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Using Forecast and Observed Weather Data to Assess Performance of Forecast Products in Identifying Heat Waves and Estimating Heat Wave Effects on Mortality

October 6, 2014 Comments off

Using Forecast and Observed Weather Data to Assess Performance of Forecast Products in Identifying Heat Waves and Estimating Heat Wave Effects on Mortality
Source: Environmental Health Perspectives (CDC)

Background:
Heat wave and health warning systems are activated based on forecasts of health-threatening hot weather.

Objective:
We estimated heat–mortality associations based on forecast and observed weather data in Detroit, Michigan, and compared the accuracy of forecast products for predicting heat waves.

Methods:
We derived and compared apparent temperature (AT) and heat wave days (with heat waves defined as ≥ 2 days of daily mean AT ≥ 95th percentile of warm-season average) from weather observations and six different forecast products. We used Poisson regression with and without adjustment for ozone and/or PM10 (particulate matter with aerodynamic diameter ≤ 10 μm) to estimate and compare associations of daily all-cause mortality with observed and predicted AT and heat wave days.

Results:
The 1-day-ahead forecast of a local operational product, Revised Digital Forecast, had about half the number of false positives compared with all other forecasts. On average, controlling for heat waves, days with observed AT = 25.3°C were associated with 3.5% higher mortality (95% CI: –1.6, 8.8%) than days with AT = 8.5°C. Observed heat wave days were associated with 6.2% higher mortality (95% CI: –0.4, 13.2%) than non–heat wave days. The accuracy of predictions varied, but associations between mortality and forecast heat generally tended to overestimate heat effects, whereas associations with forecast heat waves tended to underestimate heat wave effects, relative to associations based on observed weather metrics.

Conclusions:
Our findings suggest that incorporating knowledge of local conditions may improve the accuracy of predictions used to activate heat wave and health warning systems.

Proximity to Natural Gas Wells and Reported Health Status: Results of a Household Survey in Washington County, Pennsylvania

October 3, 2014 Comments off

Proximity to Natural Gas Wells and Reported Health Status: Results of a Household Survey in Washington County, Pennsylvania
Source: Environmental Health Perspectives (CDC)

Background:
Little is known about the environmental and public health impact of unconventional natural gas extraction activities including hydraulic fracturing that occur near residential areas.

Objectives:
To assess the relationship between household proximity to natural gas wells and reported health symptoms.

Methods: We conducted a hypothesis generating health symptom survey of 492 persons in 180 randomly selected households with ground-fed wells in an area of active natural gas drilling. Gas well proximity for each household was compared to the prevalence and frequency of reported dermal, respiratory, gastrointestinal, cardiovascular, and neurological symptoms.

Results:
The number of reported health symptoms per person was higher among residents living 2 km from the nearest gas well (mean 1.60 ± 2.14, p=0.02). In a model that adjusted for age, gender, household education, smoking, awareness of environmental risk, work type, and animals in house, reported skin conditions were more common in households 2 km from the nearest gas well (OR= 4.1; 95% CI: 1.4, 12.3; p=0.01). Upper respiratory symptoms were also more frequently reported in persons living in households less than 1 km from gas wells (39%) compared to households 1-2 km or >2 km from the nearest well (31 and 18%, respectively) (p=0.004). No equivalent correlation was found between well proximity and other reported groups of respiratory, neurological, cardiovascular, or gastrointestinal conditions.

Conclusion:
While these results should be viewed as hypothesis generating, and the population studied was limited to households with a ground fed water supply, proximity of natural gas wells may be associated with the prevalence of health symptoms including dermal and respiratory conditions in residents living near natural gas extraction activities. Further study of these associations, including the role of specific air and water exposures, is warranted.

The Societal Costs and Benefits of Commuter Bicycling: Simulating the Effects of Specific Policies Using System Dynamics Modeling

July 14, 2014 Comments off

The Societal Costs and Benefits of Commuter Bicycling: Simulating the Effects of Specific Policies Using System Dynamics Modeling
Source: Environmental Health Perspectives

Background:
Shifting to active modes of transport in the trip to work can achieve substantial co-benefits for health, social equity, and climate change mitigation. Previous integrated modeling of transport scenarios has assumed active transport mode share and has been unable to incorporate acknowledged system feedbacks.

Objectives:
We compared the effects of policies to increase bicycle commuting in a car-dominated city and explored the role of participatory modeling to support transport planning in the face of complexity.

