Background: Wildfire events are increasing in prevalence in the western United States. Research has found mixed results on the degree to which exposure to wildfire smoke is associated with an increased risk of mortality. Methods: We tested for an association between exposure to wildfire smoke and non-traumatic mortality in Washington State, USA. We characterized wildfire smoke days as binary for grid cells based on daily average PM 2.5 concentrations, from June 1 through September 30, 2006-2017. Wildfire smoke days were defined as all days with assigned monitor concentration above a PM 2.5 value of 20.4 μg/m 3 , with an additional set of criteria applied to days between 9 and 20.4 μg/m 3. We employed a case-crossover study design using conditional logistic regression and time-stratified referent sampling, controlling for humidex. Results: The odds of all-ages non-traumatic mortality with same-day exposure was 1.0% (95% CI: − 1.0-4.0%) greater on wildfire smoke days compared to non-wildfire smoke days, and the previous day's exposure was associated with a 2.0% (95% CI: 0.0-5.0%) increase. When stratified by cause of mortality, odds of same-day respiratory mortality increased by 9.0% (95% CI: 0.0-18.0%), while the odds of same-day COPD mortality increased by 14.0% (95% CI: 2.0-26.0%). In subgroup analyses, we observed a 35.0% (95% CI: 9.0-67.0%) increase in the odds of same-day respiratory mortality for adults ages 45-64. Conclusions: This study suggests increased odds of mortality in the first few days following wildfire smoke exposure. It is the first to examine this relationship in Washington State and will help inform local and state risk communication efforts and decision-making during future wildfire smoke events.

BackgroundExposure to excessive heat kills more people than any other weather-related phenomenon, aggravates chronic diseases, and causes direct heat illness. Strong associations between extreme heat and health have been identified through increased mortality and hospitalizations and there is growing evidence demonstrating increased emergency department visits and demand for emergency medical services (EMS). The purpose of this study is to build on an existing regional assessment of mortality and hospitalizations by analyzing EMS demand associated with extreme heat, using calls as a health metric, in King County, Washington (WA), for a 6-year period.MethodsRelative-risk and time series analyses were used to characterize the association between heat and EMS calls for May 1 through September 30 of each year for 2007–2012. Two EMS categories, basic life support (BLS) and advanced life support (ALS), were analyzed for the effects of heat on health outcomes and transportation volume, stratified by age. Extreme heat was model-derived as the 95th (29.7 °C) and 99th (36.7 °C) percentile of average county-wide maximum daily humidex for BLS and ALS calls respectively.ResultsRelative-risk analyses revealed an 8 % (95 % CI: 6–9 %) increase in BLS calls, and a 14 % (95 % CI: 9–20 %) increase in ALS calls, on a heat day (29.7 and 36.7 °C humidex, respectively) versus a non-heat day for all ages, all causes. Time series analyses found a 6.6 % increase in BLS calls, and a 3.8 % increase in ALS calls, per unit-humidex increase above the optimum threshold, 40.7 and 39.7 °C humidex respectively. Increases in “no” and “any” transportation were found in both relative risk and time series analyses. Analysis by age category identified significant results for all age groups, with the 15–44 and 45–64 year old age groups showing some of the highest and most frequent increases across health conditions. Multiple specific health conditions were associated with increased risk of an EMS call including abdominal/genito-urinary, alcohol/drug, anaphylaxis/allergy, cardiovascular, metabolic/endocrine, diabetes, neurological, heat illness and dehydration, and psychological conditions.ConclusionsExtreme heat increases the risk of EMS calls in King County, WA, with effects demonstrated in relatively younger populations and more health conditions than those identified in previous analyses.

A growing body of literature suggests that restrictive public health measures implemented to control COVID-19 have had negative impacts on physical activity. We examined how Stay Home orders in Houston, New York City, and Seattle impacted outdoor physical activity patterns, measured by daily bicycle and pedestrian count data. We assessed changes in activity levels between the period before and during Stay Home orders. Across all three cities, we found significant changes in bicycle and pedestrian counts from the period before to the period during Stay Home orders. The direction of change varied by location, likely due to differing local contexts and outbreak progression. These results can inform policy around the use of outdoor public infrastructure as the COVID-19 pandemic continues.

