What is your definition of a long, long time? Does it happen to coincide with the rise of agribusiness? With the subsidization of corn? Because that's about the timeframe when obesity began to rise, and then skyrocket in the US.
And average lifespan has increased 8 years over the past 50 years. EIGHT years. In an era of the greatest medical technology, medicines for everything, incredible inventions like the artificial heart, insane operations and scans to catch things before they happen, yet only 8 years in half a century? Yes, technology is helping keep sick people alive longer, that's for sure.
Agribusiness, crappy food, glucose out the ying yang, fast food and lack of exercise programs have a great deal to do with why people are needing that technology to help them live. Of course, there is always liposuction and staples. More technology.
You can take that up with the CDC, as the the validity of their source data, but they said it, not me:
http://www.cdc.gov/diabetes/faq/prediabetes.htm