The Harvard School of Public Health tracked thousands of female nurses during the 1990's. They found that those that consumed soft drinks on a regular basis were at a 83% increased risk of developing Type II Diabetes. The sugary fruit juices were even worse, it double the risk.
http://www.boston.com/news/globe/health_science/articles/2004/08/25/report_finds_soft_drinks_increase_risk_of_diabetes/
http://www.boston.com/news/globe/health_science/articles/2004/08/25/report_finds_soft_drinks_increase_risk_of_diabetes/