Over 10 times more people die in circulatory diseases than accidents ([source][1]). Nevertheless people fear (in general) more accidents than circulatory disease. In addition, there are statistically even more unlikely things that people fear, eg. lightning.

What is the reason for this?

One thing that came to my mind is that these unlikely things are more reported on news, but there must be also somethings else behind this.

  [1]: http://www.theguardian.com/news/datablog/2012/nov/06/deaths-mortality-rates-cause-death-2011