AbstractIncreased morbidity and mortality have been associated with extreme heat events, particularly in temperate climates. Few epidemiologic studies have considered the impact of extreme heat events on hospitalization rates in the Pacific Northwest region. This study quantifies the historic (May to September 1990–2010) heat-morbidity relationship in the most populous Pacific Northwest County, King County, Washington. A relative risk (RR) analysis was used to explore the association between heat and all non-traumatic hospitalizations on 99th percentile heat days, whereas a time series analysis using a piecewise linear model approximation was used to estimate the effect of heat intensity on hospitalizations, adjusted for temporal trends and day of the week. A non-statistically significant 2% [95% CI: 1.02 (0.98, 1.05)] increase in hospitalization risk, on a heat day vs. a non-heat day, was noted for all-ages and all non-traumatic causes. When considering the effect of heat intensity on admissions, we found a statistically significant 1.59% (95% CI: 0.9%, 2.29%) increase in admissions per degree increase in humidex above 37.4°C. Admissions stratified by cause and age produced statistically significant results with both relative risk and time series analyses for nephritis and nephrotic syndromes, acute renal failure, and natural heat exposure hospitalizations. This study demonstrates that heat, expressed as humidex, is associated with increased hospital admissions. When stratified by age and cause of admission, the non-elderly age groups (<85 years) experience significant risk for nephritis and nephrotic syndromes, acute renal failure, natural heat exposure, chronic obstructive pulmonary disease, and asthma hospitalizations.

Extreme heat has been associated with increased mortality, particularly in temperate climates. Few epidemiologic studies have considered the Pacific Northwest region in their analyses. This study quantified the historical (May to September, 1980–2010) heat-mortality relationship in the most populous Pacific Northwest County, King County, Washington. A relative risk (RR) analysis was used to explore the relationship between heat and all-cause mortality on 99th percentile heat days, while a time series analysis, using a piece-wise linear model fit, was used to estimate the effect of heat intensity on mortality, adjusted for temporal trends. For all ages, all causes, we found a 10 % (1.10 (95 % confidence interval (CI), 1.06, 1.14)) increase in the risk of death on a heat day versus non-heat day. When considering the intensity effect of heat on all-cause mortality, we found a 1.69 % (95 % CI, 0.69, 2.70) increase in the risk of death per unit of humidex above 36.0 °C. Mortality stratified by cause and age produced statistically significant results using both types of analyses for: all-cause, non-traumatic, circulatory, cardiovascular, cerebrovascular, and diabetes causes of death. All-cause mortality was statistically significantly modified by the type of synoptic weather type. These results demonstrate that heat, expressed as humidex, is associated with increased mortality on heat days, and that risk increases with heat’s intensity. While age was the only individual-level characteristic found to modify mortality risks, statistically significant increases in diabetes-related mortality for the 45–64 age group suggests that underlying health status may contribute to these risks.

To aid health adaptation decision-making, there are increasing efforts to provide climate projections at finer temporal and spatial scales. Relying solely on projected climate changes for longer-term decisions makes the implicit assumption that sources of vulnerability other than climate change will remain the same, which is not very probable. Over longer time horizons, this approach likely over estimates the extent to which climate change could alter the magnitude and pattern of health outcomes, introducing systematic bias into health management decisions. To balance this potential bias, decision-makers also need projections of other drivers of health outcomes that are, like climate change, recognized determinants of some disease burdens. Incorporating projections via an iterative process that allows for regular updates based on new knowledge and experience has the potential to improve the utility of fine-scale climate projections in health system adaptation to climate change.

Context: Wildfire events are increasing in prevalence and intensity in the Pacific Northwest. Effective communication of health risks and actions to reduce exposure to wildfire smoke is imperative. Objective: We assessed the content of wildfire smoke risk messages from government organizations and mainstream media during a major wildfire smoke event in August 2018. Design: We conducted a content analysis of wildfire smoke risk information communicated by local and state government organizations and the mainstream media. Setting: Eight Washington State counties during a statewide wildfire smoke event in August 2018. Main Outcome Measure: Leveraging the Extended Parallel Process Model and information in the existing literature on wildfire smoke and health, we assessed messages for the presence of information regarding health risk, personal interventions, administrative interventions, vulnerable populations, and trusted sources of information. Summary statistics were calculated to identify common messages about recommended interventions, vulnerable populations cited, and trusted sources of public health information. Results: Of the 273 identified government and media messages on wildfire smoke, the majority (71% and 66%) contained information about health risks. However, only 46% and 33% of government and media messages contained information about personal interventions to reduce risk, and 37% and 14% of government and media messages contained information about administrative interventions to reduce risk. Less than half of government and media messages (28% and 31%) contained information specific to vulnerable populations, and 58% and 46% of government and media messages contained any reference to a trusted source of information. Conclusions: While information about wildfire smoke and health risks was communicated during Washington's August 2018 wildfire smoke event, there remains considerable opportunity to include additional information about interventions, vulnerable populations, and trusted sources of information. We recommend several opportunities to improve and evaluate risk communication and risk reduction before, during, and after future wildfire smoke events.

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