R. Sari Kovats

International study of temperature, heat and urban mortality: the ‘ISOTHURM’ project

BACKGROUND This study describes heat- and cold-related mortality in 12 urban populations in low- and middle-income countries, thereby extending knowledge of how diverse populations, in non-OECD countries, respond to temperature extremes. METHODS The cities were: Delhi, Monterrey, Mexico City, Chiang Mai, Bangkok, Salvador, São Paulo, Santiago, Cape Town, Ljubljana, Bucharest and Sofia. For each city, daily mortality was examined in relation to ambient temperature using autoregressive Poisson models (2- to 5-year series) adjusted for season, relative humidity, air pollution, day of week and public holidays. RESULTS Most cities showed a U-shaped temperature-mortality relationship, with clear evidence of increasing death rates at colder temperatures in all cities except Ljubljana, Salvador and Delhi and with increasing heat in all cities except Chiang Mai and Cape Town. Estimates of the temperature threshold below which cold-related mortality began to increase ranged from 15 degrees C to 29 degrees C; the threshold for heat-related deaths ranged from 16 degrees C to 31 degrees C. Heat thresholds were generally higher in cities with warmer climates, while cold thresholds were unrelated to climate. CONCLUSIONS Urban populations, in diverse geographic settings, experience increases in mortality due to both high and low temperatures. The effects of heat and cold vary depending on climate and non-climate factors such as the population disease profile and age structure. Although such populations will undergo some adaptation to increasing temperatures, many are likely to have substantial vulnerability to climate change. Additional research is needed to elucidate vulnerability within populations.

El Niño and health

El Niño Southern Oscillation (ENSO) is a climate event that originates in the Pacific Ocean but has wide-ranging consequences for weather around the world, and is especially associated with droughts and floods. The irregular occurrence of El Niño and La Niña events has implications for public health. On a global scale, the human effect of natural disasters increases during El Niño. The effect of ENSO on cholera risk in Bangladesh, and malaria epidemics in parts of South Asia and South America has been well established. The strongest evidence for an association between ENSO and disease is provided by time-series analysis with data series that include more than one event. Evidence for ENSOs effect on other mosquito-borne and rodent-borne diseases is weaker than that for malaria and cholera. Health planners are used to dealing with spatial risk concepts but have little experience with temporal risk management. ENSO and seasonal climate forecasts might offer the opportunity to target scarce resources for epidemic control and disaster preparedness.

Vulnerability to winter mortality in elderly people in Britain: population based study

Abstract Objective To examine the determinants of vulnerability to winter mortality in elderly British people. Design Population based cohort study (119 389 person years of follow up). Setting 106 general practices from the Medical Research Council trial of assessment and management of older people in Britain. Participants People aged ≥ 75 years. Main outcome measures Mortality (10 123 deaths) determined by follow up through the Office for National Statistics. Results Month to month variation accounted for 17% of annual all cause mortality, but only 7.8% after adjustment for temperature. The overall winter:non-winter rate ratio was 1.31 (95% confidence interval 1.26 to 1.36). There was little evidence that this ratio varied by geographical region, age, or any of the personal, socioeconomic, or clinical factors examined, with two exceptions: after adjustment for all major covariates the winter:non-winter ratio in women compared with men was 1.11 (1.00 to 1.23), and those with a self reported history of respiratory illness had a winter:non-winter ratio of 1.20 (1.08 to 1.34) times that of people without a history of respiratory illness. There was no evidence that socioeconomic deprivation or self reported financial worries were predictive of winter death. Conclusion Except for female sex and pre-existing respiratory illness, there was little evidence for vulnerability to winter death associated with factors thought to lead to vulnerability. The lack of socioeconomic gradient suggests that policies aimed at relief of fuel poverty may need to be supplemented by additional measures to tackle the burden of excess winter deaths in elderly people.

