with both outcomes reached statistical significance, yet the effect sizes were small. Conclusions: Concurrent monitoring of activity with accelerometers and GPS units allowed us to investigate relationships between objectively measured built environment around GPS points and minute-by-minute PA. Negative relationships between street density and LUM and PA contrast evidence from most built environment studies in adults. However, direct comparisons should be made with caution since most previous studies have focused on spatially fixed buffers around home locations, rather than the precise locations where PA occurs.

Accelerometer and GPS Analysis of Trail Use and Associations With Physical Activity.

BACKGROUND: Concurrent use of accelerometers and global positioning system (GPS) data can be used to quantify physical activity (PA) occurring on trails. This study examined associations of trail use with PA and sedentary behavior (SB) and quantified on trail PA using a combination of accelerometer and GPS data. METHODS: Adults (N = 142) wore accelerometer and GPS units for 1-4 days. Trail use was defined as a minimum of 2 consecutive minutes occurring on a trail, based on GPS data. We examined associations between trail use and PA and SB. On trail minutes of light-intensity, moderate-intensity, and vigorous-intensity PA, and SB were quantified in 2 ways, using accelerometer counts only and with a combination of GPS speed and accelerometer data. RESULTS: Trail use was positively associated with total PA, moderate-intensity PA, and light-intensity PA (P < .05). On trail vigorous-intensity PA minutes were 346% higher when classified with the combination versus accelerometer only. Light-intensity PA, moderate-intensity PA, and SB minutes were 15%, 91%, and 85% lower with the combination, respectively. CONCLUSIONS: Adult trail users accumulated more PA on trail use days than on nontrail use days, indicating the importance of these facilities for supporting regular PA. The combination of GPS and accelerometer data for quantifying on trail activity may be more accurate than accelerometer data alone and is useful for classifying intensity of activities such as bicycling.

The built environment predicts observed physical activity.

BACKGROUND: In order to improve our understanding of the relationship between the built environment and physical activity, it is important to identify associations between specific geographic characteristics and physical activity behaviors. PURPOSE: Examine relationships between observed physical activity behavior and measures of the built environment collected on 291 street segments in Indianapolis and St. Louis. METHODS: Street segments were selected using a stratified geographic sampling design to ensure representation of neighborhoods with different land use and socioeconomic characteristics. Characteristics of the built environment on-street segments were audited using two methods: in-person field audits and audits based on interpretation of Google Street View imagery with each method blinded to results from the other. Segments were dichotomized as having a particular characteristic (e.g., sidewalk present or not) based on the two auditing methods separately. Counts of individuals engaged in different forms of physical activity on each segment were assessed using direct observation. Non-parametric statistics were used to compare counts of physically active individuals on each segment with built environment characteristic. RESULTS: Counts of individuals engaged in physical activity were significantly higher on segments with mixed land use or all non-residential land use, and on segments with pedestrian infrastructure (e.g., crosswalks and sidewalks) and public transit. CONCLUSION: Several micro-level built environment characteristics were associated with physical activity. These data provide support for theories that suggest changing the built environment and related policies may encourage more physical activity.

Noninvasive positive pressure ventilation in subjects with stable COPD: a randomized trial.

