Quantifying environmental health impacts

Preventing disease through healthy environments: towards an estimate of the environmental burden of disease - Radio interviews

Dr Maria Neira, Director, Public Health and the Environment Department
Dr Annette Prüss-Üstün, Scientist, Public Health and the Environment Department
Dr Carlos Corvalan, Scientist, Public Health and the Environment Department

1. WHO's Public Health and Environment - What is being done

Dr Maria Neira, Director, Public Health and Environment, World Health Organization

Q. - What is WHO doing in the field of Health and Environment?

First we are making clear for everybody the linkages between health and the environment are definitely very very strong. That's the first message for all of us. 25% of the burden of disease is linked to t he environment and we are convinced that if we attack those hazards and we clean up from the environmental those risks we will have a very positive impact on our health.

Q. - What are the advantages of a healthier environment (win-win strategy)

Clearly the benefits will be for both fields - environment and public health. If we do interventions at the environmental level, that will allow us to have a better and cleaner air, clean water, and safe water, we will be protected for pesticides or for toxic that will prevent cancer in other diseases - definitely we will have an impact on health and at the same time, the public health people need to realize the importance of working as well at the environmental level.

Q. - Why is environment the public health issue of the future?

For the 21st century, we need not only to address the classic issues related to our health like diarrhoeal diseases linked to the lack of clean water, and lack of access to sanitation, but we need to make sure that what is discussed in this century about energy, about urbanization, about air pollution will have an impact on our health and therefore we need to be present in that agenda. The health issues are very critical on the environmental agenda.

Q. - What is the key take home message of this report?

Healthy environments are the key for your better health, so if you are looking to protect your health make sure your leaders, your policy makers and yourself you protect the environment and you make interventions at the environmental level will give you benefits now - but will as well protect the future of your children.


Dr Annette Pruss-Ustun, Scientist, Public Health and the Environment Department, World Health Organization

How does the environment influence our health?

About one quarter of global disease is caused by environmental factors that we could in fact change. The environment influences our health through the air we breathe, the water we drink, radiation and noise, the work environment, the built environment, and also the climate and ecosystem -- a large wide variety of influences.

Q. - What are the diseases caused by environmental factors?

Polluted air causes respiratory diseases, unclean water and lacking sanitation causes diarrhoea, poorly managed water bodies cause vector diseases such as malaria, poorly designed streets, cities and buildings cause injuries -- and these are just a few examples. Altogether more than 80% of all major diseases and injuries are impacted by factors in our environment. More than 3.5 million deaths each year are from respiratory infections, diarrhoeal diseases and malaria alone.

Talking about non-communicable diseases - cancers may caused by polluted air, chemicals or radiation, cardiovascular diseases are related to stress at the workplace, and chemicals. These two diseases alone trigger almost another 4 million deaths a year.

Suicides and violence are impacted by our environment -- violent behaviour for example can be triggered by chemicals we're exposed to, such as lead.

Q. - What are the most striking findings of this global survey ?

I would say that the main finding That the environment affects practically all parts of our body or system, and that health can be greatly improved by a healthier environment. All of the environmental factors we included in our study are modifiable and could prevent disease -- rather than waiting for diseases to happen and treating afterwards.

Q. - Can you explain to me what are the modifiable environmental factors?

These are all the part of the environment that are amenable to change, for example by technical solutions we know, or by policy and regulations that have been implemented.

Q. - Which countries or regions are most affected?

All countries and regions are affected but not in the same way. According to our study the greatest impact is in the developing countries, and in particular children in those countries. This is because the traditional risks to health are very important in these countries such as unsafe water, inadequate sanitation or using solid fuels for cooking. However, we believe that this study underestimates the full impacts that environmental factors can have, in particular the more subtle links that are more difficult to study and estimate, for example chemicals that reach us through food, water or air.

This is why for developed countries we think that our current estimate does still not reflect the full impact of our environment that has on our health.

