It is a truism to say that the environment affect a person's overall health. Let me give you a few examples.
First, the most obvious example would be in places that have been affected by some sort of natural disaster. For example, the tsunami in Japan created radioactive problems as it damaged a nuclear reactor in Fukushima. There will be serious health issues for a long time.
Second, the air quality is also an important factor. Even yesterday on bloomberg.com there was an article on Hong Kong and their poor air quality and how the poor air quality leads to various sicknesses like heart and lung diseases.
Third, due to pollution in the seas, there are also problems with seafood. For example, a lot of fish now have very high levels of mercury, which is very harmful for people.