The same applies to other lesions or diseases. The stronger the predisposition is and the greater the number of risk-factors which a person is exposed to, the higher the risk of developing a certain disease is. In the case of cancer, inheritance is probably the predominant factor in only a few per cent of all cases. Likewise, in only a small fraction of cancer cases is one specific environmental risk factor enough to generate the disease. In most cases, a combination of a number of inherited predispositions and complex exposure to a large variety of environmental risk factors is involved.
Human behavior is very complex.
On the basis of on education, cultural behavior, age, sex and many other factors we all interpret a certain risk very differently. Other factors, such as the time between exposure and health effect, have a major influence on whether we consider something to be dangerous or not. If, for instance, all the people who die in smoking- related diseases were to die when they smoked their first cigarette, cigarettes would be considered extremely dangerous and would be banned in all societies. No one would be allowed to even touch a cigarette without very strict safety measurements. But since there is a time delay of decades from the start of smoking and the occurrence of lung cancer it is very hard to see the connection.