Methods:
We used system dynamics modeling (SDM) to compare realistic policies, incorporating feedback effects, nonlinear relationships, and time delays between variables. We developed a system dynamics model of commuter bicycling through interviews and workshops with policy, community, and academic stakeholders. We incorporated best available evidence to simulate five policy scenarios over the next 40 years in Auckland, New Zealand. Injury, physical activity, fuel costs, air pollution, and carbon emissions outcomes were simulated.

Results:
Using the simulation model, we demonstrated the kinds of policies that would likely be needed to change a historical pattern of decline in cycling into a pattern of growth that would meet policy goals. Our model projections suggest that transforming urban roads over the next 40 years, using best practice physical separation on main roads and bicycle-friendly speed reduction on local streets, would yield benefits 10–25 times greater than costs.

Conclusions:
To our knowledge, this is the first integrated simulation model of future specific bicycling policies. Our projections provide practical evidence that may be used by health and transport policy makers to optimize the benefits of transport bicycling while minimizing negative consequences in a cost-effective manner. The modeling process enhanced understanding by a range of stakeholders of cycling as a complex system. Participatory SDM can be a helpful method for integrating health and environmental outcomes in transport and urban planning.

Outdoor Particulate Matter Exposure and Lung Cancer: A Systematic Review and Meta-Analysis

July 14, 2014 Comments off

Outdoor Particulate Matter Exposure and Lung Cancer: A Systematic Review and Meta-Analysis
Source: Environmental Health Perspectives

Background:
Particulate matter (PM) in outdoor air pollution was recently designated a Group I carcinogen by the International Agency for Research on Cancer (IARC). This determination was based on the evidence regarding the relationship of PM2.5 and PM10 to lung cancer risk; however, the IARC evaluation did not include a quantitative summary of the evidence.

Objective:
To provide a systematic review and quantitative summary of the evidence regarding the relationship between PM and lung cancer.

Methods:
We conducted meta-analyses of studies examining the relationship of exposure to PM2.5 and PM10 with lung cancer incidence and mortality. In total, 18 studies met inclusion criteria and provided the information necessary to estimate the change in lung cancer risk per 10-μg/m3 increase in exposure to PM. We used random effects analyses to allow between study variability to contribute to meta-estimates.

Results:
The meta-relative risk (95% CI) for lung cancer associated with PM2.5 was 1.09 (95% CI: 1.04, 1.14). The meta-relative risk of lung cancer associated with PM10 was similar, but less precise: 1.08 (95% CI: 1.00, 1.17). Estimates were robust to restriction to studies that considered potential confounders, as well as sub-analyses by exposure assessment method. Analyses by smoking status showed that lung cancer risk associated with PM2.5 was greatest for former smokers, 1.44 (95% CI: 1.04, 1.22) followed by never smokers, 1.18 (95% CI: 1.00, 1.39), and then current smokers, 1.06 (95% CI: 0.97, 1.15). In addition, meta-estimates for adenocarcinoma associated with PM2.5 and PM10 were 1.40 (95% CI: 1.07, 1.83) and 1.29 (95% CI: 1.02, 1.63), respectively.

Conclusion:
The results of these analyses, and the decision of the IARC working group to classify PM and outdoor air pollution as carcinogenic (Group 1), further justify efforts to reduce exposures to air pollutants that can arise from many sources.

Summertime Acute Heat Illness in U.S. Emergency Departments from 2006 through 2010: Analysis of a Nationally Representative Sample

July 10, 2014 Comments off

Summertime Acute Heat Illness in U.S. Emergency Departments from 2006 through 2010: Analysis of a Nationally Representative Sample
Source: Environmental Health Perspectives

Background:
Patients with acute heat illness present primarily to emergency departments (EDs), yet little is known regarding these visits.

Objective:
To describe acute heat illness visits to US EDs from 2006-2010 and identify factors associated with hospital admission or death-in-the-ED.

Methods:
We extracted ED case-level data from the Nationwide Emergency Department Sample (NEDS) for 2006-10, defining cases as ED visits from May-September with any heat illness diagnosis (ICD-9-CM 992.0-992.9). We correlated visit rates and temperature anomalies analyzed demographics and ED disposition, identified risk factors for adverse outcomes, and examined ED case fatality rates (CFR).

