There is a complex relationship between the environment and health. This document attempts to simplify this relationship by looking at a set of indicators. However, the results should be interpreted with caution.
For a start, the analyses are descriptive only, and it is not possible to determine causation from the results. Many factors combine together to affect the health of individuals and communities. Whether people are healthy or not is determined by their circumstances and environment. To a large extent, factors such as smoking, diet, exercise and housing all have considerable impacts on health; these factors were unable to be taken into consideration in this report.
Some indicators have been selected based on an association between the environment and health shown in epidemiological studies, although these associations may only hold for certain groups of the population (eg, the young and old). This has been noted where appropriate. When interpreting results at a regional level, the reader must be careful not to make the error known as the ‘ecological fallacy’, which involves inappropriately assigning the values of an aggregate group to an individual (Longley et al 2001).. For example, if the average income of people living in a region is $35,000, this does not mean that everyone in that region has an income of $35,000.
Finally, it is important to remember that although results for many of the indicators (particularly the state variables) have been presented at a regional level, actual exposure may differ among individuals. For many indicators, such as air quality, it is very difficult to measure the exact exposure and dose for individuals. When interpreting the state indicators it is also important to remember that health effects can be short term (acute) or long term (chronic), and may not be apparent for many years following the initial exposure. In addition, some individuals are more susceptible than others (the young, the old and the immune-compromised).