Here are some articles I found to be very imformative and just for fun want to share them. Also, I would recommend a book The Spirit Level Why Greater Equality Makes Societies Stronger by Richard Wilkinson and Kate Pickett two epidemiologists who reveal 30 years of data in regards to public health and economic inequality.
This article includes 4 other article links all worth reading in regards to altruism.
These two are in regards to the environment.
This is in regards to Chiropractics...