It is old but I just found it:
http://www.drclas.harvard.edu/publications/revistaonline/spring-2012/caribbean-baseball
Here are some more:
http://www.e-steroid.com/steroids-blog/dominican-baseball-players-more-prone-to-steroids-use.html
http://sports.espn.go.com/mlb/news/story?id=2033711
Have a nice day!!