World Bank Special:
Double burden

Ian Johnson and Kseniya Lvovsky show how the health of the poor suffers most from both traditional and modern environmental hazards

It has long been recognized that the environment in which people live – from the household to the community to the global level – significantly affects their health. Every year in developing countries an estimated 3 million people die prematurely from water-related diseases and 2 million people die from exposure to stove smoke inside their homes. The largest proportion of these deaths are among infants and young children, followed by women, from poor rural families who lack access to safe water, sanitation and modern household fuels. Over 1 million people die annually from vector-borne malaria, with the vast majority of deaths in poverty-stricken Africa. Another million people die from air pollution in the urban environment, and there is a reason to believe that here too the poor suffer most.

Health impacts
Many environmental policies and regulations are motivated by public health concerns. Until recently, however, the magnitude of health impacts from exposure to various environmental risks and the relative contribution of these risks were not known. Recent estimates by Murray and Lopez in The Global Burden of Disease (Harvard University Press, 1996) suggest that premature death and illness as a result of major environmental health risks account for a fifth of the disease burden in the developing world. This is comparable to malnutrition and larger than all other preventable risk factors and groups of disease causes. By contrast, such environmental health risks contribute less than 5 per cent of the disease burden in rich countries, despite much higher levels of urbanization, industrial development and energy consumption, which are usually associated with environmental pollution and health problems.

The populations of rich countries also enjoy better general health; the total burden of illness and death from all causes per million people is about half that of developing countries. However, the disease burden from environmental risks is smaller by a factor of ten.

This underscores the basic, although often overlooked, fact that while growth in industry, power generation, transport and other attributes of economic development brings new environmental challenges, the largest environmental threats to human health come from the poor living conditions that result from the lack of development and growth. Environmental health risks, therefore, can be grouped into two broad categories:

  • Traditional hazards, related to poverty and lack of development, such as lack of safe water, scant sanitation and waste disposal, indoor air pollution, and a wide spread of disease vectors (e.g. malaria).

  • Modern hazards, caused by development that lacks environmental safeguards, such as urban (outdoor) air pollution and exposure to agro-industrial chemicals and waste, including occupational exposure.

Traditional environmental hazards affect developing countries and the poor most. Their impact exceeds that of modern health hazards by a ratio of 10 for Africa, 5 for Asian countries (except for China), and 2.5 for the Middle East (see Figure 2). Water-borne diseases, caused by inadequate water supply and sanitation, impose an especially large health burden in the African, Asian and Pacific regions. In India alone, more than 700,000 children under five years old die annually from diarrhoea. More than half of the world’s households use unprocessed solid fuels, particularly biomass (crop residues, wood and dung) for cooking and heating in inefficient stoves without proper ventilation, exposing people – mainly poor women and children – to high levels of indoor air pollution (see Box). About half of all these deaths – nearly 1 million – occur in India and China. Vector-borne diseases are affected by a range of environmental conditions and factors, including polluted and standing water; open sewers and certain types of sanitation; clogged storm drains; and floods. In Africa alone, malaria is responsible for about 800,000 deaths annually. A study of environmental health in the Indian state of Andhra Pradesh found that the burden of disease from traditional risks falls disproportionately on the poorest 40 per cent of all households. At the same time, environmental health outcomes show significant variations that cannot be simply explained by a household’s economic status, and hence reflect indicators of human development other than income measure alone.

Conversely, modern threats to human health prevail in industrialized countries that have managed drastically to reduce the exposure of their citizens to traditional environmental hazards. More worrying, however, is the fact that the contribution of modern environmental risks to the disease burden in most developing countries is similar to that in rich ones; in quite a few countries it is even greater (see Figure 2). Urban air pollution, for example, hits its highest levels in China, India and in a number of cities in Asia and Latin America.

The urban poor bear the brunt of air pollution because they often live in densely populated neighbourhoods that use dirty household fuels, burn garbage nearby, and are close to traffic corridors or industries. They travel in open vehicles or walk, and spend much more time outdoors. Thus, the world’s poor are increasingly experiencing the ‘double burden’ of both traditional and modern environmental health risks.

Multiple links
Thus environmental health is yet another dimension of the multi-faceted nature of poverty. The links between poor environmental health and other dimensions of poverty are complex and multiple, reinforcing each other in various ways. Poor people typically face greater environmental health risks in their surroundings because they live in unhealthy locations – such as low-lying and marginal lands – and lack basic infrastructure services, like clean water and sanitation. They are more vulnerable because they are less able – as a result of insufficient education and information, daily drudgery and hardship – to adjust their behaviour to moderate their exposure. Additionally, they are the most susceptible to the effects of such exposures because of the simultaneous effect of several factors, such as exposure to indoor smoke and water-borne pathogens, exacerbated by malnutrition and inadequate health care.
Environmental health is yet another dimension of the multi-faceted nature of poverty
Rapid urbanization and the uncontrolled growth of slums are changing the landscape of environmental health concerns and posing significant new challenges in Africa, Asia and Latin America. They increase the ‘double burden’ for the urban and semi-urban poor, adding risks from modern transport and industrial pollution to exposures from dirty cooking fuels, primitive stoves, crowding, and poor access to water and sanitation. Malaria is also becoming an urban issue in some parts of the world, partly as a result of infrastructure failures such as inadequate drainage systems. Climate change is likely to worsen this situation, while globalization and the liberalization of trade may exacerbate the transmission of some diseases.

