Heath AK, et al. - A case-cohort study was conducted within the Melbourne Collaborative Cohort Study (MCCS) to examine the prospective connection between vitamin D status and type 2 diabetes and the possible role of reverse causality. The study involved a random sample of 628 participants who developed diabetes and a sex-stratified random sample of the cohort (n=1,884). Using liquid chromatography-tandem mass spectrometry in samples collected at recruitment, the concentration of 25-hydroxyvitamin D (25(OH)D) was measured. They found that vitamin D status was inversely correlated with the risk of type 2 diabetes in this sample of middle-aged Australians, and this relationship did not seem to be explained by reverse causality.