A simple answer to the cause of disease consists of inheritance and environmental risk factors, but these are very complex issues to deal with. The human environment involves exposure to many different physical, biological and chemical agents. This exposure can be divided into different categories. General environmental exposure such as air pollution is something we are all exposed to and, as individuals, do not have the possibility to change. Certain environmental exposures are easy to avoid if one possesses the knowledge.
Toxic mushrooms are one example.
Chemicals that have a low acute toxicity and occur as contaminants in food products are extremely difficult for the individual to avoid. Persistent halogenated aromatic hydrocarbons such as chlorinated dioxins are an example. Often, qualified research is needed in order to become aware of the problem. In addition to this there are socially accepted toxins - individuals do not choose to avoid the exposure even with good knowledge of the potential consequences. It is also common to either under or overestimate a certain risk due to gender, age or cultural, educational and other factors.