Heath AK, et al. - A case-cohort study was conducted within the Melbourne Collaborative Cohort Study (MCCS) to examine the prospective relationship between vitamin D status and type 2 diabetes and the possible role of reverse causality. This investigation 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, the concentration of 25-hydroxyvitamin D (25(OH)D) was measured in samples collected at recruitment. It was observed in the findings that vitamin D status was inversely correlated with the risk of type 2 diabetes, and this relationship did not appear to be explained by reverse causality in this sample of middle-aged Australians.