An Approach for Assessing Human Health Vulnerability and Public Health Interventions to Adapt to Climate Change

Assessments of the potential human health impacts of climate change are needed to inform the development of adaptation strategies, policies, and measures to lessen projected adverse impacts. We developed methods for country-level assessments to help policy makers make evidence-based decisions to increase resilience to current and future climates, and to provide information for national communications to the United Nations Framework Convention on Climate Change. The steps in an assessment should include the following: a) determine the scope of the assessment; b) describe the current distribution and burden of climate-sensitive health determinants and outcomes; c) identify and describe current strategies, policies, and measures designed to reduce the burden of climate-sensitive health determinants and outcomes; d) review the health implications of the potential impacts of climate variability and change in other sectors; e) estimate the future potential health impacts using scenarios of future changes in climate, socioeconomic, and other factors; f) synthesize the results; and g) identify additional adaptation policies and measures to reduce potential negative health impacts. Key issues for ensuring that an assessment is informative, timely, and useful include stakeholder involvement, an adequate management structure, and a communication strategy.

Impacts of Climate Change on Indirect Human Exposure to Pathogens and Chemicals from Agriculture

Objective Climate change is likely to affect the nature of pathogens and chemicals in the environment and their fate and transport. Future risks of pathogens and chemicals could therefore be very different from those of today. In this review, we assess the implications of climate change for changes in human exposures to pathogens and chemicals in agricultural systems in the United Kingdom and discuss the subsequent effects on health impacts. Data sources In this review, we used expert input and considered literature on climate change; health effects resulting from exposure to pathogens and chemicals arising from agriculture; inputs of chemicals and pathogens to agricultural systems; and human exposure pathways for pathogens and chemicals in agricultural systems. Data synthesis We established the current evidence base for health effects of chemicals and pathogens in the agricultural environment; determined the potential implications of climate change on chemical and pathogen inputs in agricultural systems; and explored the effects of climate change on environmental transport and fate of different contaminant types. We combined these data to assess the implications of climate change in terms of indirect human exposure to pathogens and chemicals in agricultural systems. We then developed recommendations on future research and policy changes to manage any adverse increases in risks. Conclusions Overall, climate change is likely to increase human exposures to agricultural contaminants. The magnitude of the increases will be highly dependent on the contaminant type. Risks from many pathogens and particulate and particle-associated contaminants could increase significantly. These increases in exposure can, however, be managed for the most part through targeted research and policy changes.

The Direct Impact of Climate Change on Regional Labor Productivity

ABSTRACT Global climate change will increase outdoor and indoor heat loads, and may impair health and productivity for millions of working people. This study applies physiological evidence about effects of heat, climate guidelines for safe work environments, climate modeling, and global distributions of working populations to estimate the impact of 2 climate scenarios on future labor productivity. In most regions, climate change will decrease labor productivity, under the simple assumption of no specific adaptation. By the 2080s, the greatest absolute losses of population-based labor work capacity (in the range 11% to 27%) are seen under the A2 scenario in Southeast Asia, Andean and Central America, and the Caribbean. Increased occupational heat exposure due to climate change may significantly impact on labor productivity and costs unless preventive measures are implemented. Workers may need to work longer hours, or more workers may be required, to achieve the same output and there will be economic costs of lost production and/or occupational health interventions against heat exposures.

An ecological time-series study of heat-related mortality in three European cities

BackgroundEurope has experienced warmer summers in the past two decades and there is a need to describe the determinants of heat-related mortality to better inform public health activities during hot weather. We investigated the effect of high temperatures on daily mortality in three cities in Europe (Budapest, London, and Milan), using a standard approach.MethodsAn ecological time-series study of daily mortality was conducted in three cities using Poisson generalized linear models allowing for over-dispersion. Secular trends in mortality and seasonal confounding factors were controlled for using cubic smoothing splines of time. Heat exposure was modelled using average values of the temperature measure on the same day as death (lag 0) and the day before (lag 1). The heat effect was quantified assuming a linear increase in risk above a cut-point for each city. Socio-economic status indicators and census data were linked with mortality data for stratified analyses.ResultsThe risk of heat-related death increased with age, and females had a greater risk than males in age groups ≥65 years in London and Milan. The relative risks of mortality (per °C) above the heat cut-point by gender and age were: (i) Male 1.10 (95%CI: 1.07–1.12) and Female 1.07 (1.05–1.10) for 75–84 years, (ii) M 1.10 (1.06–1.14) and F 1.08 (1.06–1.11) for ≥85 years in Budapest (≥24°C); (i) M 1.03 (1.01–1.04) and F 1.07 (1.05–1.09), (ii) M 1.05 (1.03–1.07) and F 1.08 (1.07–1.10) in London (≥20°C); and (i) M 1.08 (1.03–1.14) and F 1.20 (1.15–1.26), (ii) M 1.18 (1.11–1.26) and F 1.19 (1.15–1.24) in Milan (≥26°C). Mortality from external causes increases at higher temperatures as well as that from respiratory and cardiovascular disease. There was no clear evidence of effect modification by socio-economic status in either Budapest or London, but there was a seemingly higher risk for affluent non-elderly adults in Milan.ConclusionWe found broadly consistent determinants (age, gender, and cause of death) of heat related mortality in three European cities using a standard approach. Our results are consistent with previous evidence for individual determinants, and also confirm the lack of a strong socio-economic gradient in heat health effects currently in Europe.

