The importance of the environment for human health is well recognised. A recent WHO study estimated that modifiable environmental risk factors contribute to 24% of the global burden of disease (using disability-adjusted life years, or DALYs), and 23% of deaths globally (Pruss-Ustun and Corvalán 2006). This study also found significant regional differences, with higher environmental health burdens in developing countries. Nonetheless, results suggested that in developed countries in the Western Pacific (Australia, New Zealand, Japan, Singapore and Brunei), modifiable environmental risk factors still contribute up to 16% of the overall burden of disease and 18% of all deaths (Pruss-Ustun and Corvalán 2006).
Generally, environmental health issues can have a larger impact on the young. In particular, the WHO study found that, globally, for children aged 0–4 years, 36% of the burden of disease and 37% of mortality are attributable to modifiable environmental factors. Pruss-Ustun and Corvalán found that the main health issues with environmental risk factors that affect children in this age group are diarrhoea, malaria and respiratory infections.