Q. - What is your key message?

The strong link is that the environment has on our health, and is this large yet unused opportunity that our health can really be improved by making our environment safer.

3. The health issues

Q. - What are the main health challenges and responses to a changing environment?

We have several challenges but I can mention two important ones: The increasing scale of the problems and their increasing complexity.

Consider the scale of the problem: We have gone through a process of very localized contamination, think of indoor air pollution in homes , a very ancient problem; through community or neighbourhood problems such as the release of human and domestic wastes; through city wide problems, such as urban air pollution; then regional and inter-country problems such as trans-boundary pollution of rivers, lakes, or atmosphere; Now we have the ability to affect the whole world, so we are talking about global problems such as climate change and ecosystem disruption.

On the increasing complexity issue, we have also moved from human exposures which we can easily observe and quantify, such as drinking contaminated water and getting diarrhoea, and this may happen just a few hours later… or respiratory disease from burning biomass fuels indoors, which may take a bit longer to occur - the health effects - I mean - and also then to very complex exposure pathways, as those related to climate change.

Take for example the complexity of changed climate, impacting on agriculture and leading to local level malnutrition. The source of the problem can be very far away, and there may be a long time lag before the health impacts are observed…..and whether the health outcome occurs or not depends on many other variables.

The response is also complex: In some population groups we observe all these environmental problems are occurring simultaneously. These are often the poor in poor countries. The response involves coordinated work by several sectors, not just health. And it requires a new focus, where we understand the need to prevent disease by improving our environment. For me the keyword is prevention.

Q. - How can environmental interventions prevent disease?

We have to understand environmental interventions do prevent disease. This is why governments try to reduce air pollution, and take measures to provide people with clean water. But the answers are not always simple and they do require an investment. However if you consider the costs and benefits of different interventions, one quickly realizes that investment pays, often several times the initial cost of the intervention.

The settings approach - healthy cities, healthy villages approach - uses this logic. The idea is to agree on key, priority interventions to makes our surroundings a better, healthier, place. Improving Health or reducing illness is the main goal.

Most communities also thinks in terms of enhancing their overall well-being. Health, after all, has long ago been defined as a state of complete physical, mental and social well-being.

Q. - How big is the population at risk, and how can people benefit from a better environment?

What we need to understand when we speak of environmental risk factors in general, the population at risk is the whole world. Almost everyone, at any given time is exposed to some environmental risk factor. For some it may be very serious, like for the mother who burns wood in unventilated indoor space to cook a meal. Or the child that drinks polluted water. For others it may be the elevated air pollution levels in a city, which are hard to escape. Yet for others it may be their workplace, or the food they eat, the concentration of heat in a city, like heat waves, or elevated levels of UV radiation, like when you go to the beach on holidays.

When we live in a home setting free of pollution, with a good source of clean water and safe sanitation, in a healthy city that promotes healthy transport, such as bicycle paths, and yes, also environmental stimulus for a good diet (which is not always the case in settings that offer nothing but unhealthy foods), then we can clearly say that the environment, including the social environment, is promoting better health, and that people are benefiting from a better environment.

Q. - What are the main diseases affecting children?

Children do a lot worse than adults when it comes to unhealthy environments.

While around a quarter of deaths could be prevented from healthy environments in the overall population, in children we could prevent over one third of deaths through environmental interventions. This means that our children would benefit the most from interventions for healthy environments. These include diarrhoeal diseases from contaminated water or poor sanitation and hygiene; or respiratory diseases from indoor and outdoor air pollution; or vector-borne diseases like malaria; or malnutrition; injuries, and many others….

But there are also important health gaps: child mortality rates - which are related to the environment - in the worst regions of the world is 180 times higher than in best regions. If we could only eliminate child mortality from environmentally related diarrhoeal and respiratory diseases, we would be saving the lives of 2 million children under 5 every year.

Last update:

11 December 2010 02:16 CET