BACKGROUND: The use of domiciliary noninvasive positive pressure ventilation (NPPV) in stable chronic obstructive pulmonary disease (COPD) with chronic hypercapnic respiratory failure has yielded variable effects on survival, quality of life, and dyspnea. We hypothesized that use of NPPV in stable COPD and partial pressure of carbon dioxide (PaCO2) <52 mmHg might result in improvement in quality of life and dyspnea. METHODS: Thirty patients with stable COPD (forced expiratory volume in the first second <50% predicted and PaCO2 <52 mmHg) were prospectively randomized to receive domiciliary NPPV (bilevel positive airway pressure, 15/5 cm H2O) or usual therapy for 6 months. Measurements were made at baseline, 6 weeks, 3 months, and 6 months. Primary outcomes were quality of life as assessed by the Chronic Respiratory Disease Questionnaire (CRQ), and dyspnea as measured by the Transitional Dyspnea Index (TDI). RESULTS: Fifteen subjects in the NPPV arm and 12 controls completed all the study visits. At 6 weeks and 3 months, the NPPV arm showed significant improvement in TDI total score. However, this effect persisted only in the TDI-Task at 6 months (P=0.03). NPPV use was associated with a small improvement in the CRQ-Mastery domain (0.6 versus -0.1, P=0.04). The arterial partial pressure of oxygen (PaO2) in the control arm worsened over the period of the study, whereas it remained stable in the NPPV arm (change -7.2 mmHg versus +2.1 mmHg, respectively, P=0.02). CONCLUSION: NPPV resulted in a small improvement in quality of life indices in stable COPD patients with PaCO2 <52 mmHg. Future larger studies will clarify the role of NPPV in this stable subgroup of patients with COPD.

Using Google Street View to audit the built environment: inter-rater reliability results.

BACKGROUND: Observational field audits are recommended for public health research to collect data on built environment characteristics. A reliable, standardized alternative to field audits that uses publicly available information could provide the ability to efficiently compare results across different study sites and time. PURPOSE: This study aimed to assess inter-rater reliability of built environment audits conducted using Google Street View imagery. METHODS: In 2011, street segments from St. Louis and Indianapolis were geographically stratified to ensure representation of neighborhoods with different land use and socioeconomic characteristics in both cities. Inter-rater reliability was assessed using observed agreement and the prevalence-adjusted bias-adjusted kappa statistic (PABAK). RESULTS: The mean PABAK for all items was 0.84. Ninety-five percent of the items had substantial (PABAK ≥ 0.60) or nearly perfect (PABAK ≥ 0.80) agreement. CONCLUSIONS: Using Google Street View imagery to audit the built environment is a reliable method for assessing characteristics of the built environment.

Assessing the built environment using omnidirectional imagery.

Observational audits commonly are used in public health research to collect data on built environment characteristics that affect health-related behaviors and outcomes, including physical activity and weight status. However, implementing in-person field audits can be expensive if observations are needed over large or geographically dispersed areas or at multiple points in time. A reliable and more efficient method for observational audits could facilitate extendibility (i.e., expanded geographic and temporal scope) and lead to more standardized assessment that strengthens the ability to compare results across different regions and studies. The purpose of the current study was to evaluate the degree of agreement between field audits and audits derived from interpretation of three types of omnidirectional imagery. Street segments from St. Louis MO and Indianapolis IN were stratified geographically to ensure representation of neighborhoods with different socioeconomic characteristics in both cities. Audits were conducted in 2008 and 2009 using four methods: field audits, and interpretation of archived imagery, new imagery, and Google Street View™ imagery. Agreement between field audits and image-based audits was assessed using observed agreement and the prevalence-adjusted bias-adjusted kappa statistic (PABAK). Data analysis was conducted in 2010. When measuring the agreement between field audits and audits from the different sources of imagery, the mean PABAK statistic for all items on the instrument was 0.78 (archived); 0.80 (new); and 0.81 (Street View imagery), indicating substantial to nearly perfect agreement among methods. It was determined that image-based audits represent a reliable method that can be used in place of field audits to measure several key characteristics of the built environment important to public health research.

Identifying risk factors for healthcare-associated infections from electronic medical record home address data.

