Effects of heat waves on mortality: effect modification and confounding by air pollutants.

BACKGROUND: Heat waves and air pollution are both associated with increased mortality. Their joint effects are less well understood. METHODS: We explored the role of air pollution in modifying the effects of heat waves on mortality, within the EuroHEAT project. Daily mortality, meteorologic, and air pollution data from nine European cities for the years 1990-2004 were assembled. We defined heat waves by taking both intensity and duration into account. The city-specific effects of heat wave episodes were estimated using generalized estimating equation models, adjusting for potential confounders with and without inclusion of air pollutants (particles, ozone, nitrogen dioxide, sulphur dioxide, carbon monoxide). To investigate effect modification, we introduced an interaction term between heat waves and each single pollutant in the models. Random effects meta-analysis was used to summarize the city-specific results. RESULTS: The increase in the number of daily deaths during heat wave episodes was 54% higher on high ozone days compared with low, among people age 75-84 years. The heat wave effect on high PM10 days was increased by 36% and 106% in the 75-84 year and 85+ year age groups, respectively. A similar pattern was observed for effects on cardiovascular mortality. Effect modification was less evident for respiratory mortality, although the heat wave effect itself was greater for this cause of death. The heat wave effect was smaller (15-30%) after adjustment for ozone or PM10. CONCLUSIONS: The heat wave effect on mortality was larger during high ozone or high PM10 days. When assessing the effect of heat waves on mortality, lack of adjustment for ozone and especially PM10 overestimates effect parameters. This bias has implications for public health policy.

Prevention and management of health hazards related to heatwaves.

OBJECTIVES: The general aim of the EuroHEAT project was to improve public health responses to weather extremes and, in particular, to heatwaves. STUDY DESIGN: The public health responses were developed on the basis of the overall results from the two-year project, "Improving Public Health Responses to Extreme Weather--EuroHEAT," co-funded by the European Commission (DG Sanco). METHODS: A literature review was carried out and a questionnaire was administered to health officials in charge of heat-health action plans in 2005 to survey existing heat-health action plans in Europe, and to identify models of the good practices for national/local preparedness planning. RESULTS: The adverse health effects of heatwaves are largely preventable. Prevention requires a range of actions at different levels: from health system preparedness coordinated with meteorological early warning systems to timely public and medical advice and improvements to housing and urban planning. These actions can be integrated in a defined heat-health action plan. Guidance for the development of heat-health action plans has been made available through EuroHEAT and is being used in various countries in the European Region. CONCLUSIONS: EuroHEAT recommends developing and implementing heat-health action plans at the national and regional levels in Europe to prevent, react upon and contain heat-related risks to health.

Prognostic factors in heat wave related deaths: a meta-analysis.

BACKGROUND: Although identifying individuals who are at increased risk of dying during heat waves and instituting protective measures represent an established strategy, the evidence supporting the components of this strategy and their strengths has yet to be evaluated. We conducted a meta-analysis of observational studies on risk and protective factors in heat wave-related deaths. METHODS: Using the OVID interface, we searched Medline (1966-2006) and CINHAL (1982-2006) databases. The Web sites of the World Health Organization, Institut National de Veille Sanitaire, and Centers for Disease Control and Prevention were also visited. The search terms included heat wave, heat stroke, heatstroke, sunstroke, and heat stress disorders. Eligible studies were case-control or cohort studies. Odds ratios (ORs) and information on study quality were abstracted by 2 investigators independently. Six case-control studies involving 1065 heat wave-related deaths were identified. RESULTS: Being confined to bed (OR, 6.44; 95% confidence interval [CI], 4.5-9.2), not leaving home daily (OR, 3.35; 95% CI, 1.6-6.9), and being unable to care for oneself (OR, 2.97; 95% CI, 1.8-4.8) were associated with the highest risk of death during heat waves. Preexisting psychiatric illness (OR, 3.61; 95% CI, 1.3-9.8) tripled the risk of death, followed by cardiovascular (OR, 2.48; 95% CI, 1.3-4.8) and pulmonary (OR, 1.61; 95% CI, 1.2-2.1) illness. Working home air-conditioning (OR, 0.23; 95% CI, 0.1-0.6), visiting cool environments (OR, 0.34; 95% CI, 0.2-0.5), and increasing social contact (OR, 0.40; 95% CI, 0.2-0.8) were strongly associated with better outcomes. Taking extra showers or baths (OR, 0.32; 95% CI, 0.1-1.1) and using fans (OR, 0.60; 95% CI, 0.4-1.1) were associated with a trend toward lower risk of death. CONCLUSION: The present study identified several prognostic factors that could help to detect those individuals who are at highest risk during heat waves and to provide a basis for potential risk-reducing interventions in the setting of heat waves.

