An estimated 23% of all premature deaths can be attributed to environmental factors that are modifiable and preventable, a report from the World Health Organization says.
“Many measures can indeed be taken almost immediately to reduce this environmental disease burden,” said Maria Neira, WHO’s director for public health and the environment.
“A few examples include the promotion of safe household water storage and better hygiene measures, the use of cleaner fuels, and safer, more judicious use and management of toxic substances in the home and workplace.”
The study analysed how different diseases—85 of the 102 major diseases—are affected by environmental risks and by how much.
The report concludes: “A better understanding of the disease impacts of various environmental factors can help guide policymakers in designing preventive health measures that not only reduce disease, but also reduce costs to the health-care system.” It says that overall, on a per person basis, the environmental burden was 15 times higher in developing countries than in developed countries and five times greater in children under 5 years of age than in the total population.
“Children bear the highest death toll, with more than four million environmentally caused deaths yearly, mostly in developing countries,” said Dr Neira. Diseases with the largest absolute burden included diarrhoea, lower respiratory infections, and malaria, says the report.
Together these disease are also the biggest killers and accounted for a quarter of all deaths in children aged under 5 years. In the case of diarrhoea, WHO estimates that about 94% of the burden is attributable to environmental and associated risk factors, such as unsafe drinking water and poor sanitation and hygiene, causing nearly 1.7 million deaths each year. Over half of the health burden of malnutrition was attributable to the same risk factors.
Halving the proportion of people without access to safe drinking water and sanitation by 2015, says WHO, would result in benefits that outweigh the costs by a ratio of 8:1, through savings in healthcare costs and gains in productivity.
Similarly, the study estimates that 42% of respiratory infections in developing countries and 20% of those in rich countries are due to environmental causes such as indoor and outdoor air pollution.
The report projects that targeted environmental interventions “could reduce the number of deaths from diarrhoea and lower respiratory infections by over 3 million each year.” In the case of malaria, WHO estimates that 42% of the global burden of the disease—or half a million deaths each year—could be prevented through sound environmental management.
Moreover, dengue and dengue haemorrhagic fever, it says, could be almost entirely prevented “by good management of water bodies in and around houses, which are breeding sites for the main mosquito vector.”
Environmental causes also accounted for 6% of adverse perinatal conditions in developed nations and for 11% in developing countries, WHO says, and for about 19% of all cancers, responsible for about 1.3 million deaths annually.
An estimated 800 000 children are estimated to be affected by exposure to lead, which could lead to mild mental retardation.
Phasing out leaded gasoline is one recommended, cost effective intervention. The study, which draws on contributions from more than 100 experts, says it’s likely that the analysis “underestimates the global burden.”
Many examples of risks and emerging risks, it says, “have not been adequately covered in the literature.”
Preventing Disease through Healthy Environments: Towards an Estimate of the Environmental Burden of Disease is available to order at www.who.int.