BACKGROUND: Residential address is a common element in patient electronic medical records. Guidelines from the U.S. Centers for Disease Control and Prevention specify that residence in a nursing home, skilled nursing facility, or hospice within a year prior to a positive culture date is among the criteria for differentiating healthcare-acquired from community-acquired methicillin-resistant Staphylococcus aureus (MRSA) infections. Residential addresses may be useful for identifying patients residing in healthcare-associated settings, but methods for categorizing residence type based on electronic medical records have not been widely documented. The aim of this study was to develop a process to assist in differentiating healthcare-associated from community-associated MRSA infections by analyzing patient addresses to determine if residence reported at the time of positive culture was associated with a healthcare facility or other institutional location. RESULTS: We identified 1,232 of the patients (8.24% of the sample) with positive cultures as probable cases of healthcare-associated MRSA based on residential addresses contained in electronic medical records. Combining manual review with linking to institutional address databases improved geocoding rates from 11,870 records (79.37%) to 12,549 records (83.91%). Standardization of patient home address through geocoding increased the number of matches to institutional facilities from 545 (3.64%) to 1,379 (9.22%). CONCLUSIONS: Linking patient home address data from electronic medical records to institutional residential databases provides useful information for epidemiologic researchers, infection control practitioners, and clinicians. This information, coupled with other clinical and laboratory data, can be used to inform differentiation of healthcare-acquired from community-acquired infections. The process presented should be extensible with little or no added data costs.

The built environment and location-based physical activity.

BACKGROUND: Studies of the built environment and physical activity have implicitly assumed that a substantial amount of activity occurs near home, but in fact the location is unknown. PURPOSE: This study aims to examine associations between built environment variables within home and work buffers and moderate-to-vigorous physical activity (MVPA) occurring within these locations. METHODS: Adults (n=148) from Massachusetts wore an accelerometer and GPS unit for up to 4 days. Levels of MVPA were quantified within 50-m and 1-km home and work buffers. Multiple regression models were used to examine associations between five objective built environment variables within 1-km home and work buffers (intersection density, land use mix, population and housing unit density, vegetation index) and MVPA within those areas. RESULTS: The mean daily minutes of MVPA accumulated in all locations=61.1+/-32.8, whereas duration within the 1-km home buffers=14.0+/-16.4 minutes. Intersection density, land use mix, and population and housing unit density within 1-km home buffers were positively associated with MVPA in the buffer, whereas a vegetation index showed an inverse relationship (all p<0.05). None of these variables showed associations with total MVPA. Within 1 km of work, only population and housing unit density were significantly associated with MVPA within the buffer. CONCLUSIONS: Findings are consistent with studies showing that certain attributes of the built environment around homes are positively related to physical activity, but in this case only when the outcome was location-based. Simultaneous accelerometer-GPS monitoring shows promise as a method to improve understanding of how the built environment influences physical activity behaviors by allowing activity to be quantified in a range of physical contexts and thereby provide a more explicit link between physical activity outcomes and built environment exposures.

Socioeconomic indicators of heat-related health risk supplemented with remotely sensed data.

BACKGROUND: Extreme heat events are the number one cause of weather-related fatalities in the United States. The current system of alert for extreme heat events does not take into account intra-urban spatial variation in risk. The purpose of this study is to evaluate a potential method to improve spatial delineation of risk from extreme heat events in urban environments by integrating sociodemographic risk factors with estimates of land surface temperature derived from thermal remote sensing data. RESULTS: Comparison of logistic regression models indicates that supplementing known sociodemographic risk factors with remote sensing estimates of land surface temperature improves the delineation of intra-urban variations in risk from extreme heat events. CONCLUSION: Thermal remote sensing data can be utilized to improve understanding of intra-urban variations in risk from extreme heat. The refinement of current risk assessment systems could increase the likelihood of survival during extreme heat events and assist emergency personnel in the delivery of vital resources during such disasters.

The influence of regional basic science campuses on medical students' choice of specialty and practice location: a historical cohort study.

