A case-control study finds higher serum levels of selenium in patients with diagnosed diabetes mellitus than that in patients without the disease.

The study finds those with highest selenium were five times as likely as those with the lowest selenium to be diagnosed with diabetes mellitus.

Does this study mean that selenium causes diabetes mellitus?   It is not necessary.  It could be that the patients with diabetes mellitus took selenium supplements as a measure to help their disease. Taking selenium supplements surely raises the serum levels of selenium.

Chia-Wen Lu, Hao-Hsiang Chang, Kuen-Cheh Yang, Chia-Sheng Kuo, Long-Teng Lee, Kuo-Chin Huang  High serum selenium levels are associated with increased risk for diabetes mellitus independent of central obesity and insulin resistance, BMJ Open Diab Res Care 2016;4:e000253 doi:10.1136/bmjdrc-2016-000253

Other studies like the one conducted by researchers at Kashan University of Medical Sciences, Kashan, I. R. Iran indicates that at 200 μg/day, selenium supplementation in patients with type 2 diabetes mellitus and coronary heart disease significantly decreases insulin, HOMA-IR, HOMA-B, and serum hs-CRP among other benefits. (david liu)