Environmental determinants of health
Many aspects of the natural environment can affect human health. In 2006, the World Health Organization (WHO) estimated the burden of disease from modifiable environmental factors and concluded that
Globally, an estimated 24% of the disease burden (healthy life years lost) and an estimated 23% of all deaths (premature mortality) was attributable to environmental factors.
The burden in developing countries was proportionally greater than in developed countries (25% vs 17%) and children were also more affected: among children aged 0–14 years, 36% of deaths were attributable to the environment (Figure 22a).
The conventional view of the natural environment, as described earlier, is the impact it has on human health, but people also have a major impact on the natural environment. By activities such as clearing forest, overfishing or the release of pollutants to the environment, humankind affects the quality of the water we drink and the air we breathe and risks the sustainable supply of healthy food. Given the choice, people prefer to live in a secure, predictable, attractive and diverse setting and may suffer ill health when such conditions deteriorate. Figure 22b sets out some of these consequences of human activity on the natural environment.
This chapter provides an overview of the interaction between the environment and human health. While thoughtful management and planning can minimise some of the more damaging impacts, events such as tsunamis or earthquakes are outside human control. The impact of such disasters is devastating and demands the rapid mobilisation of a range of agencies to address the immediate requirements of people who have lost homes, families and livelihoods and the longer-term needs of the physically injured and traumatised.