Mortality and burden of disease from unhealthy environments: In 2016, 13.7 million people died as a result of living or working in an unhealthy environment, representing 24% of all deaths. When accounting for both death and disability, the fraction of the global burden of disease due to the environment is 23%. In children under five years, up to 28% of all deaths could be prevented, if environmental risks were removed. 68% of these attributable deaths and 51% of attributable DALYs could be estimated with evidence-based comparative risk assessment methods, the impacts of other environmental exposures were assessed through expert opinion.

The WHO report on the burden of disease from environmental risks analysed the 133 diseases listed in the WHO’s Global Health Observatory and found 101 linked to the environment

# An estimated 12.6 million deaths each year are attributable to unhealthy environments
# 24% of all estimated global deaths are linked to the environment ...That’s roughly 13.7 million deaths a year
# Children under five and adults between 50 and 75 years old are most affected by the environment.
# Low- and middle-income countries bear the greatest share of environmental disease.
# In 2016, household air pollution was responsible for 3.8 million deaths, and 7.7% of the global mortality

This second edition of Preventing Disease through Healthy Environments:

• Updates the 2006 publication and presents the latest evidence on environment-disease links and their devastating impact on global health.
• Systematically analyses and quantifies how different diseases are impacted by environmental risks, detailing the regions and populations most vulnerable to environmentally mediated death, disease and injury.
• Is exhaustive in its coverage – the health impacts of environmental risks across more than100 diseases and injuries are covered. Some of these environmental factors are well known, such as unsafe drinking-water and sanitation, and air pollution and indoor stoves; others less so, such as climate change or the built environment.
• Highlights promising areas for immediate intervention and gaps where further research is needed to establish the linkages and quantify the burden of disease for various environmental risk factors.

The report’s findings result from a systematic process: literature reviews for all the disease categories addressed; compilation of available risk factor-disease estimates; and surveys of more than 100 experts worldwide. The best available scientific evidence together with approximations and expert evaluations for knowledge gaps are combined to provide up-to-date estimates. The data and methods underlying the health statistics for the previous and current editions have, however, undergone major modifications, and thus the trend analysis is restricted to selected parameters.

Findings confirm that 23% of global deaths and 26% of deaths among children under five are due to modifiable environmental factors. Heading this list are stroke, ischaemic heart disease, diarrhoea and cancers. This environmentally mediated disease burden is much higher in lower income countries with the exception of certain noncommunicable diseases, such as cardiovascular diseases and cancers, where the per capita disease burden is greater in the developed world. ( see infographic)