Climate change and human health: estimating avoidable deaths and disease.

Human population health has always been central in the justification for sustainable development but nearly invisible in the United Nations Framework Convention on Climate Change negotiations. Current scientific evidence indicates that climate change will contribute to the global burden of disease through increases in diarrhoeal disease, vector-borne disease, and malnutrition, and the health impacts of extreme weather and climate events. A few studies have estimated future potential health impacts of climate change but often generate little policy-relevant information. Robust estimates of future health impacts rely on robust projections of future disease patterns. The application of a standardized and established methodology has been developed to quantify the impact of climate change in relation to different greenhouse gas emission scenarios. All health risk assessments are necessarily biased toward conservative best-estimates of health effects that are easily measured. Global, regional, and national risk assessments can take no account of irreversibility, or plausible low-probability events with potentially very high burdens on human health. There is no "safe limit" of climate change with respect to health impacts as health systems in some regions do not adequately cope with the current climate variability. Current scientific methods cannot identify global threshold health effects in order for policymakers to regulate a "tolerable" amount of climate change. We argue for the need for more research to reduce the potential impacts of climate change on human health, including the development of improved methods for quantitative risk assessment. The large uncertainty about the future effects of climate change on human population health should be a reason to reduce greenhouse gas emissions, and not a reason for inaction.

Планы действий по защите здоровья населения от воздействия аномальной жары: руководство

В результате климатических изменений меняются погодные условия и по-видимому возрастает частота экстремальных погодных явлений, включая волны жары. В Европейском регионе ВОЗ ряд таких волн, имевших место в последнее время, стал причиной дополнительных случаев смерти, несмотря на то, что неблагоприятное влияние жаркой погоды и волн жары на здоровье людей в основном может быть предотвращено. Для эффективной профилактики заболеваемости и смертности, связанных с жарой, необходим комплекс действий на различных уровнях, включая создание и поддержание метеорологических систем раннего предупреждения, своевременное распространение рекомендаций о мерах профилактики и защиты, совершенствование жилищного и городского строительства, а также принятие мер, обеспечивающих готовность системы здравоохранения и системы социальной защиты к принятию необходимых мер. Все эти действия могут быть интегрированы в специальном плане защиты населения в периоды жары. Данное руководство является результатом работы в рамках проекта EuroHEAT, посвященного улучшению действий общественного здравоохранения во время экстремальных погодных явлений/волн жары, который финансируется совместно ВОЗ и Европейской комиссией. В руководстве объясняется важность создания планов защиты населения в периоды жары, указываются их основные характеристики и элементы, а также приводятся примеры из нескольких европейских стран, приступивших к реализации и оценке таких планов.

Heat–health action plans: guidance

Climate change is leading to variations in weather patterns and an apparent increase in extreme weather events, including heat-waves. Recent heat-waves in the WHO European Region have led to a rise in related mortality, but the adverse health effects of hot weather and heat-waves are largely preventable. Prevention requires a portfolio of actions at different levels, including meteorological early warning systems, timely public and medical advice, improvements to housing and urban planning, and ensuring that health care and social systems are ready to act. These actions can be integrated into a defined heat–health action plan. This guidance results from the EuroHEAT project on improving public health responses to extreme weather/heat-waves, co-funded by WHO and the European Commission. It explains the importance of the development of heat–health action plans, their characteristics and core elements, with examples from several European countries that have begun their implementation and evaluation.