Hotspots in climate change and human health

The health effects of climate change will affect vulnerable low income populations first, and this review provides convincing evidence of the public health importance of monitoring hotspots of climate change and health Is climate change a serious threat to health? According to the most recent international assessments it unquestionably is, although its impact depends on where you live, your age, access to health care, and your public health infrastructure.1–4 Arguably, climate change is one of the largest environmental and health equity challenges of our times; wealthy energy consuming nations are most responsible for the emissions that cause global warming, yet poor countries are most at risk. In a globalised world, however, the health of populations in rich countries is affected as a result of international travel, trade, and human migration. Mapping “hotspots” of ecological risk has proved to be a useful construct for prioritising and focusing resources to stem the threat of losing biodiversity. Similarly, identifying hotspots in climate change and human health may help public health practitioners in anticipating and preventing any additional burden of disease. #### Summary box Health effects from climate change will stem from altered temperatures, extremes of precipitation (floods and droughts), air pollution, and infectious diseases Although risk may be low compared with current acute health crises, the attributable burden of such a widespread global phenomenon may be quite high Any region or population with concurrent environmental or socioeconomic stresses will be at risk Long term disease surveillance must be maintained or established in suspected hotspots of climate change and health risks to enhance detection and prevention of disease Climate change represents one of the greatest environmental and health equity challenges of our times; wealthy energy consuming nations are most responsible for global warming, yet poor countries are at most risk Clinicians should recognise these …

Ozone, heat and mortality: acute effects in 15 British conurbations

Background Acute associations between mortality and ozone are largely accepted, though recent evidence is less conclusive. Evidence on ozone–heat interaction is sparse. We assess effects of ozone, heat, and their interaction, on mortality in Britain. Methods Acute effects of summer ozone on mortality were estimated using data from 15 conurbations in England and Wales (May–September, 1993–2003). 2-day means of daily maximum 8-h ozone were entered into case series analyses, controlling for particulate matter with aerodynamic diameter of <10 μm, natural cubic splines of temperature, and other factors. Heat effects were estimated, comparing adjusted mortality rates at 97.5th and 75th percentiles of 2-day mean temperature. A separate model employed interaction terms to assess whether ozone effects increased on ‘hot days’ (where 2-day mean temperature exceeded the whole-year 95th percentile). Other heat metrics, and non-linear ozone effects, were also examined. Results Adverse ozone and heat effects occurred in nearly all conurbations. The mean mortality rate ratio for heat effect across conurbations was 1.071 (1.050–1.093). The mean ozone rate ratio was 1.003 per 10 μg/m3 ozone increase (95% CI 1.001 to 1.005). On ‘hot days’ the mean ozone effect reached 1.006 (1.002–1.009) per 10 μg/m3, though ozone–heat interaction was significant in London only. On substituting maximum for mean temperature, the overall ozone effect reduced to null, though evidence remained of effects on hot days, particularly in London. An estimated ozone effect threshold was below current guidelines in ‘mean temperature’ models. Conclusion While heat showed robust effects on summer mortality, estimates for ozone depended upon the modelling of temperature. However, there was some evidence that ozone effects were worse on hot days, whichever temperature measure was used.

Cryptosporidiosis Decline after Regulation, England and Wales, 1989-2005

Since new drinking water regulations were implemented in England and Wales in 2000, cryptosporidiosis has been significantly reduced in the first half of the year but not in the second. We estimate an annual reduction in disease of 905 reported cases and ≈6,700 total cases.