Diabetes 10X less frequent among people getting lots of vitamin D
Note:
This data has not yet been adjusted for cofactor
It is possible that people getting the vitamin D test were taking better care of their health than people in NHANES
Grassroots Health has for several years been providing low cost vitamin D tests and keeping track of the health of the test users.

Their data as of May 2011

Grassroots Health has held many excellent webinars during 2013, with recordngs on the web
They are making a Diabetes and Vitamin D Webinar: August 27, 2013
Grassroots Health summary of diseases vs levels of vitamin D

See also VitaminDWiki
- Overview Diabetes and vitamin D which has the following chart - found a 7X decrease in Diabetes with > 2,000 IU of vitamin D
Type 2 diabetes 1.5X more likely if low vs high vitamin D – meta-analysis Feb 2013
Diabetes 3.5X less likely if more than 25 ng Vitamin D – Sept 2012
Diabetes 6X more likely for those abdominal obese who have insufficient vitamin D – June 2012
25 ng Vitamin D reduced chance of diabetes by 43 percent -review July 2011
4 percent less type 2 diabetes for every 4 ng more vitamin D – meta-analysis May 2013