A lot of psychological research aims to give support to something we may have already thought was true intuitively. This article falls into that category. Feeling that your life has purpose, meaning or is important in some way is associated with a longer life. I'm sure most of us can think of examples of people from our lives who because they kept active, were generous in some way to others, they lived a more vibrant and possibly longer life.
http://www.healthday.com/Article.asp?AID=627835
http://www.healthday.com/Article.asp?AID=627835