OBJECTIVES: Geographic Information Systems (GIS) is a powerful tool for assessing exposure in epidemiologic studies. We used GIS to determine the geographic extent of contamination by perfluorooctanoic acid, C8 (PFOA) that was released into the environment from the DuPont Washington Works Facility located in Parkersburg, West Virginia. METHODS: Paper maps of pipe distribution networks were provided by six local public water districts participating in the community cross-sectional survey, the C8 Health Project. Residential histories were also collected in the survey and geocoded. We integrated the pipe networks and geocoded addresses to determine which addresses were serviced by one of the participating water districts. The GIS-based water district assignment was then compared to the participants' self-reported source of public drinking water. RESULTS: There were a total of 151,871 addresses provided by the 48,800 participants of the C8 Health Project that consented to geocoding. We were able to successfully geocode 139,067 (91.6%) addresses, and of these, 118,209 (85.0%) self-reported water sources were confirmed using the GIS-based method of water district assignment. Furthermore, the GIS-based method corrected 20,858 (15.0%) self-reported public drinking water sources. Over half (54%) the participants in the lowest GIS-based exposure group self-reported being in a higher exposed water district. CONCLUSIONS: Not only were we able to correct erroneous self-reported water sources, we were also able to assign water districts to participants with unknown sources. Without the GIS-based method, the reliance on only self-reported data would have resulted in exposure misclassification.
Cross-Sectional Studies ; Drinking Water* ; Drinking* ; Epidemiologic Studies ; Geographic Information Systems* ; Geographic Mapping ; Methods ; Washington ; Water ; West Virginia

PURPOSE: Shorter response time is very important for critically-ill patients. The study utilized a linear planning and simulation technique to design a two-tiered system with advanced life support (ALS) ambulances. METHODS: We collected the ambulance run-sheet data from a fire department from January, 2006 to December, 2007 to determine emergency medical service (EMS) demands. The location of patient ambulance stations were mapped by geocoding and the most appropriate number and location of ambulances was calculated with the linear planning method. The planning result was validated with a discrete simulation. RESULTS: The initial enrollment was 227,377 cases of 119 calls. After geocoding, 170,472 (74.9%) cases were directly matched, 56,899 (25.0%) were indirectly matched, and (0.1%) were not matched. The latter were excluded. Using the linear planning method, the number of additional ambulances was calculated for a new two-tiered ambulance system that could achieve a 90% service level. From the current single-tiered system with 112 ambulances to a two-tiered system of 211 basic life support (BLS) units and 40 ALS units, the BLS service level for minor patients could be raised to 90%. For severely-ill patients , a BLS and ALS service level of up to 82% and 89%, respectively, service level could be achieved. The new two-tiered system was validated with the discrete simulation. After the simulation, the BLS and ALS service level for severely-ill patients reached 85% and 93%, respectively. As well, a 100% BLS service level for minor patients was achieved. CONCLUSION: Linear planning and discrete simulation with GIS data enabled the simulation of a two-tiered ambulance system that can shorten the response time of the current single-tiered system.
Advanced Cardiac Life Support ; Ambulances ; Emergencies ; Emergency Medical Services ; Fires ; Geographic Mapping ; Humans ; Reaction Time

OBJECTIVE: In respect of the health and safety of the public, universal access to health care is an issue of the greatest importance. The geographic distribution of doctors is one of the important factors contributing to access to health care. The aim of this study is to assess the imbalances in the geographic distribution of neurosurgeons across Korea.METHODS: Population data was obtained from the National Statistical Office. We classified geographic groups into 7 metropolitan cities, 78 non-metropolitan cities, and 77 rural areas. The number of doctors and neurosurgeons per 100000 populations in each county unit was calculated using the total number of doctors and neurosurgeons at the country level from 2009 to 2015. The density levels of neurosurgeon and doctor were calculated and depicted in maps.RESULTS: Between 2009 and 2015, the number of neurosurgeons increased from 2002 to 2557, and the ratio of neurosurgeons per 100000 populations increased from 4.02 to 4.96. The number of neurosurgeons per 100000 populations was highest in metropolitan cities and lowest in rural areas from 2009 to 2015. A comparison of the geographic distribution of neurosurgeons in 2009 and 2015 showed an increase in the regional gap. The neurosurgeon density was affected by country unit characteristics (p=0.000).CONCLUSION: Distribution of neurosurgeons throughout Korea is uneven. Neurosurgeons are being increasingly concentrated in a limited number of metropolitan cities. This phenomenon will need to be accounted when planning for a supply of neurosurgeons, allocation of resources and manpower, and the provision of regional neurosurgical services.
Geographic Mapping ; Health Manpower ; Health Services Accessibility ; Hospital Distribution Systems ; Korea ; Neurosurgeons ; Neurosurgery ; Resource Allocation