BACKGROUND: Indiana University School of Medicine (IUSM) employs eight regional basic science campuses, where half of the students complete their first two years of medical school. The other half complete all four years at the main campus in Indianapolis. The authors tested the hypothesis that training at regional campuses influences IUSM students to pursue primary care careers near the regional campuses they attended. METHODS: Medical school records for 2,487 graduates (classes of 1988-1997) were matched to the 2003 American Medical Association Physician Masterfile to identify the medical specialty and practice location of each graduate. Multivariate logistic regression was performed to assess the effect of regional campus attendance on students' choice of medical specialty and practice location, while simultaneously adjusting for several covariates thought to affect these career outcomes. RESULTS: Compared to Indianapolis students, those who attended a regional campus were somewhat more likely to be white, have parents with middle class occupations, and score slightly lower on the Medical College Admission Test. Any such differences were adjusted for in the regression models, which predicted that four of the regional campuses were significantly more likely than Indianapolis to produce family practitioners, and that five of the regional campuses were significantly more likely than the others to have former students practicing in the region. When analyzed collectively, attendance at any regional campus was a significant predictor of a primary care practice located outside the Indianapolis metropolitan area. CONCLUSION: Attending a regional campus for preclinical training appears to increase the likelihood of practicing primary care medicine in local communities.

Neighborhood greenness and 2-year changes in body mass index of children and youth.

BACKGROUND: Available studies of the built environment and the BMI of children and youth suggest a contemporaneous association with neighborhood greenness in neighborhoods with high population density. The current study tests whether greenness and residential density are independently associated with 2-year changes in the BMI of children and youth. METHODS: The sample included children and youth aged 3-16 years who lived at the same address for 24 consecutive months and received well-child care from a Marion County IN clinic network within the years 1996-2002 (n=3831). Multiple linear regression was used to examine associations among age- and gender-specific BMI z-scores in Year 2, residential density, and a satellite-derived measure of greenness, controlling for baseline BMI z-scores and other covariates. Logistic regression was used to model associations between an indicator of BMI z-score increase from baseline to Time 2 and the above-mentioned predictors. RESULTS: Higher greenness was significantly associated with lower BMI z-scores at Time 2 regardless of residential density characteristics. Higher residential density was not associated with Time 2 BMI z-scores in models regardless of greenness. Higher greenness was also associated with lower odds of children's and youth's increasing their BMI z-scores over 2 years (OR=0.87; 95% CI=0.79, 0.97). CONCLUSIONS: Greenness may present a target for environmental approaches to preventing child obesity. Children and youth living in greener neighborhoods had lower BMI z-scores at Time 2, presumably due to increased physical activity or time spent outdoors. Conceptualizations of walkability from adult studies, based solely on residential density, may not be relevant to children and youth in urban environments.

The beneficial effects of dichloroacetate in acute limb ischemia.

OBJECTIVE: The purpose of this study was to determine the effects of dichloroacetate (DCA) in acute limb ischemia. METHODS: Anterior tibialis muscle samples of DCA-treated and control animals (Sprague Dawley rats) were collected and assayed for pyruvate dehydrogenase activity, lactate, adenosine triphosphate, and creatine phosphate using spectrophotometry. A physiograph was used to measure fatigability. In an ischemia/reperfusion model using New Zealand rabbits, serum lactate and end-tidal CO2 were compared. Skeletal muscle was evaluated microscopically for muscle necrosis. RESULTS: DCA administration resulted in a 50% increase in pyruvate dehydrogenase activity (p = 0.025), reversal of the increase in lactate levels seen during acute limb ischemia (p = 0.41), a significant increase in the time to skeletal muscle fatigue (p = 0.05), a trend toward increased adenosine triphosphate (p = 0.07), and a significant increase in creatine phosphate (p < 0.02). DCA treatment resulted in a decrease in serum lactate (p < 0.01) and end-tidal CO2 (p < 0.001). CONCLUSION: In acute limb ischemia and reperfusion, DCA administration provides metabolic protection to skeletal muscle.

Green neighborhoods, food retail and childhood overweight: differences by population density.