The environmental challenges of development and globalization require concerted action but the much higher environmental health costs of living in poverty and lacking basic infrastructure and other services must not be neglected. The best policies will address both types of health damage in a synergistic manner. Such policies include those that promote strong growth and the structures for good governance and can both safeguard the environment and respond to the needs of the poor. Trade-offs are sometimes inevitable. However, they should be made with a full understanding of the net health impacts that result.

Mitigating risks
Better infrastructure and energy services for households and communities are key measures in mitigating the most daunting environmental risks to health. So are interventions to improve housing and to control vectors, including effective health-care systems and equitable education policies. For example, measures like improved water and sanitation, household energy, housing, vector control and pollution management could prevent up to 29 per cent of the total burden of disease in sub-Saharan Africa. Health sector interventions that target the disease clusters associated with these environmental risks could reduce it by a further 28 per cent. Providing water supplies to rural households has been found to be among the most cost-effective preventive health interventions in India. Reducing modern risks calls for measures to prevent and abate pollution. These, in turn, require setting and enforcing environmental standards, developing a culture of environmental compliance and creating effective incentives.

The resources of governments in developing countries are severely constrained and are beset by a multitude of pressing social needs. To meet these needs it is vital to mobilize private sector investments and initiatives to finance infrastructure and improve the delivery of services in both urban and rural areas, within a sound regulatory framework that includes environmental safeguards.

Holistic approach
The environment-health nexus emphasizes that improvements in people’s health require a holistic, multi-sectoral approach to mitigating major risks by integrating cost-effective efforts in infrastructure and human development areas, and by building effective institutions at all levels of governance, including in the communities themselves. A holistic approach is particularly important for improving the health of the poor, who are most vulnerable both to the main environmental hazards and to deficiencies in health service delivery. The World Bank Environment Strategy – developed in extensive consultation with various stakeholders in client countries, other donors and international non-governmental organizations – considers environmental health a top priority and calls for a greater focus on this principal development outcome in Bank operations across all relevant sectors

Ian Johnson is Vice President of the World Bank, and Kseniya Lvovsky is Lead Environmental Economist in the World Bank’s South Asia Region.


Lack of modern household energy threatens the health of poor women and children

Biomass is the energy source of the poor. When traditional biomass fuels – mainly wood, straw and dung – burn in simple cooking stoves during the preparation of meals, the air inside homes becomes heavily polluted with toxic smoke. Exposure to this biomass smoke increases the risk of acute respiratory infection (ARI) in children under five years of age.

Children in the Gambia found riding on their mothers’backs as they cooked over smoky stoves were six times more likely to develop ARI then unexposed children. In Nepal, the incidence of moderate and severe cases among two-year-olds increased as they spent greater numbers of hours near the fire. A study in the United Republic of Tanzania found that children younger than five years who died of ARI were almost three times more likely to be sleeping in a room with an open stove than healthy children in the same age group. Studies in South America and India have shown that exposure to indoor air pollution severely reduces lung function in children.

Exposure to high indoor smoke levels is associated with pregnancy-related problems such as stillbirth and low birth weight. Studies in Colombia, India, Mexico, Nepal and Papua New Guinea show that non-smoking women who have cooked on biomass stoves for many years exhibit a higher prevalence of chronic lung disease (asthma and chronic bronchitis) than those who have not. Some 18 per cent of blindness in India is attributed to the use of biomass fuels.

The detrimental health effects of traditional biomass energy go beyond exposure to harmful smoke. In Nepal, rural women are so busy with their daily chores, including spending a disproportionate amount of time collecting fuel, that they are forced to give local beer to their children to keep them quiet. Nepalese women suffer a high incidence of uterine prolapse, probably due to carrying heavy wood loads soon after delivery. In rural areas of India, women are engaged for six hours a day in collecting fuelwood and fodder and in cooking. In some areas, this extreme physical drudgery causes women serious reproductive problems and mental disorders.

Source: Indoor Air Pollution: Energy and Health for the Poor, World Bank/ESMAP Newsletter, Issue No. 1, September 2000; Issue No. 3, February 2001

This issue:
Contents | Editorial K. Toepfer | Answering poor health | Tackling water poverty | Everything connects | Up the gross natural product | Stopping AIDS | Whose city is it anyway? | Nutrition | At a glance: Poverty | Competition | World Bank Special: ‘Double burden’ | It’s not just, pollution | Smoke and fires | Breaking the cycle of poison | Pharmacies for life | Viewpoint: Change – or decay | The environment: why we must not give up | World Atlas of Coral Reefs | GTOS: An eyeglass on our planet

Complementary articles in other issues:
Didier J. Cherpital: Breaking the cycle (Disasters) 2001
Alcira Kreimer and Margaret Arnold: The poor suffer most (Disasters) 2001
Kristalina Georgieva: Disproportionate effects (Beyond 2000) 2000
David Wheeler, David Shaman, Susmita Dasgupta, Benoit Laplante and Hua Wang:
New millennium, new regulation (Beyond 2000) 2000
Mark Malloch Brown: Empowering the poor (The environment millennium) 2000
Leslie Roberts: Focus: Environmental degradation (Oceans) 1998

AAAS Atlas of Population and Environment:
Forest products,
Air pollution