Results:
There were 326,497 (95% CI: 308,372-344,658) cases, with 287,875 (88.2%) treated-and-released, 38,392 (11.8%) admitted, and 230 (0.07%) died-in-the-ED. Heat illness diagnoses were first-listed in 68%. 74.7% had heat exhaustion, 5.4% heat stroke. Visit rates were highly correlated with annual temperature anomalies (correlation coefficient 0.90, p=0.037). Treat-and-release rates were highest for younger adults (26.2/100,000/year), while hospitalization and death-in-the-ED rates were highest for older adults (6.7 and 0.03/100,000/year respectively); all rates were highest in rural areas. Heat stroke had an ED CFR of 99.4/10,000 (78.7-120.1) visits and was diagnosed in 77.0% of deaths. Adjusted odds of hospital admission or death-in-the-ED were higher among elders, males, urban and low income residents, and those with chronic conditions.

Conclusions:
Heat illness presented to the ED frequently, with highest rates in rural areas. Case definitions should include all diagnoses. Visit rates were correlated with temperature anomalies. Heat stroke had a high ED CFR. Males, elders, and the chronically ill were at greatest risk of admission or death-in-the-ED. Chronic disease burden exponentially increased this risk.

Daily Mean Temperature and Clinical Kidney Stone Presentation in Five U.S. Metropolitan Areas: A Time-Series Analysis

July 10, 2014 Comments off

Daily Mean Temperature and Clinical Kidney Stone Presentation in Five U.S. Metropolitan Areas: A Time-Series Analysis
Source: Environmental Health Perspectives

Background:
High ambient temperatures are a risk factor for nephrolithiasis, but the precise relationship between temperature and kidney stone presentation is unknown.

Objectives:
Our objective was to estimate associations between mean daily temperature and kidney stone presentation according to lag time and temperatures.

Methods:
Using a time series design and distributed lag non-linear models, we estimated the relative risk (RR) of kidney stone presentation associated with mean daily temperatures, including cumulative RR for a 20-day period, and RR for individual daily lags through 20 days. Our analysis used MarketScan data for 60,433 patients who presented for evaluation or treatment of kidney stones from 2005–2011 in Atlanta, Chicago, Dallas, Los Angeles, and Philadelphia.

Results:
Associations between mean daily temperature and kidney stone presentation were not monotonic, and there was variation in the exposure-response curve shapes and the strength of associations at different temperatures. However, in most cases RRs increased for temperatures above the reference value of 10°C. The cumulative RR for a daily mean temperature of 30°C versus 10°C was 1.38 in Atlanta (95% CI: 1.07, 1.79), 1.37 in Chicago (95% CI: 1.07, 1.76), 1.36 in Dallas (95% CI: 1.10, 1.69), 1.11 in Los Angeles (95% CI: 0.73, 1.68), and 1.47 in Philadelphia (95% CI: 1.00, 2.17). Kidney stone presentations also were positively associated with temperatures < 2°C in Atlanta, and < 10°C in Chicago and Philadelphia. In 4 cities, the strongest association between kidney stone presentation and a daily mean temperature of 30 versus 10°C was estimated for lags ≤ 3 days.

Conclusions:
In general, kidney stone presentations increased with higher daily mean temperatures, with the strongest associations estimated for lags of only a few days. These findings further support an adverse effect of high temperatures on nephrolithiasis.

Take Care in the Kitchen: Avoiding Cooking-Related Pollutants

June 25, 2014 Comments off

Take Care in the Kitchen: Avoiding Cooking-Related Pollutants
Source: Environmental Health Perspectives

Carbon monoxide (CO), nitrogen dioxide (NO2), and particulate matter (PM) are harmful air pollutants that pose significant short- and long-term health risks. Emitted from coal-fired power plants, vehicle exhaust pipes, and other combustion sources, they’re among six primary pollutants monitored by the U.S. Environmental Protection Agency (EPA) through the Clean Air Act. These same pollutants are also some of the most common contributors to unhealthy air inside U.S. homes, due in part to a ubiquitous and possibly surprising activity: cooking.

Researchers now understand that the process of cooking food and even simply operating stoves—particularly gas appliances—can emit a cocktail of potentially hazardous chemicals and compounds. Within our homes, these pollutants are less diluted than they are outdoors, and in the absence of proper ventilation, they often are trapped inside. The World Health Organization has established general guidelines for indoor air quality and is currently developing specific limits related to burning solid fuels for cooking and heating. However, indoor air in nonindustrial buildings is not regulated by the EPA or any other U.S. agency.

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