PURPOSE: This study examines relationships between overweight in children and two environmentalfactors--amount of vegetation surrounding a child's place of residence and proximity of the child's residence to various types of food retail locations. We hypothesize that living in greener neighborhoods, farther from fast food restaurants, and closer to supermarkets would be associated with lower risk of overweight. DESIGN: Cross-sectional study. SETTING: Network of primary care pediatric clinics in Marion County, Indiana. SUBJECTS: We acquired data for 7334 subjects, ages 3 to 18 years, presenting for routine well-child care. MEASURES: Neighborhood vegetation and proximity to food retail were calculated using geographic information systems for each subject using circular and network buffers. Child weight status was defined using body mass index percentiles. Analysis. We used cumulative logit models to examine associations between an index of overweight, neighborhood vegetation, and food retail environment. RESULTS: After controlling for individual socio-demographics and neighborhood socioeconomic status, measures of vegetation and food retail significantly predicted overweight in children. Increased neighborhood vegetation was associated with decreased risk for overweight, but only for subjects residing in higher population density regions. Increased distance between a subject's residence and the nearest large brand name supermarkets was associated with increased risk of overweight, but only for subjects residing in lower population density regions. CONCLUSIONS: This research suggests that aspects of the built environment are determinants of child weight status, ostensibly by influencing physical activity and dietary behaviors.

Influence of hometown on family physicians' choice to practice in rural settings.

OBJECTIVE: This study examines the influence of a physician's hometown location on the choice of practice location, adjusting for confounding variables. METHODS: Medical school records for 2,487 Indiana University graduates (classes of 1988--1997) were matched to the American Medical Association's Masterfile data to identify the graduates' current practice locations and specialties. Urban influence codes were assigned to each county in Indiana for the purposes of defining metro or nonmetro locations. Physician practice locations were mapped using ArcGIS software. Chi-square tests, logistic regression, and analysis of variance were used to examine the influence of hometown on choice of practice location. RESULTS: Chi-square tests revealed significant associations between physician hometown and current practice location. Logistic regression, controlling for age and gender, predicted physicians (all specialties) from nonmetro hometowns were 4.7 times as likely to locate their practice in a nonmetro location as compared to their peers from metro hometowns. Similarly, family physicians from nonmetro hometowns were 4.4 times as likely to choose a nonmetro practice location. There was not a significant difference in the mean distance between hometown and practice location for physicians from nonmetro hometowns compared to those from metro hometowns. CONCLUSIONS: This study underscores the influence of physicians' hometown on their choice of practice location.

Improved outcomes in the recent management of secondary aortoenteric fistula.

OBJECTIVE: We reviewed the presentation, management, and late events in a recent experience with aortic graft-enteric communications (secondary aortoenteric fistula) to identify variables associated with poor outcomes. METHODS: Since 1991, 29 patients (19 men, 10 women; mean age, 70) presented with a secondary aortoenteric fistula. The duration from aortic graft implantation to aortoenteric fistula development ranged from 8 months to 180 months (mean, 47 months). Presenting symptoms included gastrointestinal bleeding (n = 25), sepsis and retroperitoneal abscess (n = 3), and ruptured para-anastomotic aneurysm (n = 1). One third (10/29) of patients were hypotensive at presentation. Repair was accomplished by graft excision with axillobifemoral bypass (17 simultaneous, 8 staged), graft excision with in situ deep vein replacement (n = 2), or graft excision with rifampin-treated prosthetic replacement (n = 2). Mean follow-up was 51 months, and the incidence of late events was reported by life table methods. RESULTS: The operative (< or = 30-day) mortality rate was 21%, with shock at presentation (P < .01), the need for preoperative transfusion (P < .01), and use of suprarenal aortic clamping during aortoenteric fistula repair (P = .03) associated with lethal outcome. Cumulative mortality related to aortoenteric fistula management was only 24% within an overall 5-year survival rate of 61%. Freedom from recurrent infection or amputation was 86% and 88% at 5 years, respectively, and assisted graft patency was 79%. Presence of staphylococcal species in 22% of patients and occasional operative findings of adjacent perigraft "biofilm" suggests that underlying indolent graft infection may contribute to the development of aortoenteric fistula in some cases. CONCLUSION: Outcomes associated with aortoenteric fistula repair were surprisingly favorable in the absence of preoperative hemodynamic instability.